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First published 2005

Library of Congress Cataloging-in-Publication Data

Olver, Jane.

Ophthalmology at a glance / Jane Olver.

p. ; cm.

ISBN-13: 978-0-632-06473-1

ISBN-10: 0-632-06473-0

1. Ophthalmology —Outlines, syllabi, etc.

2. Ophthalmology —Examinations,

questions, etc. [DNLM:

1. Eye Diseases —Examination Questions.

2. Ophthalmology —methods —Examination Questions. WW 18.2 O52o 2005]

I. Cassidy, Lorraine. II. Title.

RE50.O45 2005

617.7 —dc22

2004011464

ISBN-13: 978-0-632-06473-1

ISBN-10: 0-632-06473-0

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Contents

Preface 6

25.

Common eyelid malpositions 56

Acknowledgements 7

26.

Lacrimal (tearing) 58

27.

Basic orbital assessment 60

Section 1: Principles of ophthalmology

28.

Orbital and thyroid eye disease 62

Introduction: what is ophthalmology? 8

Medical student aims 10

Section 9: Sub-specialty —External eye disease

Social and occupational aspects of vision 12

29.

Common conditions affecting the external eye 64

30.

Common conditions affecting the cornea 66

Section 2: Ophthalmic history and examination

31.

Therapeutic contact lenses 68

Taking the history and recording the findings 14

32.

Corneal and laser photorefractive surgery 70

Visual acuity in adults 16

Examination of visual fields 18

Section 10: Sub-specialty —Corneal, refractive and

Other visual functions 20

cataract surgery

33.

Cataract assessment 72

Section 3: Correction of refractive errors

34.

Cataract surgery 74

Basic optics and refraction 22

35.

Cataract surgery postoperative care 76

Glasses, contact lenses and low-vision aids 24

Section 11: Sub-specialty —Glaucoma

Section 4: Basic eye examination

36.

Glaucoma—the basics 78

10.

External eye and anterior segment 26

37.

Detecting glaucoma 80

11.

Posterior segment and retina 28

38.

Medical and surgical treatment of glaucoma 82

12.

Use of eye drops 30

Section 12: Sub-specialty —Vitreoretinal and medical retina

Section 5: Acute ophthalmology

39.

Retinal detachment 84

13.

The red eye 32

40.

Retinal and choroidal anatomy and imaging 86

14.

More on the red eye 35

15 Ophthalmic trauma principles and management of

chemical injuries

Medicolegal considerations

Meticulous history recording, clinical examination, visual

The principles of trauma apply:

Ophthalmic trauma is:

acuity recording, note taking and photographs of the

Airway

Chemical-Emergency

injuries are required. All trauma cases should be

Breathing

Blunt

regarded as potential medicolegal cases especially when

Cardiovascular

Sharp and perforating

an alleged assault has taken place or it has been an

Once these are stabilized the

occupational injury. Always sign your name clearly and

ophthalmologist is asked to examine

date and time the clinical notes accurately

the orbital / eye injury

Retinal tear and detachment

Vitreous haemorrhage

Subtarsal

Scleral rupture

foreign body

Choroidal rupture

Orbital haemorrhage

Traumatic optic

neuropathy

How to wash out a chemical injury

This is the only occasion when you wash out the

eye first then measure the visual acuity second.

It is an emergency!

Perforating

metal hook

IRRIGATE!!!

Water or saline

Corneal

foreign body

Penetrating

corneal injury

Lid laceration

Lens cataract

Iris dialysis

Orbital floor

Intraocular

fracture -

foreign body

fat ± muscle

Commotio

prolapse and

retinae

entrapment

Examination

Take a thorough history and record exactly what happened

Measure the visual acuity (in chemical injury can do after

washout)

Examine the eye systematically from the outside lids to

the retina, incuding pupil reactions

Dilate pupils for fundal examination

± Radiological investigation

Photograph for medicolegal purposes

36 Acute ophthalmology

Aims

WARNING

1 List the main causes of loss of vision due to trauma.

Sympathetic ophthalmia is a rare condition following perforating eye injury

2 How to wash out a chemical injury.

that results in chronic ocular inflammation and possibly loss of vision.

Principles of ophthalmic trauma

Basic ophthalmic trauma knowledge is required in the accident

The five main causes of loss of vision with trauma are:

and emergency setting, in intensive care and in the primary eye

1 Corneal scarring and anterior segment damage from severe alkali burn.

care clinic. The trauma patient may be managed by plastics and

2 Severe disrupted globe from penetrating injury, e.g. road traffic accident.

maxillofacial surgeons if there are facial or orbital fractures, or

3 Unrecognized intraocular metallic foreign body causing siderosis bulbi.

neurosurgeons if there is a head injury.

4 Compressive optic neuropathy from retrobulbar haemorrhage.

5 Traumatic optic neuropathy from optic canal bony or shearing injury.

Trauma can affect the periocular region, bony orbit, orbital contents, globe or optic nerve.

1 Eyelid and periocular and orbital haematoma —fully assess to rule out orbital floor fracture and fracture of base of skull

2 Orbital bony wall fracture —floor > medial wall with diplopia, needs repair

3 Eyelid subtarsal foreign body —evert lid and remove with cotton bud

4 Eyelids —partial or full thickness laceration: explore wound, exclude penetrating eye injury and repair within 48 h

5 Lacrimal drainage system —most commonly lower canaliculus; needs oculoplastics repair and stent, e.g. MiniMonaka tube

6 Conjunctival laceration —may need suturing; exclude more extensive deeper injury

7 Corneal abrasion —treat with topical antibiotics ± cycloplegia and a pad

8 Corneal foreign body —needs removal and dilated fundoscopy

9 Corneal penetrating injury ± sclera, iris, lens or retinal injury —all require urgent surgical repair

10 Hypahaema (blood in the anterior chamber) —can cause secondary glaucoma; needs urgent ophthalmic assessment

11 Dislocated lens —may need surgery to remove lens

12 Traumatic cataract —most need surgical removal

13 Glaucoma secondary to angle recession (i.e. damage to trabecular meshwork) —needs specialist treatment

14 Blunt vitreous haemorrhage and retinal commotio —needs vitreoretinal assessment to exclude retinal tear

15 Retinal tear/dialysis —needs urgent retinal surgery

16 Choroidal rupture —may lose vision if underlies macula; untreatable

17 Scleral perforation —needs surgical exploration and repair; if extensive may loose eye (enucleation)

18 Massive retrobulbar haemorrhage —needs urgent lateral canthotomy/cantholysis to decompress orbit

19 Traumatic optic neuropathy —needs to be treated with high dose steroids within hours

20 Traumatic cranial nerve injury —IVth, IIIrd and VIth cranial nerves need MRI scan

21 Complete globe disruption —needs enucleation within 14 days to prevent sympathetic ophthalmia

If any of the above are suspected refer immediately to eye casualty

Chemical injuries

check for fragments of cement, etc. and remove them. Swipe the

Which chemical? Substances include alkalis (lime, cement, plaster

cotton bud along the lower fornix to remove particulate debris.

or ammonia), acids, solvents, detergents, irritants (e.g. mace and

5 Now measure the visual acuity and check the eye, including

pepper) and super-glue. Alkalis (e.g. ammonia or wet cement) are

intra-ocular pressure.

the most destructive, penetrating the deep layers of the eye with

6 Admit.

time. In high concentrations they cause severe ischaemia of the

7 Topical treatment: intensive topical antibiotics, vitamin C and

conjunctiva, corneal limbus, cornea and sclera, and cause subse-

cycloplegia (to prevent pain) ± steroids. Treat raised intra-ocular

quent scarring and blindness. There may be associated severe

pressure as necessary.

uveitis and cataract formation. Wash out the eye immediately!

8 Oral high dose vitamin C.

1 Measure the pH of the tear meniscus if litmus paper is handy.

9 Later surgery if need —limbal cell transplant and penetrating

2 Otherwise, apply immediately topical anaesthetic drops if

keratoplasty (corneal graft).

handy.

3 Copious irrigation with normal saline or Ringer’s solution. If

neither are available, put the patient’s head under a cold water tap

KEY POINTS

or into a bowl of cold water —with eyes open! Irrigate/splash the

• All trauma cases are medicolegal cases until proved otherwise.

eyes for 5-10 min, then repeat the pH measurement.

• Ocular trauma is chemical, blunt or sharp (perforating).

4 Ensure that the surface of the eye and the upper and lower

• Alkali burns can cause blindness and must be irrigated immediately.

fornices are included. Using a cotton bud, evert the upper lid and

Ophthalmic trauma principles and management of chemical injuries 37

16 Specific features of blunt and sharp injuries

Blunt injuries

Small hyphaema

Blackball

Acute massive orbital haemorrhage with proptosis

Sphincter

3 mm

Subconjunctival haemorrhage

NB May need urgent lateral cantholysis and canthotomy

pupil

and chemosis

to drain a traumatic retrobulbar haemorrhage

ruptures

Retinal and choroidal blunt injury

Choroidal rupture

(yellow-white streak)

Commotio retinae

(white)

Commotio retinae is likely

to recover but the rarer choroidal rupture

can persist and, if on the macula, cause

severe decreased vision

Dislocated lens

WARNING

CT scan of left orbital medial wall and floor fracture -

Exclude small entry wound of an intraocular foreign body (IOFB). Dilate the pupil and

patient has severe enophthalmos and diplopia from

examine the fundus to exclude IOFB. If there is a history of hammering, use orbital X-ray to

restricted eye movement

exclude IOFB

Sharp injuries

Anterior segment sharp injury

Lens perforation

Corneal foreign bodies

Axial corneal

full thickness

laceration

Iris pulled up

to wound

Corneoscleral

laceration

Corneal perforation with

Medial eyelid and lacrimal canaliculus

fishing hook - may have

avulsion. Needs primary repair and

perforated lens

canalicular intubation

Subtarsal

Scratch marks on

foreign body

cornea lightly staining

Remove with a cotton bud or sharp

needle with good illumination and

magnification. May leave a rust ring

which needs later further removal

with a needle

Double eversion of upper eyelid

Severe ocular trauma with a

corneo-scleral rupture, lens

Exploratory microsurgery is indicated

disclocation, retinal detachment

Intraocular foreign body

to determine the extent of the globe

and vitreous haemorrhage

Needs vitrectomy and removal

rupture and to carry out a primary repair

38 Acute ophthalmology

Aims

eyelid, corneoscleral, iris, lens and retinal lacerations. Often,

1 How to manage a retrobulbar haemorrhage.

though, the entry wound is small and a high index of suspicion

2 How to remove a corneal foreign body.

should therefore exist for hammering and other high velocity in-

3 How to manage a corneal abrasion.

juries. Perforating injuries require urgent exploration and repair

by the on-duty ophthalmologist. The vitreo-retinal and oculoplas-

Blunt injuries

tics surgeons work closely together with these patients. Sometimes

From a fist/cricket/squash/tennis ball/champagne cork, etc.

the eye must be enucleated when the injury is very severe.

• Causes lid echymosis, orbital and subconjunctival haematoma,

hyphaema, ± lens iris injury, vitreous haemorrhage and commotio

TIPS

retinae.

• Do not put pressure on an eye that may be perforated or contents may

• Look for associated conjunctival and corneal foreign bodies,

extrude!

abrasions and lacerations and a red reflex.

• X-ray for suspected intraocular foreign body.

• Exclude traumatic emphysema from bony fracture —rare.

• Exclude a perforating ocular injury, traumatic retinal detach-

Superficial corneal injuries

ment or optic neuropathy (vision will be markedly reduced with

Corneal foreign bodies

(FBs) and subtarsal foreign bodies

an afferent pupil defect and normal optic disc).

(STFBs). History of a particle entering the eye, either dust or

• Exclude orbital floor fracture by examining eye movements and

metal flying in whilst walking past a building site, grinding

for infraorbital numbness. If a fracture is suspected arrange an

metal/hammering/doing DIY.

orbital CT scan.

The following are the main blunt injuries seen.

Symptoms

• Painful photophobic red watering eye —worse for corneal FBs

Traumatic hyphaema

than STFBs.

This is blood in the anterior chamber. It can be microscopic (seen

only on slit lamp), or it can form a level, the height of which is

Signs

measured in millimetres, or it can be a complete blackball. Causes

• Corneal FB sits embedded superficially on corneal epithelium.

pain and blurred vision.

• STFB lies embedded on the upper tarsal conjunctiva and

causes typical superior corneal superficial epithelial abrasions.

Traumatic iritis

White cells and flare in the anterior chamber (seen only on slit

Management

lamp), causing dull pain and photophobia.

• Use topical anaesthesia to examine. Instil fluorescein drops to

help see the FB and epithelial scratches from the STFB.

Orbital haematoma

• Try and flick the corneal FB off with a cotton bud. If it is too em-

• Eyelid echymosis. There are usually superficial lacerations caus-

bedded, the ophthalmologist can use a sharp needle end to remove

ing the bleeding. Insert a topical anaesthetic drop to help open the

it at the slit lamp.

eye gently and measure the visual acuity, examine the eye move-

• Evert the upper eyelid to see and remove the STFB with a cot-

ments, exclude a perforating eye injury and look at the fundus.

ton bud wiped across it. Immediate symptomatic relief.

• Retrobulbar haemorrhage. This is potentially sight-threatening.

• Instil topical antibiotics, cycloplegic drops and pad for 24 h, then

There is pain, decreased vision, proptosis and diffuse subconjunc-

a short course of topical antibiotics.

tival haemorrhage extending posteriorly. It can follow periocular

infiltrative anaesthesia or blunt trauma (with orbital wall fracture)

Corneal abrasion

and be associated with a ruptured globe and carotid-cavernous

History of scratch from a sharp plant, paper, child’s finger nail, etc.

sinus fistula. Emergency lateral canthotomy and cantholysis is

necessary to relieve high orbital pressure and to reduce the risk of

Symptoms

Severe pain and FB sensation, photophobia and watering.

compressive optic neuropathy.

Signs

Retinal bruising (commotio retinae)

Blurred vision can occur due to retinal bruising and loss of central

Red eye with fluorescein staining epithelial abrasion.

vision from a choroidal rupture across the macula.

Management

• Use topical anaesthesia to examine.

Traumatic optic neuropathy

This may respond to high dose steroids or optic canal decompression.

• Instil fluorescein to show abrasion clearly with blue light.

• Pad with a cycloplegic drop and topical antibiotic.

Orbital floor fracture

Sharp objects heal initially but later can cause symptoms of noc-

Blow-out fracture of the floor or medial wall into the sinus. Orbital

turnal and early morning FB sensation —called recurrent erosion

soft tissue entrapment may cause diplopia and limited eye move-

syndrome (RES).

ments. Enophthalmos may not be immediately apparent until

KEY POINTS

swelling/haemorrhage has settled.

• Retrobulbar haemorrhage — canthotomy + cantholysis saves vision.

• Evert the upper eyelid to remove a subtarsal foreign body with a cotton bud.

Sharp, penetrating and perforating injuries

• Corneal abrasion from a sharp object can cause RES.

Sharp objects, e.g. glass, spiky plant, hammer and chisal, cause

Specific features of blunt and sharp injuries 39

17 Sudden painful loss of vision in a non-inflamed eye

Sudden painful loss of vision

Sudden loss of vision associated with eye pain or headache in the

1 mm

white non-inflamed eye needs urgent attention as it may be due to

30 mm

sight or even life-threatening illness. The frequency of each disease

varies between age groups

Left altitudinal field defect

typical of anterior ischaemic

optic neuropathy

Giant cell arteritis (GCA)

1 mm

GCA - inflammation of the lining of large and medium sized

arteries. Immediate treatment with corticosteroids usually

relieves symptoms and prevents loss of vision

Optic neuritis/retrobulbar neuritis

Swollen disc of arteritic anterior

Elderly patient

ischaemic optic neuropathy - colour

Non pulsatile tender

and fluorescein angiogram appearance

temporal artery

May have swollen optic nerve or

± Headache (may be painless)

look normal if retrobulbar neuritis

± Jaw claudication

(i.e. inflammation behind globe)

± Weight loss

High ESR and CRP

Young woman

Pain on eye movement

Haemorrhage from pituitary tumour

May involve one

Benign intracranial hypertension (BIH)

optic nerve or

Pituitary

tract causing

tumour

sudden vision

Usually overweight females

loss

(though can occur in slim adults

and children of either sex)

Causes progressive field loss

Migraine

but also sudden visual loss

in the form of transient visual

Fortification spectra

obscurations (TVOs)

Scintillating

May see zigzag lines

scotoma

Can lose vision temporarily

Fields showing constriction.

Shaded area is where target is

Cast of blood supply of human eye

not visualized

Vortex vein

Optic nerve

Aetiology of optic neuritis

Central retinal

artery/vein

Typical: Idiopathic

Short posterior

Multiple sclerosis is the most common

ciliary artery

cause of retrobulbar neuritis

Atypical: Infectious (viral)

PONAA/circle of

Post infectious

Haller and Zinn

Granulomatous

Outer choroidal

Autoimmune

vessels

Contiguous inflammation of orbit,

Long posterior

sinuses or meninges

ciliary artery

40 Acute ophthalmology

Aim

—there is often associated eye pain, particularly induced by eye

1 Identify the main causes of sudden painful loss of vision in a

movement.

white eye.

• Typically, the vision improves over a period of 4-6 weeks,

2 Note that the pain may be ocular or cranial or both.

though this is not always the case.

• There may be other symptoms attributable to demyelination,such

Giant cell arteritis (GCA)/Temporal arteritis

as paraesthesia, bladder or bowel dysfuntion, and limb weakness.

This is visual disturbance with headache in elderly patients. This

• There may have been a recent viral illness.

inflammatory condition can result in occlusion of the larger blood

• The diagnosis of optic or retrobulbar neuritis can be aided by

vessels supplying the anterior optic nerve leading to anterior

performing visual evoked potential (VEP), which will demon-

ischaemic optic neuropathy (AION); this is referred to as arteritic

strate increased latency, i.e. a ‘delayed response’.

AION when the aetiology is GCA. There is also a non-arteritic

• MRI also helps to confirm the diagnosis, as the affected nerve

AION which is painless and is caused by occlusion or hypoperfu-

lights up, and it will show up demyelinating plaques in the brain.

sion within the smaller blood vessels supplying the optic nerve, the

• In most centres systemic steroid therapy for optic neuritis is re-

circle of Haller and Zinn (see figure of cast, opposite).

served for bilateral cases; as although it has been shown to speed

• In arteritic AION the patient is usually elderly and complains

up visual recovery, it has not been demonstrated to improve final

of:

visual outcome.

—sudden loss of vision, which may only affect the upper or

lower half of the visual field (altitudinal visual field defect);

Migraine

—headache (not always present).

This is visual disturbance with headache.

—sometimes a recent history of pain in the cheeks when

These visual disturbances most commonly present as fortification

chewing —jaw claudication;

spectra or scintillating scotoma, but occasionally as field loss or

—often a recent history of weight loss, myalgia and arthralgia.

even total loss of vision, which recovers. There is often a family

• On examination there may be temporal artery tenderness.

history of migraine.

• If there is associated chest pain suspect coronary artery involve-

ment, which may lead to cardiac infarction and death if not

Idiopathic intracranial hypertension (IIH) or benign

treated.

intracranial hypertension (BIH)

• Inflammation of the cerebral vessels can lead to a cerebrovas-

Presents with headache and transient visual obscurations (TVOs).

cular accident (CVA).

TVOs last for a few seconds, are unilateral or bilateral, and are

• Patients with GCA often have a high ESR, and invariably an

usually precipitated by movement or postural changes. They are

elevated CRP (though both may be normal initially).

pathognomonic of papilloedema.

• Definitive diagnosis is by temporal artery biopsy. This is best

• Occurs typically in obese females, but can affect slim individuals

done within a few days of commencing steroids.

of either sex, and children.

• Treatment, which must be swift in order to prevent blindness, is

• The optic discs are swollen and there is field loss.

with high dose steroids and requires hospital admission. Treat-

• An MRI should be performed to exclude a space-occupying

ment must not be delayed whilst waiting for a biopsy; once a clini-

lesion and an MRA to exclude venous sinus thrombosis, or an

cal diagnosis is made, instigate treatment immediately.

arteriovenous malformation affecting the venous sinuses.

• Patients with this condition may be on steroids for several years

• Thyroid dysfunction is a cause and must be excluded.

and must be put on calcium and a biphosphonate (to reduce

• Patients should be referred for urgent treatment, as this disease

osteoporosis), and a proton pump inhibitor. They must have

often results in permanent loss of the visual field.

their weight, blood pressure and blood glucose monitored.

• Treatment includes:

—conservative: weight loss; stop any medications that may

Optic neuritis/retrobulbar neuritis

cause BIH (e.g. NSAIDs, tetracyclines);

This is visual disturbance with eye pain.

—medical: acetazolamide;

• Inflammation of the optic nerve. If the entire anterior part of the

—surgical: lumbo- or ventriculo-peritoneal shunt, or optic nerve

nerve is inflammed, the optic disc will appear swollen (papillitis).

sheath fenestration.

• Retrobulbar neuritis (RBN): If the part of the nerve behind

the globe (i.e. the retrobulbar part of the nerve) is affected, with

Haemorrhage associated with pituitary tumour

sparing of the nerve head, the patient will have the same symp-

Rarely, a small haemorrhage into an undiagnosed pituitary

toms with reduced visual acuity, red desaturation and a relative af-

tumour can cause sudden loss of vision associated with headache.

ferent papillary defect, but the disc will appear normal in the acute

Such patients require urgent referral to a neurosurgical unit, as this

phase.

is a precursor of pituitary apoplexy.

Typical optic neuritis/retrobulbar neuritis:

• Most commonly affects young adults.

• Females affected more than males.

KEY POINTS

• Patient presents with:

• Painful loss of vision in a quiet eye may have a systemic cause, e.g. giant cell

—sudden loss of vision —this may vary from complete loss of

arteritis.

vision to alteration in colour perception (e.g. the patient may

• Retrobulbar neuritis —the disc looks normal in the acute phase.

complain of colours looking ‘washed out’ with the affected

• Idiopathic intracranial hypertension —the discs are swollen.

eye);

Sudden painful loss of vision in a non-inflammed eye 41

18 Sudden painless loss of vision

Retinal detachment

Symptoms

Vitreous haemorrhage

Sudden visual loss preceded by

floaters and flashes (photopsia)

Retinal tear

i.e. from

Pale detached

Subretinal fluid

neovascularization

retina

Retina detached

in diabetes

Vitreous

Retinal

Detached vitreous

haemorrhage

arteriole

Optic disc

in distance

Central retinal vein occlusion

Central retinal artery occlusion

NB Check

Intraocular pressure

Pulse ?Afibrillation

Viscosity

Carotids ?Bruit

Heart ?Murmur

Refer to cardiologist

Cherry red

Central or branch retinal

spot

vein occlusion - this is

Flame-shaped

a sub-total CRVO

haemorrhage

May see

or 3 quadrant BRVO

emboli

Tortuous

vessels

Vascular anatomy

Anterior optic nerve supply

Optic nerve layers:

Circle of Haller

Nerve fibre layer of retina

and Zinn or

Choroid (prelaminar)

PONAA

Sclera (lamina cribosa)

Paraoptic short

Retrolaminar optic nerve

posterior

ciliary artery

Vascular cast: Circle of Haller and Zinn

or perioptic nerve arteriolar

Pial arterioles

Central retinal artery (CRA)

anastomosis (PONAA)

Age-related macular degeneration

Cerebrovascular

accident

A sudden haemorrhage may

This affects

cause sudden loss of vision

visual pathways

Age-related macular degeneration—disciform scar

42 Acute ophthalmology

Aim

WARNING

Identify the main causes of painless loss of vision, in particular:

• All patients with vein occlusion must have their blood pressure checked,

• retinal detachment;

should be examined for arteriosclerosis, have their intraocular pressure

• vitreous haemorrhage;

checked and be checked for diabetes and systemic inflammation.

• types of vascular occlusion.

• Young patients presenting with CRVO or BRVO, or older patients in whom

there is no obvious cause, should be fully checked out for hyperviscosity

Retinal detachment (see Chapter 39)

syndromes.

• Sudden (sometimes gradual) painless loss of vision.

• Usually preceded by symptoms of flashing lights (photopsia)

Central retinal artery occlusion (CRAO) or a branch retinal

and/or floaters and/or visual field defects.

artery occlusion also presents as acute painless loss of vision.

• When the macula is not involved the visual loss involves the pe-

Aetiology:

ripheral field and visual acuity may be normal.

• Very high intraocular pressure, as seen in acute angle-closure

• Once the macula is involved the central vision is lost.

glaucoma.

• Arterial embolus from diseased carotid, valvular heart disease,

Management

atrial fibrillation.

Laser to retinal hole or retinal surgery ± vitrectomy.

• Arterial occlusion from atheroma or inflammation (e.g. giant

cell arteritis).

Vitreous haemorrhage

Haemorrhage into the vitreous cavity can result in sudden pain-

less loss of vision. The extent of visual loss will depend on the de-

WARNING

gree of haemorrhage.

All patients with CRAO need full cardiovascular work-up.

• A large haemorrhage will cause total visual loss

• A small haemorrhage will present as floaters and normal or only

Non-arteritic anterior (AION) or posterior ischaemic optic

slightly reduced visual acuity.

neuropathy (PION):

Aetiology:

• Results from occlusion or hypoperfusion of the small blood ves-

• Proliferative retinopathy —spontaneous rupture of abnormal

sels supplying the optic nerve head (AION) or posterior optic

fragile new vessels that grow on the retinal surface cause bleeding

nerve (PION).

into the vitreous cavity. Most common is proliferative diabetic

• In AION the optic disc is swollen; this swelling may be segmen-

retinopathy.

tal or involve the entire nerve head. There are usually associated

• Retinal detachment —a small retinal blood vessel may rupture

splinter haemorrhages at the disc.

when the retinal break occurs, bleeding into the vitreous cavity.

• In PION the optic disc looks normal.

• Trauma.

• There may be arteriosclerosis and arteriovenous nipping, de-

• Posterior vitreous detachment (see Chapter 39 for details) can

pending on the cause.

result in vitreous haemorrhage if, as the vitreous separates from

• Risk factors: arteriosclerosis, hypertension, hypotensive

the retina, it pulls and ruptures a small blood vessel.

episode, smoking, ‘disc at risk’ (e.g. small optic nerve head with no

• Age-related macula degeneration (AMD) —haemorrhage may

central cup).

occur into the vitreous from the abnormally weak vessels forming

a subretinal neovascular membrane (see Chapter 41).

Cerebrovascular accident (CVA)

A haemorrhagic or embolic CVA affecting the visual pathways

Management

will present as acute painless visual loss. Depending on the site of

Referral to an ophthalmologist to determine cause and manage

the lesion, the patient will have a corresponding field defect on

any complications (e.g. glaucoma due to red blood cells clogging

fields to confrontation. (See Chapter 50.)

up trabecular meshwork) that may occur.

Acephalgic migraine

Vascular occlusion (see Chapters 44 and 45)

This rare form of migraine presents with transient visual

Central retinal vein occlusion (CRVO) or a branch retinal vein oc-

disturbances involving one or both eyes in the absence of

clusion (BRVO) often presents with sudden painless loss of vision.

headaches.

Aetiology:

• Systemic hypertension.

KEY POINTS

• Raised intraocular pressure.

1 Retinal detachment is an ocular cause of sudden painless loss of vision.

• Hyperviscosity syndromes.

2 Central retinal vein occlusion is commonly caused by systemic

• Vessel wall disease

(e.g. diabetes, inflammation such as

hypertension.

sarcoidosis).

3 Central retinal artery occlusion may be caused by giant cell arteritis.

Sudden painless loss of vision 43

19 Gradual loss of vision

Be suspicious of the presence

When a patient presents with a gradual

of these common conditions

painless loss of vision, the cause will

Cataract

often vary with age, as certain

1 Uncorrected refractive error

conditions can be more common in

2 Cataract

certain age groups, e.g. cataract and

3 Chronic simple glaucoma

ageing maculoplathy in the elderly

4 Ageing maculopathy

Patient may complain of

glare initially or short-

sightedness

Refractive error

Correct with cataract

i.e. myopia in a teenager

surgery and intraocular

lens implant

Correct with spectacles

Age-related macular degeneration

Primary open angle glaucoma

Causes progressive visual field loss

Causes loss of

Treat with laser

Intraocular pressure (IOP) elevated

central vision

if amenable

+ 21 mmHg

Treat with ocular

antihypertensives

30 mmHg

Cupped disc

Age-related macular degeneration - geographic

macula atrophy

Tumours

Low tension glaucoma with cupped optic disc - need to

reduce IOP further (within normal range 10-20 mmHg)

Causes optic pathway compression

Diabetic retinopathy

Pituitary tumour

Optic nerve tumour,

e.g. glioma or meningioma

Occipital lobe tumour

Treat with laser

TIP

Elderly patients with cataract may also have ageing macular degeneration and the

contribution of each to their gradual painless loss of vision must be established

Diabetic maculopathy

prior to offering cataract surgery, or they may not get an optimum result

White circles are laser burns

44 Gradual loss of vision

Aim

toms, the optic disc will show evidence of damage and be very

Easily identify the common causes of gradual painless loss of vi-

cupped (end-stage disease).

sion in a white eye.

Glaucoma screening will often pick up POAG before any

severe damage has occurred and many patients are maintained on

Refractive error

topical medication without significant progression or the need for

Undetected and uncorrected refractive error is a common cause

drainage surgery (see Chapters 36-38).

of gradual visual loss in all age groups. Hypermetropia occurs in

young children, axial myopia in teenagers and young adults, and

Retinal disease

lenticular myopia in older patients.

Should be considered in the patient with none of the above causes

• Early cataract formation (nuclear sclerosis) may induce a re-

of reduced vision. It occurs particularly in patients at risk:

fractive error (most commonly myopia) in the elderly —they are

• Patients with diabetes (diabetic retinopathy).

briefly happy because they discard their glasses for reading! How-

• Patients with hypertension (hypertensive retinopathy).

ever, their distance visual acuity gradually deteriorates and they

• The elderly (age-related macular degeneration,ARMD).This is

require surgery.

the commonest cause of blindness in the elderly, in which their

• Children with refractive errors don’t complain until they attend

central vision for reading, colour and fine detail is affected. They

school and have difficulty seeing the blackboard (myopia) or

cannot see people’s faces or expressions clearly or read the labels

the print in their text books (hypermetropia or astigmatism),

on food in the supermarket or read the newspaper.

or complain of headaches at the end of the day due to eye

• Children or young adults with neurometabolic diseases or a

strain

(asthenopia). The child often doesn’t complain at all,

family history of retinal disease (e.g. retinitis pigmentosa).

and it is the teacher who notices a problem. Unfortunately,

• An individual with a history of an intraocular foreign body

for some children with hypermetropia, amblyopia has already

(IOFB) may develop siderosis bulbi; this is a condition where iron

occurred in one eye by the time the diagnosis is made and

from an IOFB that has not been removed can cause retinal toxi-

despite full refractive error correction with glasses and

city. The patient presents years after the initial injury with gradual

patching, vision in one eye does not improve. (See Chapters 9 and

loss of vision. The iris in the affected eye of a blue-eyed individual

21).

may have a greenish hue.

• Individuals taking medications known to cause drug-induced

Cataract

macular disease (e.g. chloroquine, hydroxychloroquine, tamox-

• A common cause of gradual loss of vision in the elderly. They

ifen, chlorpromazine, thioridazine, vigabatrin).

may notice nothing at all and the presence of an early cataract is

detected by their optician or they will have a gradual blurring of

Tumours and inflammation

distant, then near, vision. If the cataract is placed posterior in the

Any tumour that affects the visual pathway may cause symptoms

lens as a plaque (posterior sub-capsular lens opacity) they will

of gradual, painless loss of vision by pressure on the optic nerve or

notice glare and reduced vision in bright sunlight with improved

eye. Examples include:

vision indoors.

• Intraocular tumour (e.g. choroidal malignant melanoma or

• It may also occur in younger age groups who are at risk (e.g.

choroidal metastases from the breast or prostate in adults,

patient with diabetes, patients on steroids, patients with chronic

retinoblastoma in children)

uveitis and those with a family history of cataract).

• Intraocular lymphoma, which may masquerade as bilateral

• Cataract may also occur in young children (congenital cataract).

uveitis.

It is very important to check the red reflex of any child who pres-

• Tumour of the optic nerve (e.g. meningioma or glioma).

ents with reduced vision, and any baby who does not fix and follow,

• Tumour of the orbit or optic nerve (e.g. orbital lymphoma, sphe-

as they require urgent treatment with patching and glasses to pre-

noidal wing meningioma, dysthyroid eye disease).

vent amblyopia. (See Chapter 21).

• Any brain tumour involving the visual pathways (e.g. pituitary

tumour, occipital lobe tumour).

Primary open-angle glaucoma (POAG) (chronic simple)

These are not common and should always be considered when no

Causes slowly progressive painless visual field loss.

other cause can be found.

• It is most commonly seen in adults over 40 years of age, though

it can occur in younger adults.

• Risk factors include Afro-Caribbean origin, family history of

KEY POINTS

primary open angle glaucoma and hypertension.

• Myopia is common in young teenagers.

• The patient is usually completely unaware that they have open

• Patients with POAG are usually unaware of their disease.

angle glaucoma and it is detected by their optician finding raised

• Cataract and ageing maculopathy cause decreased vision in the elderly.

intraocular pressure or noticing a cupped disc.

• Tumours are a rare cause.

• By the time a patient with glaucoma presents with visual symp-

Gradual loss of vision 45

Aim

• VEP: the child has electrodes on its head which record brain

How to assess visual acuity in different aged children.

signals if they see the pattern on the screen.

Visual development

Infant (up to 2 years)

A child’s vision continues to develop after birth and maturation

Cardiff cards

does not fully occur until after age 2 years. Normal visual develop-

• A more accurate way of recording vision in these infants is to

ment in both eyes is important for the child to perceive the world,

use Cardiff cards (CC).

their education and social interactions.An infant who appears not

• Each card has a line drawing of a familiar object on either the

to see well may have delayed visual maturation or a more serious

upper or lower half of the card, and the thickness of the lines vary.

cause. Measuring visual acuity in children requires skill and pa-

According to the thickness of the line, the card will have a letter

tience, but even simple techniques can be used to elicit vision and

(e.g. CC H) and a Snellen equivalent (Sn Eq) on the back (e.g. 6/6

reassure the parent.

for the finest line).

• From a distance of 50 cm or 1 m, the cards are rapidly shown to

Newborn child up to 2 months

the child and the examiner observes the child making vertical eye

Assessment of vision in the neonate is dependant on the age and

movements up and down to the corresponding picture, and

behavioural state of the child. Because the child is pre-verbal you

records the acuity as, for example, ‘CC H at 50 cm-Sn Eq 6/9’. If

depend on their eye movements for information about visual

possible the acuity of each eye should be recorded separately.

function. If the child is smiling (usually at 6 weeks), then you smile

at the child without making any noise, and if they smile back, you

Toddler (2-3 years)

know they can see!

Once the child can speak you can ask them to identify verbally

There are a number of techniques used to test vision.

some simple and familiar pictures.

Fix and follow

Kay’s pictures

• Use a large brightly coloured shiny toy to see if the child fixes

• The most common method of assessing vision in this group is

and follows.

with Kay’s pictures.This test consists of a booklet of cards, on each

• With the child sitting on their mother’s knee, move the toy

of which there is a line drawing.

slowly from left to right about 50 cm in front of the child’s face. If

• Each line drawing has a Snellen equivalent depending on the

the child can see he will only follow the toy if he is awake and if the

size of the drawing (i.e. the largest drawing is equivalent to the 6/60

toy is moved extremely slowly as eye movements are immature at

letter on the Snellen chart).

this age.

• The examiner stands 6 m from the child and asks him to identify

• If possible, test each eye separately, by occluding one eye with

each picture.

an occlusive patch.

• If the child is too shy to tell you what each picture is he will usu-

• If the child fixes and follows the target, record the vision as ‘fixes

ally whisper it to his parent who in turn will indicate to you if he

and follows’.

was correct.

• If the child doesn’t follow the toy this may be because

he can’t see or is drowsy, or he is just not interested —try again

Young children (4-5 years)

later.

Sheridan-Gardner test

• The child is given a card with several letters randomly arranged

Spinning

on it.

Whilst spinning the child, observe his eye movements. He will have

• The examiner stands 6 m away and presents single letters on a

nystagmus during spinning if he can see. This is the vestibulo-

card of varying Snellen equivalence.

ocular reflex or VOR. When you stop, the nystagmus will change

• The child is asked to match each letter with the letter on his

direction for 1 or 2 beats in a seeing child. This is post-rotational

card. Each eye is examined separately and the acuity recorded.

nystagmus. If it persists the child is either severely visually im-

paired or has a cortical lesion.

KEY POINTS

• In newborn children use ‘fix and follow’ or spinning to elicit presence of

Other clinical tests

vision.

Preferential looking (PL) and visual evoked potentials (VEP).

• In infant less than 2 years old use Cardiff cards.

• PL: a card with different sized grating patterns on one side and

• In infants aged 2-3 years use Kay’s pictures.

plain on the other is shown to the infant who will look towards the

• In children aged 4-5 years use Sheridan-Gardner letters.

grating side if they can see it.

Visual acuity in children 47

21 Strabismus (squints)

Examination

Long-sight (hypermetropia) and convergent squint (esotropia)

Corneal Hirschberg reflection test - to detect a squint

Left accommodative esotropia

Fully corrected by wearing hypermetropic glasses

The corneal reflex position is observed - each mm of

displacement is equal to about 15 prism dioptres (7 degrees)

Example: Right 45 prism

dioptre convergent squint

(esotropia)

Assessment of ocular movements in 9 positions of gaze (primary gaze and

The cover tests

8 directions)

1. The cover-uncover test - to detect the presence of a squint:

Note the defective movement

Upgaze

Observe if one eye is preferred for fixation

of the left eye in left gaze

Ask the patient to look at the fixation target - if in a child

in left lateral

this can be a light or toy

rectus palsy

Dextroversion

Latroversion

Occlude (for a few seconds) the eye that appears to be fixing.

As you cover the eye, watch the other uncovered eye to see if it

Esotropia in

moves to take up fixation

primary gaze

Remove the occluder and see if the original eye retakes up

Limited left

fixation. If it does, it is the preferred fixating eye and the other

Downgaze

abduction

eye has a squint (non-alternating heterotropia)

Do this for near and then distance vision

Amblyopia therapy - Patching

Left good eye is patched

in order to encourage use

of right amblyopic eye

2. The alternate cover test - to detect a latent squint or

phoria in a patient with straight eyes on cover test:

Orthoptic definitions

Ask the patient to fixate on an object

Cover one eye then rapidly move cover to the other eye

i) Strabismus / squint

Repeat rapidly several times

Malalignment of the two eyes. If it is constantly present, it is manifest, but if it

Observe the movement of the covered eye as it becomes

is only detected on dissociation with an alternate cover-uncover test, it is latent

uncovered

ii) Binocular single vision (BSV)

If it moves inwards to take up fixation the patient has an

The use of both eyes together to achieve binocular depth perception - stereopsis

‘exophoria’

iii) Amblyopia - ‘lazy eye’ in 2% of the population

Do test for near and then distance

Amblyopia occurs from insufficient use of the eye(s) during visual development

Also can be used with a prism bar to measure the maximum

(birth - 7 years) commonly due to the presence of a manifest squint

size of a squint

and/or refractive error. The brain suppresses the image from a deviating or

defocused eye, particularly under 2 years of age - the sensitive period - when

Example cover test:

visual development is especially vulnerable to disruption. Other causes include

When the left fixing eye is covered with an opaque occluder,

congenital cataract or ptosis

the right eye moves inwards to take up fixation of the target.

iv) Amblyopia therapy

The squint is divergent (exotropia)

The treatment of squints in childhood with glasses and patching

v) Heterophoria = latent strabismus

Both eyes look straight but deviate on dissociation. It is common and usually

does not need treatment. Types: esophoria - convergent (inwards), exophoria -

divergent (outwards), hyperphoria - upward, hypophoria - downward

vi) Heterotropia = manifest strabismus in 5 - 8% of the population

One or other eye is not directed towards the fixation point. Types: esotropia -

convergent, exotropia - divergent, hypertropia - upward, hypotropia - downward

Squint

vii) Concomitant strabismus

The size of the squint is measured with a prism bar

The deviation remains the same in all directions of gaze

viii) Incomitant strabismus

The angle of deviation changes with the direction of gaze

ix) Patching

Prism alternate cover test

The patch completely covers the good eye to encourage the bad eye (amblyopic

one) to be used and develop vision. Generally unsuccessful after age 7 years

x) Diplopia

Double vision

Sub-specialty —Paediatric ophthalmology

Aims

Childhood concomitant and congenital incomitant squint

1 Understand squint terminology.

Orthoptist

2 Do a cover test to detect a squint.

• Measures visual acuity (VA).

3 Know the basic principles of amblyopia therapy.

• Detects and measures squint using cover tests.

• Assesses eye movements.

Children with a squint will not ‘grow out’ of it. There may be a sin-

• Assesses binocular vision (including tests for stereopsis).

ister cause such as cataract or retinoblastoma, so do a red reflex.

• Monitors amblyopia therapy with patching ± atropine occlusion.

Any child suspected of having a squint should be referred to an or-

thoptist and ophthalmologist for assessment.

Refraction

Orthoptists are allied health professionals who assess patients

The optometrist or ophthalmologist performs refraction

with diplopia, strabismus and eye movement defects. They work

(cycloplegic if child aged <7 years). In fully or partial accommoda-

closely with ophthalmologists in the management of children’s

tive esotropia with high hypermetropia, wearing glasses will fully

visual development, testing paediatric visual acuity (see Chapter

or partially correct the squint as well as improve visual acuity, and

20) and treating amblyopia.

surgery may not be required.

Aetiology and pathophysiology

Amblyopia therapy

Concomitant strabismus

Spectacles (if applicable) and a patch worn on the better eye for a

• Binocular single vision (BSV) usually develops by 3-5 months

specified number of hours per day, depending on the child’s age

old. If BSV does not ‘lock in’, esotropia (convergent squint) can

and VA.

develop at this time, although most concomitant squints develop

later at around 2-4 years, particularly with hypermetropia.

Surgery

• Any cause of reduced vision in one eye interrupts BSV and re-

Strabismus surgery is performed if the squint is socially unaccept-

sults in a squint, e.g. cataract, retinoblastoma or anisometropia.

able and to restore/improve binocular vision. In esotropia, the

• Children with a family history of strabismus or refractive error

horizontal rectus muscles are operated; recessing the medial

and those with developmental abnormalities have a higher inci-

rectus and resecting the lateral rectus or bimedial rectus recessions.

dence of concomitant squint.

Acquired incomitant squint (children and adults)

Incomitant strabismus

• The underlying cause must be established and treated (e.g.

• Congenital causes are rare, e.g. third, fourth or sixth nerve palsy.

intracranial tumour, diabetes, hypertension).

• Acquired incomitant squint presents with diplopia in adults.

• Orthoptic management is by joining diplopia with Fresnel

A child may adopt a compensatory head posture to minimize

prisms or prisms incorporated into the spectacle prescription.

diplopia and therefore may not complain of diplopia. A very

• Surgery is performed if BSV is not comfortably restored once

young child will suppress the second image and develop ambly-

the extraocular muscle(s) recover or have been stable for at least

opia if untreated.

6 months.

• Acquired causes include cranial nerve palsy (paralytic) second-

ary to intracranial pathology, thyroid eye disease and postorbital

floor fracture (restrictive).

KEY POINTS

• Esotropia is a convergent squint.

Management

• Amblyopia must be treated early —ideally before age 5 years.

Orthoptists, optometrists and ophthalmologists collaborate in the

• Beware: squint may be a presentation of an intracranial tumour or

management of squint using a combination of glasses, surgery and

retinoblastoma.

orthoptic treatment.

Strabismus (squints) 49

22 Neonates

Leukokoria

Retinopathy of prematurity

Dragged disc

Proliferating retinal vessels on ridge

There is an International classification of retinopathy of prematurity (ROP) where

worsening stages are recognized. The retina is divided into zones for its development

Temporal

equator

Leukokoria - a white coloured pupil

Zone III

- exclude congenital cataract or

Zone II

retinoblastoma

Zone I

3 9

Retinoblastoma

Hereditary (usually bilateral) or sporadic (usually

unilateral)

Ora

Treatment: Radioactive plaque or enucleation and

serrata

adjuvant chemotherapy

Survival: Untreated only 2-4 years (brain metastases).

Treated 90-95% 5 year survival

Screening for ROP

Congenital glaucoma with buphthalmos

• Infants <1500 g

• 31 weeks or less gestational age

• Begin at 6 weeks post-natally, not immediately

• Two-weekly intervals

• Weekly if ROP develops until it regresses or is treated

• Indirect ophthalmoscopy and indenter to see the

peripheral retina (pupils dilated)

CNLDO

Buphthalmos—child with big watering

Buphthalmos examination under anaesthesia—

photophobic eyes and corneal oedema

intra-ocular pressure monitoring with hand-held

tonometer

Microphthalmia

Right eyelid coloboma and microphthalmos.

Right microphthalmia with soft tissue

Congenital nasolacrimal

Partial cryptophthalmus (hidden eye)

expander. Left iris coloboma

duct obstruction

50 Sub-specialty —Paediatric ophthalmology

Aims

• Suspect Neisseria gonorrhoeae or Chlamydia trachomatis until

1 Differential diagnosis of leukokoria.

proved otherwise as both can cause blindness.

2 Main sight-threatening eye problems in neonates.

• Systemic and topical treatment is essential.

3 Management of a watering eye.

• Refer both parents to STD clinic.

In a neonate the three most important topics are leukokoria,

Buphthalmos (see Chapter 36)

retinoblastoma and ophthalmia neonatorum.

• A large eye in an infant associated with congenital glaucoma

and a cause of blindness/defective vision.

Leukokoria

• The infant has photosensitivity and watering with elevated in-

A white-coloured pupillary reflex seen when an ophthalmoscope

traocular pressure.

is shone at the pupil. Causes include:

• Needs specialized paediatric ophthalmology management.

• Congenital cataract.

• Hyperplastic primary persistant vitreous (HPPV).

Anophthalmos and microphthalmos

• Retinoblastoma.

• Rare total absence of an eye (anophthalmos) or a very small oc-

• Infections: toxoplasmosis and toxocariasis.

ular remnant (microphthalmos).

• Retinopathy of prematurity (ROP).

• The aim of management is to promote orbital bony develop-

• Coats’ disease.

ment by keeping the ocular remnant (microphthalmos or cyst)

and expanding the soft tissue of the orbit and eyelids sequentially,

Congenital cataract

prior to placing an ocular prosthesis (artificial eye).

• Presents as leukokoria, a dull red reflex, squint or nystagmus.

• If bilateral, the child may be visually inattentive.

Watering eyes/epiphora due to congenital nasolacrimal

• The eye may be smaller but there is usually no relative afferent

duct obstruction (NLDO)

papillary defect unless there is other retinal or optic nerve pathology.

• Causes watery sticky eyes.

• Causes include: idiopathic (most common), familial autosomal

• Aetiology: opening of the lower end of the nasolacrimal duct

dominant, galactosaemia and rubella (also causes microcephaly,

(where it enters the nose in the inferior meatus at the valve of Has-

congenital heart defects, corneal clouding and retinopathy).

ner) is often delayed for several months. Rare causes include ab-

• Needs urgent (within days) assessment with a view to cataract

sent canaliculus and absent or imperforate punctum.

surgery and subsequent amblyopia therapy. Some cataracts are

• Treatment of congenital NLDO:

small and need monitoring and amblyopia therapy.

—Advise the parent that the watering is likely to resolve by age

1 year in 90%.

Retinoblastoma

—Daily small finger massage over the lacrimal sac at the medial

• This malignant tumour of the retina is the most common in-

canthus to open the valve.

traocular tumour of childhood.

—Clean the eyelids with sterile saline.

• It often appears as a white mass growing into the vitreous and

—Antibiotic drops are only rarely required.

causing leukokoria when it is advanced/big.

—If there is an amniocoele (bluish lump) it will usually resolve

• Urgent assessment and treatment is required by a joint paediatric

with systemic antibiotic course. If this doesn’t work do an early

oncology and paediatric ophthalmology team in a specialist centre.

probing at <2 month’s age.

—An expressible mucocoele suggests nasolacrimal duct block

Non-accidental injury (NAI)

requiring dacryocystorhinostomy surgery.

A neonate with leukokoria or ocular trauma may have NAI.

—For persistant watering aged over 1 year, do a syringe and

probing (S&P) ± nasal endoscopic monitering.

Retinopathy of prematurity (ROP)

—If recurrent epiphora, repeat S&P with endoscopic moni-

• This important cause of childhood blindness occurs in pre-term

toring and consider intubation or dacryocystorhinostomy

babies and is screened for by ophthalmologists.

(DCR).

• Treatment with cryotherapy or laser has limited success in

threshold disease.

Ptosis (see Chapter 23)

• Prevention remains the key.

A neonate with an upper eyelid drooping across the visual

• Advanced/untreated ROP may have leukokoria.

axis should be referred urgently to an ophthalmologist with a

• Complications of treatment include cataract and myopia.

view to urgent frontalis suspension surgery and amblyopia

• In severe ROP with retinal detachment, vitreoretinal surgery is

therapy. Otherwise usually wait until age 4 years if visual develop-

often only palliative.

ment is not threatened.

Ophthalmia neonatorum

• Notifiable disease.

• The neonate usually has a unilateral or bilateral purulent con-

KEY POINTS

junctivitis within a few days of birth.

• Leukokoria —retinoblastoma and congenital cataract.

• The ophthalmologist must examine the child and take swabs/

• A watering eye from congenital NLDO usually resolves by 1 year.

scrapes for bacteria (including Gram and Giemsa stains), Chlamy-

• Beware: congenital glaucoma may present with large or watery eyes.

dia immunofluorescent antibody test and viral culture.

Neonates 51

23 Infants and older children

Differential diagnosis in orbital cellulitis

Infants and older children

The most common visual problems (apart

• Rare malignant orbital tumour

from myopia) have usually been detected

of childhood that can

by age 2-4 years. The problems of a child

metastasize. It may present

over 2 and under 12 years relate commonly

as orbital cellulitis

to the eyelids, lacrimal system and orbits.

• Average age of onset: 7 years

Teenagers have their own visual problems

• Grows fast and progresses

with the onset of myopia, presentation of

• If suspected, urgent referral

Leber's optic neuropathy (usually in mid

and biopsy required

to late teens), “hysterical” loss of vision,

headaches and convergence insufficiency.

Post-septal orbital cellulitis

Rhabdomyosarcoma

Reduced vision from albinism has usually

– pre-drainage

been detected by this age

Ptosis

Allergy

Vernal keratoconjunctivitis causing

Vernal giant papillae

Congenital left ptosis

bilateral acquired ptosis

Lumps on and around eyelid

• Benign congenital conjunctival and

subconjunctival yellow fatty lesion.

Lies very close to the lacrimal

ductules, therefore excision is not

advised as it risks a severe dry eye

from lacrimal ductile damage

Orbital, peri-orbital and

Dermolipoma

eyelid haemangioma

Dermoid cyst

• Smooth round non-tender relatively

• Benign congenital tumour often

immobile lump in the superolateral

associated with eyelid coloboma in

> superomedial orbit that gradually

Goldenhar's syndrome. Only very

grows in size. Risk of rupture if in a

limited excision is recommended

prominent position. CT scan is

required to assess extent and plan

surgery. Removal of an intact cyst is

necessary as its yellow cheesy

Limbal dermoid

contents are very irritant

Infections

• Endemic in schools

• Causes chronic follicular

• Typically from pubic lice -

conjunctivitis. Small dome-shaped

unilateral or bilateral causing

itchy lesions around the eyelids and

itchy eyes with crusty lashes

on the hands or arms

from the nits and blood-tinged

debris. Pilocarpine gel to

remove

Molluscum contagiosum

Headlice = pediculosis

52 Sub-specialty —Paediatric ophthalmology

Aims

aberrant eyelid movements with chewing and talking to detect

1 Identify common paediatric eyelid and orbital problems.

Marcus Gunn jaw-winking ptosis. Check under the eyelid.

2 Know why and when to operate on ptosis.

3 Management of orbital cellulitis.

Type of surgery

This depends largely on the level of the levator function. If the

The infant has different problems from the neonate. The most im-

levator function is very poor (<5 mm) the eyelid is internally sus-

portant condition is orbital cellulitis, which must be diagnosed and

pended to the frontalis muscle (frontalis suspension). If there is

treated promptly. Other common paediatric problems encoun-

good levator function, the levator muscle is shortened (anterior

tered include persistent mild drooping eyelid (ptosis), a sticky wa-

levator resection, ALR). When there is a risk of amblyopia in

tering eye and eyelid lumps.

neonate because the lid covers the pupil most of the time, then ur-

Squints are covered in Chapter 21.

gent frontalis suspension with a prolene suture is required.

The child may later need autogenous fascia lata frontalis sus-

Orbital cellulitis

pension (where fascial strips are taken from their upper leg).

Distinguish between pre-septal and post-septal orbital cellulitis.

If the eyelid is only slightly drooping and the child can easily ‘see

The child can be quite ill and febrile, and requires admission.

out from beneath it’ by adopting a small chin-up head position,

there is less risk of amblyopia and the child can wait until aged 4

Pre-septal

years before having ptosis surgery.

• Pre-septal involves only the eyelids but can spread posterior to

the orbital septum to become post-septal.

• One or both eyelids are swollen and tender.

Persistant sticky watering eyes

• White eye, which moves fully with no impairment of vision or

• Blocked nasolacrimal duct requires dacryocystorhinostomy (DCR).

proptosis.

• Vernal/atopic conjunctivitis. Photophobic with swollen eyelids and itchy,

• Treat with i.v. antibiotics.

stringy discharge that is worse in summer —can give an acquired ptosis. His-

tory of atopy. Large giant papillae on tarsal conjunctiva and possibly small lim-

Post-septal

bal lumps (limbal vernal). Treat with topical anti-inflammatory drops.

• Potentially severe life-threatening condition (cavernous sinus

• Blepharitis. Red rimmed sticky eyes with a tendency to recurrent blepharo-

thrombosis), unless treated.

conjunctivitis and watering. Treat with lid toilet and topical antibiotic ointment.

• Painful orbital/eyelid red swelling and proptosis; child is fever-

ish and unwell.

• Associated with an upper respiratory tract infection and un-

Lumps on and around the eye

diagnosed sinusitis.

There are many different lumps —identify capillary haeman-

• May not be able to open eye to see limited eye movements.

gioma, dermolipoma, limbal dermoid and dermoid cyst.

• Conjunctiva red and swollen.

• Vision may be affected: reduced visual acuity and red desatura-

Capillary haemangioma

tion with a relative afferent papillary defect due to optic nerve

Swelling appears at birth or shortly afterwards, then increases in

compression.

size for about 6 months. Most common in the superonasal orbit

• Do a CT scan to exclude sinus disease and subperiosteal ab-

and eyelid. Grows slowly, during which it can cause mechanical

scess, which need surgical draining and bacteriology.

ptosis and risk of amblyopia if the lid covers the visual axis or its

• Infection from: Haemophilus infuenzae, Streptococcus,

weight causes astigmatism. Treated with local infiltration of

Staphylococcus negative rods or Gram.

steroids to speed up resolution and reduce the bulk of the

• Urgent admission, blood cultures and treatment with i.v.

haemangioma. Spontaneously regresses usually after age 1 year.

antibiotics.

Stye (external hordeolum)

• Lash follicle infection —hot red lump that resolves rapily.

WARNING

Rhabdomyosarcoma and leukaemia are important differential diagnoses of

Chalazion

bacterial orbital cellulitis.

• Lump due to an inflamed blocked meibomian gland duct, which

will usually gradually resolve over a few weeks without treatment.

• Topical antibiotic ointment for 7-10 days.

Ptosis (drooping eyelid)

• Incise and curette under short general anaesthetic if not im-

• Congenital dystrophic.

proving with treatment (see Chapter 24).

• Acquired third cranial nerve palsy (rare).

• Inflammation, e.g. vernal keratoconjunctivitis.

KEY POINTS

Ptosis assessment

• Ptosis —risk of amblyopia when eyelid covers the visual axis.

Measure the visual acuity, strength of the levator muscle in mil-

• Ptosis —usually wait until age 4 years before surgery is done.

limetres (levator function), vertical palpebral aperture distance

• Drain subperiosteal abscess in orbital cellulitis.

and skin crease height. Observe Bell’s phenomenon. Look for

Infants and older children 53

24 Common eyelid lumps

Eyelid and periocular anatomy

Orbital

Septum orbitale

Eyelid posterior

margin

Conjunctival fornix

lamella

Superior tarsal

Meibomian

Skin crease

plate

Tarsal plate

glands

Lash line

Conjunctiva

Meibomian orifice

Lateral

Medial palpebral

Eyelid anterior

Grey line

canthal

ligament

lamella

Mucocutaneous

tendon

Lacrimal sac

junction

Skin

Septum

Inferior tarsal

Orbicularis

orbitale

plate

muscle

Cross-section lids

Front view tarsal plates

How to do an I & C

Layers of the skin

Local anaesthetic (topical plus infiltrative)

Tumours may arise from any component of the skin

Chalazion or

Place a small eyelid clamp and evert the eyelid

meibomian cyst

Use an 11 blade to incise vertically into the cyst on

Keratin layer

Melanocytes

Epidermis

arises in tarsal

the tarsal surface (in a direction away from the eye

Basal layer

plate meibomian

and avoiding the eyelid margin)

Basal cell carcinoma

arises from here

gland

Curette spoon to curette out the jelly

Dermis

Place a firm pad plus chloromycetin ointment for up

Basement

membrane

to 24 h

Sebaceous

Continue the ointment three times a day for 4 days

gland

Subcutaneous

Follicle

layer

I & C chalazion

Sweat gland

Artery Vein Nerve

How to evert an upper eyelid

Cysts of Moll - simple fluid

(chalazion)

retention cysts from sweat glands

(a)

(b)

(c)

(d)

Patient looks down

Basal cell carcinoma (BCC)

Squamous cell carcinoma

Pull on eyelashes and place a

cotton bud above the skin crease

Right lower eyelid nodular BCC Right medial canthal nodular BCC

Mohs' micrographic excision

periocular tumour

Evert!

54 Sub-specialty —Eyelid, lacrimal and orbit

Aims

tissue locally. It can invade the orbit if neglected or inadequately

1 Recognize a chalazion and understand its treatment.

treated. Early treatment is recommended —incisional biopsy to

2 Recognize a basal cell carcinoma.

make the diagnosis and excisional biopsy with a 2-4 mm margin of

3 Treatment of periocular basal cell carcinoma.

clear tissue, to completely remove the tumour.

Nodular BCC is the commonest form and its edges are easy to

Differential diagnosis of periocular tumours

define. There is a rarer morphoeic type with ill-defined edges and

Many different lumps are found on the eyelids, both benign and

extent, which is more difficult to manage and has a higher recur-

malignant.

rence rate. BCC does not metastasize. Surgical excision and re-

• Benign: chalazion, papilloma, retention cyst and sebaceous cyst.

construction is the mainstay of treatment of BCC although

• Malignant:

cryotherapy and radiotherapy are occasional options.

—basal cell carcinoma (BCC);

—squamous cell carcinoma (SCC);

Mohs’ micrographic surgery

—sebaceous gland carcinoma (SGC);

Mohs’ micrographic excision of BCC is a special technique to re-

—malignant melanoma;

move the tumour with frozen sections of the deep bed of the

—Merkel cell tumour;

tumour to ensure complete excision, done by dermatological

—other rare, e.g. sweat gland tumours.

surgeons especially trained in the technique. It provides good

clearance of tumour with maximum normal tissue preservation

Benign lumps

and low recurrence. An oculoplastics-trained ophthalmologist

Chalazion/meibomian cyst

then does the periocular reconstruction.

Inflamed painful lid swelling due to a blocked meibomian duct —

there are at least 27 ducts in each eyelid and each one has the po-

Squamous cell carcinoma

tential to block! Initial treatment in an adult is by hot compresses

SCC is rarer than BCC but more rapidly growing with a greater

and topical antibiotic ointment four times a day for 2 weeks. If the

potential for spread, especially perineural. It is a red lump with

lump persists, do an incision and curettage (I&C).

a variable appearance. It is much more common in immuno-

If an assumed chalazion recurs, particularly in an older person,

suppressed patients, for instance post renal or liver transplant pa-

do an incisional biopsy urgently for histopathological analysis as

tients on long-term immunosuppression drugs.

this may be a sebaceous gland carcinoma (meibomian gland

carcinoma). This is highly malignant.

Sebaceous gland carcinoma

SGC may masquerade as a recurrent chalazion or unilateral ble-

Solar keratoses (actinic keratoses)

pharitis in an elderly female patient.A large incisional biopsy is re-

These are dry scaly patches due to dysplastic intraepidermal pro-

quired for histopathologic analysis. This tumour can spread by

liferation of atypical keratinocytes and occur on the face in older,

lymphatics and the patient requires radical neck excision. There is

fair-skinned persons who have lived in sunny climates. There is a

a significant 5-year mortality.

low risk of malignant transformation into squamous cell carcino-

ma. Fortunately many solar keratoses regress spontaneously over

Malignant melanoma

1-2 years, but 15% recur. Treatment is with cryotherapy or 5-

Very rare but potentially very serious. Most pigmented lesions

fluorouracil.

around the eye are benign but the usual caveats apply —if there is

an increase in size or bleeds, urgent referral is needed.

Malignant lumps

Basal cell carcinoma (‘Rodent ulcer’)

KEY POINTS

This is the commonest periocular malignant tumour. It occurs

• A recurrent chalazion may be a malignant tumour —sebaceous gland

most commonly on the lower eyelid, then medial canthus, upper

carcinoma.

lid and lateral canthus. It is typically a nodular pearly lump with no

• Basal cell carcinoma is the commonest eyelid malignancy.

hair or lashes on it, but with telangiectatic blood vessels. The cen-

• Mohs’ micrographic surgery is the gold standard for excising periocular

tral zone may bleed and ulcerate. It can be morphoeic and have in-

basal cell carcinoma.

distinct margins. It grows slowly by direct extension and destroys

Common eyelid lumps 55

25 Common eyelid malpositions

Supracilia

Nerve supply to eyelids

Limbus

Upper eyelid

Upper lid

Upper punctum

Levator palpebrae superioris (cranial nerve III) and Müller's superior tarsal

skin fold

muscle (sympathetic) open the upper eyelid

Plica

Cilia

Orbicularis oculi (cranial nerve VII) closes the eyelid

Lateral

Medial canthus

Lower eyelid

canthus

Caruncle

The capsulopalpebral fascia (linked to the inferior rectus muscle - cranial

Lower lid margin

Lower punctum

nerve III) and Müller’s lower tarsal muscle (sympathetic) help the lower lid

Lower lid skin crease

Pretarsal orbicularis

move 2-4 mm downwards on downgaze and help open the lids

Preseptal orbicularis

Orbicularis oculi (cranial nerve VII) closes the eyelid

Whitnall's

Pre-aponeurosis fat

ligament

Entropion

Distichiasis

Levator aponeurosis

Müller's muscle

Levator muscle

Orbicularis muscle

Superior rectus

muscle

Tarsal plate

Intracanal fat

Pretarsal orbicularis

Preseptal orbicularis

Inferior rectus

muscle

Congenital lower lid entropion

Müller's inferior

Inferior oblique

- epiblepharon

tarsal muscle

muscle

Ectropion

Involutional lower lid entropion

ii) Botulinum toxin A temporary

i) Causing red sore eye

oricularis chemodenervation (surgery

Involutional ectropion

Cicatricial ectropion

is the definitive treatment)

Contact dermatitis from glaucoma

drops (reversible on stopping drops)

Facial palsy with anaesthtic cornea

Graves’ orbitopathy (thyroid eye disease)

(VIIth and Vth CN palsies) causing

- mild proptosis, right upper and bilateral

neurotrophic keratitis and scarring

lower lid retraction

Eyelid and brow measurements

Lateral tarsal strip

ULB

LidF

Facial palsy (lower motor neurone) and lagophthalmos

UMRD

LMRD

The lateral tarsal strip is tucked into the lateral orbit at the lateral

LSS

canthus and sutured to the periosteum at the lateral orbital rim.

This is a widely used useful technique

ULB

= Upper lid brow

= Palpebral aperture

Definitions

LidF

= Lid fold

Trichiasis

rubbing of abnormal inturned eyelashes

UMRD

= Upper margin reflex distance

against the eye causing discomfort

Used to shorten eyelid in entropion

LMRD

= Lower margin reflex distance

Distichiasis

= additional row of aberrant lashes arising

and ectropion surgery

LSS

= Lower scleral show

from the meibomian orifices

56 Sub-specialty —Eyelid, lacrimal and orbit

Aims

Aetiology

1 Examine an eyelid.

• Involutional —older persons.

2 Identify entropion (lid in) and ectropion (lid out).

• Cicatricial causes, e.g. post blepharoplasty, actinic, following

3 Identify ptosis (lid down) and eyelid retraction (lid up).

skin tumour excision, etc., and contact dermatitis.

• Mechanical —the weight of an eyelid tumour pulling the eyelid

Lid function

outwards.

• Ocular protection.

• Facial palsy (VIIth nerve palsy).

• Tear film distribution.

Symptoms

Examine an eyelid

Watering, irritation, grittiness and redness.

• Measure visual acuity!

• Look at the whole face, eyebrow height and symmetry

Treatment

• Measure the vertical palpebral aperture (PA) and margin reflex distances

• Involutional ectropion —shorten the eyelid horizontally and

(MRDs) and amount of scleral show (SS) above or below the limbus in mm

turn the medial part inwards using a lateral tarsal strip and exci-

• Measure the levator function (LF) in mm—upperlid excursion from full

sion of a diamond shape of medial tarsal conjunctiva or medial

downgaze to full upgaze

spindle (LTS + MS).

• Assess orbicularis strength and Bell’s phenomenon (do the eyes roll up-

• Cicatricial ectropion —skin graft or flap to lengthen the anterior

wards under lid on closure?)

lamella; horizontal shortening may also be required.

• Exclude aberrant movements

• Contact dermatitis —stop the causative eye drops or change to

• Lag on downgaze —eyelid hangs up a bit on downgaze

preservative-free drops. No surgery needed.

• Detect lagophthalmos —eye remains partially open on attempted closure

• For facial palsy, see below.

• Exclude distichiasis, trichiasis, entropion and ectropion

• Examine tarsal conjunctiva and conjunctival fornices to exclude scar or

Ptosis

tumour

Definition of eyelid ptosis: Abnormally low position of the upper

eyelid margin caused by poor function of the levator palpebrae

Entropion

superioris or Müller’s muscle.

Entropion: Eyelid turns in towards cornea and lashes touch the

Paediatric ptosis see Chapter 23.

surface of the eye.

Actiology:

• Involutional or aponeurotic (thinning or dehiscence of the an-

Aetiology

terior part of the levator, the aponeurosis). There is good levator

• Involutional —older persons.

function (LF). Occurs commonly in the elderly.

• Spastic (causes by severe squeezing of the eyelids in response to

• Myogenic. LF is very poor. Includes the congenital dystrophic

ocular discomfort).

(fatty) levator muscles in children and myopathies in adults, e.g.

• Cicatricial entropion secondary to conjunctival scarring, e.g.

chronic progressive external ophthalmoplegia.

staphylococcal lid margin disease (mild entropion) or ocular

• Neurogenic. The LF is usually poor, e.g. IIIrd nerve palsy.

cicatricial pemphigoid (severe entropion) or trachoma.

• Mechanical. Usually good LF. A tumour weighs the eyelid

down, e.g. neurofibromatosis.

Pathogenesis

• Traumatic ptosis may be aponeurotic, myogenic or neurogenic.

Thinning of the lamellae and disinsertion of the lower lid retrac-

tors. The pre-septal overrides the pretarsal orbicularis causing in-

Symptoms

turning of the lower lid.

• Cosmetically poor appearance.

• Functional —reduces the visual field.

Symptoms

Ocular irritation, discomfort, reflex watering (hypersecretion),

Management

redness and occasionally keratitis if left untreated. It is worse lying

Depends on the type of ptosis and LF. Normal or good LF is

down, e.g. reading in bed.

>10 mm. Moderate LF is 5-10 mm. Poor LF is <5 mm.

• Good and moderate LF: anterior levator resection —tuck / ad-

Treatment

vance the levator aponeurosis or muscle.

1 Temporary treatment:

• Poor LF: frontalis suspension with autogenous fascia lata.

• Lid taping and topical lubricants.

• Botulinum toxin A injected into the pre-septal orbicularis alle-

Eyelid retraction

viates symptoms for up to 4 months but has to be repeated.

Lower motor neurone facial palsy (7th CN palsy) and thyroid eye

2 Surgery is the mainstay of treatment.

disease can both cause exposure keratitis. See Chapters 28 and 49.

• Lateral tarsal strip with everting sutures (LTS + ES).This short-

ens the lower eyelid horizontally and everts the eyelid.

KEY POINTS

• Simple everting sutures (ES) alone.

• Measurement is important in eyelids.

• Involutional entropion is treated temporarily with botulinum toxin A.

Ectropion

• Facial palsy causes lagophthalmos and a risk of exposure keratltis.

Ectropion: Lower eyelid turns outwards away from the eye.

Common eyelid malpositions 57

26 Lacrimal (tearing)

Lacrimal anatomy

Lacrimal syringing

The lacrimal drainage system consists of the punta,

canaliculi, lacrimal sac and nasolacrimal duct (NLD)

Lacrimal

Canaliculi

gland

Lacrimal

Lacrimal physiology

Tear

sac

The tears are produced by the lacrimal gland and the

accessory lacrimal tissue (glands of Krause and

meniscus

Lacrimal pump

Middle

Wolfring) and are swept over the eye surface with

turbinate

Nasolacrimal

each blink. Tear evaporation occurs (approximately

Inside of

duct (NLD)

25%). The marginal tear strip drains via the lower

nose

Inferior meatus

canaliculus predominantly (70%) and 30% via the

Inferior

upper canaliculus. The lacrimal pump mechanism

turbinate

refers to the action of the eyelids contracting and

pumping the tears into the lacrimal sac

Nasal endoscopy

This is a very useful technique that provides direct

observation of the nasal space both in out-patients

and during lacrimal surgery. A rigid Hopkins 4 mm 0∞

rigid nasal endoscope is used to look at the opening

Right mucocoele-chronic dacryocystitis

of the NLD into the nose and at the DCR surgery

site

Normal dacryocystography (DCG) - left side

DCG shows right anatomically blocked

shows free drainage contrast media into nose

NLD. Note that no contrast material

Left external skin approach

is seen entering the NLD

dacryocystorhinostomy (DCR) -

per-operative view

Lacrimal sac

Canula in inferior

canaliculus

Lacrimal sac

NLD

Canula in inferior

canaliculus

Dotted line shows

Contrast in lateral

where NLD should

wall of nose

normally fill

A mucosal-lined opening is made from

the lacrimal sac to the nose after the

Nuclear lacrimal scintigraphy - showing

intervening bone has been removed

left functional NLD block

Pooling of tears containing technetium 99

New opening

in the conjunctival fornix

from sac into

Blocked

nose for tears

Functioning DCR rhinostomy

NLD

Fluorescein passing freely down

lateral wall of nose

NLD

Lacrimal sacs

Canaliculi

Conjunctival fornix

Lacrimal

sac

Keratome

Middle

Endonasal endoscopic

turbinate

surgical DCR

Endoscope

- the lacrimal sac is

Inferior

Jones Pyrex bypass tube

approached from inside the

Floor

turbinate

- per-operative insertion

nose instead of via the skin

of nose

58 Sub-specialty —Eyelid, lacrimal and orbit

Aims

•

Slit lamp examination:

1 Understand the difference between hypersecretion and

—exclude blepharitis;

epiphora.

—exclude punctual stenosis;

2 Use of syringing in assessment of epiphora.

—tear meniscus.

3 Dacryocystorhinostomy.

•

Probe and syringe/irrigate lacrimal system

(use topical

Nasolacrimal duct obstruction is a common cause of epiphora

anaesthesia) After the punctum has been dilated, a curved

(watering eye). Surgery to correct this is called dacryocystorhinos-

lacrimal canula is gently introduced into the canaliculus and

tomy (DCR) and can be done via the nose (endonasal) or via the

advanced into the lacrimal sac and saline is irrigated. If there is

skin (external). However, there are many causes of a watering eye

passage of saline into the throat this indicates a patent system,

and careful assessment is required.

whereas no passage indicates a blocked system. Sometimes only

some saline goes down, indicating a partial NLD block.

Definitions

•

Special clinical tests: Jones’ tests used to confirm and localize

Epiphora: Reduced tear outflow from lacrimal system obstruction

functional epiphora (not used much).

at any point from the punctum, canaliculus, sac and nasolacrimal

•

Nasal endoscopy:

duct. Nasolacrimal duct obstruction is the commonest.

—The nasal endoscope is used to look inside the nasal space

Hypersecretion: Excess production of tears in response to stimu-

preoperatively to exclude nasal pathology such as tumours, in-

lation of the trigeminal nerve from corneal irritation (e.g. corneal

flammation and polyps as well as anatomical variations.

foreign body), dry eye or conjunctival irritation (e.g. blepharitis,

—It is also used to inspect the internal opening (rhinostomy)

conjunctivitis).

made by the DCR surgery and to check its function.

Functional epiphora: Epiphora in the presence of patent syringing

—A successful DCR has a positive functional endoscopic dye

without hypersecretion due to:

test (FEDT), i.e. a drop of fluorescein 2% placed in the conjunc-

• eyelid malposition, e.g. lower lid ectropion;

tival fornix is seen emerging from the rhinostomy a few seconds

• lacrimal pump failure, e.g. facial palsy;

later.

• punctual, canalicular and nasolacrimal duct stenosis (without a

•

Radiology imaging studies

complete obstruction).

—Dacryocystography (DCG) with radio-opaque material for

Mucocoele: A dilated lacrimal sac containing mucous. often seen

anatomical detail. Used to determine the site of the obstruction.

as a lump at the medial canthus. The nasolacrimal duct distal to it

—Lacrimal scintigraphy is a nuclear scanning technique using a

is blocked.

drop of technetium 99 placed in the conjunctival fornix and a

gamma camera to observe its passive drainage. It is used to de-

Pathogenesis

tect physiological tear drainage in the assessment of functional

• The commonest cause of epiphora is a blocked nasolacrimal

NLD obstruction.

duct (NLD). This can be primary from chronic inflammation with

subsequent fibrosis and stenosis, or less commonly, secondary

Surgery

from sarcoidosis, Wegner’s, tumour or trauma. DCR is the treat-

DCR can be external (via the skin) or endonasal (via the nose).

ment of choice.

• Aim of DCR. To relieve watering and/or sticky eye from NLD

stenosis/obstruction by creating a functioning rhinostomy be-

tween the lacrimal sac and the nasal space.

• External (skin incision) approach DCR has the best track

WARNING

record and is the gold standard —success rates 95-98%.

Canalicular disease. If there is severe canalicular obstruction (e.g. following

• Endonasal DCR (via the nose) approach DCR is less invasive

radiotherapy, some chemotherapy drugs, herpes simplex infection) a DCR is

but also has lower results, 70-86%. The rigid nasal endoscope

done with a Jones Pyrex glass tube inserted.

provides good illumination and magnification transnasally, with

either: (i) laser, (ii) surgical, or (iii) powered instruments to make

the rhinostomy. The xomed diamond burr has the best results.

Investigate the watering eye

Many patients prefer endonasal DCR because it avoids skin in-

History

cision. However, the advantage of external DCR is that its surgical

Stickiness/watering worse is outside or constant. There is an

outcome is still better than endonasal techniques.

inflamed or quiet lump at the medial canthus. History of nasal

disease, sinusitis, polyps or nasal trauma. Previous conjunctivitis,

eye drops and drugs.

KEY POINTS

• Ectropion is a cause of epiphora.

Assessment of the watering eye

• Endoscopic endonasal DCR avoids a skin incision.

• External examination of the forehead, periocular and medial

• External approach DCR still has the best results —95-98% success.

canthus to exclude eyelid malposition and mucocoele.

• Fluorescein dye retention test: watch a drop of fluorescein 2%

rapidly disappear from the conjunctiva if the system is patent or

dye retention if blocked.

Lacrimal (tearing) 59

27 Basic orbital assessment

Levator palpebral

Eye and orbit

superioris

Superior rectus

Lacrimal

Superior oblique

gland

Ethmoid sinus

Lateral

Medial rectus

rectus

Lacrimal sac

Zygoma

Inferior rectus

bone

Inferior oblique

Fat

Infraorbital nerve

Nasolacrimal

duct (NLD)

Maxillary sinus

Nose

Maxilla bone

Orbital bones

Medial orbital wall

Superior orbital

fissure

Sac/NLD

Ethmoid lamina

Eye

papyracea

Ethmoid

air cells

Optic foramen

Lacrimal bone

Medial

Zygoma

rectus

Inferior orbital

Lateral

fissure

rectus

Maxilla bone

Optic nerve

Zygomatico

Infraorbital

Optic

facial foramen

foramen

Zygoma bone

Proptosis / enophthalmos

Orbital cellulitis

Hertel exophthalmometry to measure proptosis / enophthalmos

Left orbital

subperiosteal

abscess and

sinus disease

Blue triangle lined up with marker line

before drainage

This patient measures 21 mm at

100 mm

Aims

Pseudophthalmia: Socket contains an orbital implant.

Assessment of a patient with proptosis. This chapter covers the

Microphthalmia: Socket contains a very small eye/ocular remnant.

anatomy of the orbit and the systematic approach to examining

Phthisical eye: A blind shrunken eye.

a patient with proptosis. The most common cause of proptosis

Enucleation: Removal of an eye in its entirety —detaching it from

in adult patients is thyroid eye disease, also known as Graves’

the optic nerve and the extraocular muscles.

orbitopathy.

Evisceration: Removal of the contents of the eye leaving

the outer sclera, attached optic nerve and extraocular muscles.

Definitions

Post-enucleation socket syndrome: Deep sunken ‘eye’ when the

Proptosis: Eye protruding.

volume of the removed eye has not been adequately replaced.

Enophthalmos: Eye sunken in.

Decompression orbit: Removing usually the medial and lateral

Anophthalmia: Socket contains no eye.

orbital walls to expand the orbit in thyroid eye disease.

60 Sub-specialty —Eyelid, lacrimal and orbit

Orbital anatomy

Enophthalmos. Is there a history of trauma and possible orbital

The bony orbit has four margins and walls and is adjacent to the

floor fracture? Is there a phthisical eye? Is there an ocular pros-

ethmoid sinus (medial) and maxillary sinus (inferior). It contains

thesis? Has the patient had an eye enucleated? Was there an or-

the optic foramen for the optic nerve and ophthalmic artery, the

bital implant placed after enucleation/evisceration? Is there a

superior orbital fissure (cranial nerves and blood vessels) and in-

secondary post-enucleation socket syndrome? Are the eye move-

ferior orbital fissure. The infraorbital nerve lies in the floor, partly

ments restricted? Is the socket lining contracted?

in a bony canal.The orbit contains a lot of fat and connective tissue

septae that support and cushion the eye and its muscles, optic

Check cranial nerve (CN) function

nerve, nerves and blood vessels.

• IIIrd, IVth and VIth CN: extraocular muscle movement.

• VIIth CN: upper facial musculature.

Orbital assessment

• Vth CN: corneal, periorbital and forehead sensation.

History

• Gradual or sudden onset. If slow/non-inflamed it is more likely

Feel the orbit

to be benign.

Palpate the orbital rim. If a mass is detected, is it separate from the

• Unilateral or bilateral.

rim? Describe its feel and shape and draw a picture of its shape

• Orbital swelling/sunken.

and location.

• Orbital pain.

• Periorbital redness (e.g. orbital cellulitis).

Complete the examination

• Periorbital numbness.

Palpate the temporal fossa for extension of swelling. Exclude

• Visual disturbance.

pre-auricular, submandibular and cervical lymphadenopathy.

• Double vision.

Examine the neck for thyroid enlargement or thyroid scar. Check

• Drooping eyelid.

sensation in skin around orbit.

• Systemic: malignancy or thyroid problem.

• Previous trauma.

• Ascultation for a bruit —caroticocavernous fistula.

WARNING

Orbital tumour spread. The orbit does not have lymphatics, but extensive tu-

Clinical examination

mour that involves the lids and periorbital area can metastasize to local lymph

Visual function (if eye present) and eye examination

nodes.

• Visual acuity and pupil reactions.

• Colour vision ± visual fields.

• Retina and optic disc.

Investigations

• CT scanning. Axial and coronal views show the position of the

Globe position

optic nerve well and also the sinuses and orbital walls (request

Measure proptosis with Hertel exophthalmometry —is it axial or

bone window settings too). Suspected vascular lesions need

non-axial?

contrast.

• MRI. Good for soft tissue but does not show bone so well.

• Orbital ultrasound. Colour Doppler ultrasound to measure size

Proptosis

and show bloodflow/velocity within lesion.

• Axial

(anteroposterior protruding globe) without horizontal or vertical

displacement. This suggests a generalized orbitopathy such as thyroid eye

disease or an intraconal mass.

• Non-axial. Horizontal or vertical displacement of globe caused by a

KEY POINTS

mass pushing it sideways. For instance, a lacrimal gland tumour in the

• Proptosis is axial or non-axial.

superolateral quadrant pushes the globe inferomedially.

• Palpate the orbit to help detect a mass.

Basic orbital assessment 61

28 Orbital and thyroid eye disease

Graves’ orbitopathy (thyroid eye disease)

Bilateral proptosis, periorbital swelling and left esotropia

Marked proptosis and redness - active phase

- quiet phase

CT scan - enlarged medial

and inferior rectus muscles

in Graves’ orbitopathy

Tumour behind eye

CT scan showing tumour

(benign)

Right proptosis from

large cavernous

haemangioma

Enucleation

Indications for enucleation include a painful blind eye, choroidal malignant melanoma

and a severely disrupted eye following trauma.

The eye is eviscerated if there is an intractable endophthalmitis

Post-enucleation socket syndrome - no orbital implant

placed at time of enucleation

Wearing a thick artificial eye

Thick artificial eye

Porous polyethylene sphere implant inserted into socket.

but still very enophthalmic

Orbital sphere implant is needed to replace lost volume

Aims

Graves’ orbitopathy

1 Management of Graves’ orbitopathy.

Most patients present within the first 6-12 months of hyperthy-

2 Recognize an artificial eye.

roidism. Male patients and smokers have a more aggressive dis-

This chapter cover proptosis, orbital masses and enucleation.

ease. There is an active phase with inflammation which lasts up to

1 year, and a subsequent inactive stable phase.The former is treat-

Common orbital problems

ed medically with immunosuppression (e.g. steroids and azathio-

• Adult:

prine) and once the disease is inactive surgery to the orbit, muscles

—Graves’ orbitopathy (thyroid eye disease) (most common);

and eyelids can be considered.

—idiopathic orbital inflammation;

—cavernous haemangioma;

WARNING

—lacrimal gland tumour;

Early orbital decompression surgery is only done if there is marked compres-

—secondary tumours;

sive optic neuropathy.

—nerve cell or sheath tumours.

• Child:

There is a varied presentation:

—dermoid cyst;

• Proptosis.

—haemangioma;

• Reduced colour vision from optic nerve compression.

—rhabdomyosarcoma;

• Restrictive strabismus with mainly inferior and/or medial rectus

—Craniofacial abnormality.

muscle enlargement causing diplopia.

62 Sub-specialty —Eyelid, lacrimal and orbit

• Eyelid retraction.

Orbital and lacrimal gland tumours

• Lagophthalmos.

Orbital and lacrimal gland tumours cause proptosis and require

• Exposure keratitis.

incisional or excisional biopsy by a trained oculoplastics orbital

• Conjunctival redness and cheimosis.

surgeon. Lymphoma and metastases are the commonest malig-

• Periorbital swelling.

nant tumours.

The aim of treatment is to preserve vision, with eyes comfort-

Many anterior and mid orbital tumours can be biopsied via a

able and looking normal, with full lid closure.

skin approach. More posterior intraconal and lacrimal gland

tumours (pleomorphic adenoma) require excision via a lateral

Graves’ orbitopathy management

orbitotomy.

Indication

Phase

Medical treatment

Surgery

Enucleation

Compressive Active

• Pulsed steroid

Orbital

When an eye is removed its volume must be replaced by a buried

optic

therapy

decompression

spherical orbital implant to which the rectus muscles are attached.

neuropathy

• Systemic

An ocular prosthesis (artificial eye) is made to match the normal

steroids,

eye; usually it is acrylic and hand painted. If the volume of the enu-

azathioprine

cleated eye is not replaced the patient has a sunken socket ap-

and orbital

pearance called post-enucleation socket syndrome and may need

radiotherapy

a secondary buried orbital implant.

Proptosis

Inactive

Orbital

decompression

Strabismus

Inactive

Adjustable suture

KEY POINTS

rectus recession

• Graves’ orbitopathy —do decompression before eyelid surgery.

• Important to replace eye volume lost at enucleation/evisceration with an or-

Eyelid

Inactive

• Graduated

bital implant and artificial eye.

retraction

retractor recession

(upper eyelids)

• Hard palate

mucosal graft,

alloderm or

auricular cartilage

(lower eyelids)

Periorbital

Inactive

Blepharoplasty

swelling

Skin changes Inactive

Laser resurfacing skin

Orbital and thyroid eye disease 63

29 Common conditions affecting the external eye

External eye and lid margin zone

Tear film

Lipid layer

Aqueous layer

Posterior margin

Meibomian orifice

Posterior margin

Meibomian orifice

Grey line

Mucin

Grey line

Lash line

Mucocutaneous

Corneal epithelial

Lash line

junction

cells (microvilli)

Tarsal

plate

Rhinophyma with lower eyelid ectropion, blepharitis and meibomianitis

Upper eyelid entropion - mild cicatricial from chronic

staphylococcal lid margin disease

Pit

Thick meibomian

secretion

Crusts

Red rimmed

margin

Collarettes

Upper eyelid cicatricial entropion

Upper eyelid held up

Everted upper eyelid

Conjunctival

Linear

scarring and

scarring

Punctate fluorescein

symblepharon

Tarsal

or rose bengal stain

(adhesion)

conjunctiva

Superior limbic keratitis

Ocular cicatricial pemphigoid

Conjunctiva

Scarring

Cornea

Posterior

marginization of

meibomian orifice

Lashes

and blunting of

touch

posterior margin

Pterygium

Ocular cicatricial pemphigoid

cornea

Aims

Diseases primarily affecting the tear

Detection and medical management of:

film/epithelium/conjunctiva

• blepharitis

• Idiopathic dry eye.

• dry eyes

• Severe dry eye associated with Sjögren’s syndrome and other

• allergic eye disease.

autoimmune conditions.

• Graft versus host disease.

Diseases of the external eye

• Stevens-Johnson syndrome.

• Blepharitis.

• Ocular cicatricial pemphigoid.

• Trachoma causing cicatricial entropion.

• Pterygium.

Treatment

• Allergic eye disease.

Treatment depends on the underlying cause in conjunction with

topical lubricating drops. If severe, corneal scarring with super-

ficial vascularization leads to reduced vision and even corneal

perforation.

64 Sub-specialty —External eye disease

Common conditions

idiopathic (approximately 50%) and secondary causes include

Blepharitis and meibomionitis

rheumatoid athritis, lupus or scleroderma.

Blepharitis

Other causes of dry eye

Low-grade chronic staphylococcal lid margin disease with ‘red-

• Stevens-Johnson syndrome.

rimmed’ eyelids in young adults and middle-aged persons.

• Ocular cicatricial pemphigoid.

Symptoms

• Lacrimal gland trauma (surgical excision or ductile destruction)

Itchy, sore, watery eyes.

and chemical, radiotherapy and thermal injury.

• Fibromyalgia.

Signs

• Chronic fatigue syndrome.

Red-rimmed lid margins, eyelash crusts and collarettes, and

distorted lid margin microanatomy: irregularities, pits and

Allergic eye disease

telangiectasia.

• Hayfever: seasonal allergic conjunctivitis. Bilateral, itchy, wa-

tery eyes with lid swelling and sometimes mucous discharge. It is

Management

a type 1 immediate immune response with histamine release to

• Daily lid hygiene using sodium bicarbonate or dilute baby

allergens such as pollen. It is worse in the young with a history

shampoo and cotton bud lash scrubbing.

of atopy. May also have rhinorrhoea and sneezing. Management

• Chloramphenicol ointment, or G fusithalmic

is with topical mast cell stabilizer (e.g. sodium chromoglycate or

• ±Doxycycline or Minocycline.

lodoxamide).

Meibomianitis

• Perennial allergic conjunctivitis. Bilateral, episodic symptoms.

Thick oily meibomian secretion causing stingy sore eyes and red

Triggered by allergens such as house-dust mites, moulds, pollens,

thickened eyelids. Often associated with rosacea. Management is

food preservatives and animal danders. Management is as for

as for blepharitis, adding tetracycline antibiotic for rosacea.

hayfever, plus oral and topical antihistamine when severe.

• Vernal keratoconjunctivitis sicca (VKC). This is a young per-

Upper eyelid entropion

son’s disease (7-11 years) with characteristic upper tarsal con-

Mild upper eyelid entropion from chronic staphylococcal lid mar-

junctival cobblestones (see Chapter 23). Also includes bilateral,

gin disease.

seasonal, red, puffy, itchy eyes with photophobia, watering and

mucous. It may induce ptosis. There are often perilimbal giant

Symptoms

papillae, known as limbal vernal. Management is as for hayfever,

Foreign body lash sensation and dry, gritty eyes.

plus topical steroids when severe.

Signs

• Acute allergic conjunctivitis. Sudden, unilateral, itchy lid

Trichiasis and punctate epithelial corneal stain.

swelling and marked conjunctival chemosis. Signs are worse than

symptoms. Triggered by plant allergens. Resolves spontaneously

Management

without treatment within 24-36 h.

• Epilate, electrolysis and cryotherapy trichiasis.

• Topical lubricants.

Superior limbic keratitis (SLK)

• Surgery: anterior lamella reposition.

Symptoms

Redness, burning, grittiness, photophobia and frequent blinking.

Pterygium (see Chapter 14).

Signs

Dry eyes

Bilateral superior conjunctival punctate stain with fluorescein and

Idiopathic dry eyes

rose bengal. The superior limbal conjunctiva is swollen and there

Symptoms

may be fine tarsal conjunctival papillae.

Gritty, sandy, burning dry eyes with reflex tear flooding

(hypersecretion).

Treatment

Treatment is with intense topical lubricant drops.

Signs

Poor tear film, interpalpebral punctuate epithelial staining, and

Ocular cicatricial pemphigoid (OCP)

poor wetting on litmus paper (Schirmer’s test).

This severe and fortunately rare conjunctival disease has an insidi-

ous onset with redness, grittiness and photophobia (early stages).

Management

Later there is cicatricial entropion, severe dry eye, corneal scarring

• Vigorously treat any meibomianitis and blepharitis.

and opacification. There is conjunctival fornix loss with sym-

• Artificial tears without preservatives and carbomeric gels.

blepharon and reduction of eye movements. Other mucous mem-

• Punctal occlusion can be done.

branes may be involved (e.g. mouth, nasal mucosa). Treatment is

with systemic immunosuppression, e.g. dapsone.

Sjögren’s syndrome

Hypofunction of the exocrine glands affecting the lacrimal and

salivary glands and the gastrointestinal tract. It affects women in

KEY POINTS

90% cases, with onset between 35 and 55 years. There is severe fa-

• Blepharitis is a common cause of red-rimmed, itchy eyes.

tigue, dry eyes, nose, throat, dental caries and digestive problems.

• Use topical lubricant drops (hypromellose) for dry eyes.

Vision can be impaired from epithelial damage and subsequent

• Excise pterygium only if encroaching onto the cornea and visual axis.

conjunctival and corneal scarring. Primary Sjögren’s syndrome is

Common conditions affecting the external eye 65

Aims

Treatment of epithelial disease is with antiviral medication (e.g.

1 Outline the basic anatomy of the cornea.

aciclovir topically and/or systemically). Judicious use of topical

2 Signs and symptoms of corneal disease.

corticosteroids for disciform keratitis.

3 Describe common disease processes involving the cornea.

WARNING

Corneal clarity

Steroid drops. Do not give steroid drops in the presence of active epithelial

The cornea is a clear because it has a highly organized structure of

disease as may cause ulceration and blindness.

collagen fibrils, it is free of blood vessels and allows the passage of

light in an organized way so a clear image may be focused on the

2 Herpes zoster ophthalmicus

retina. The corneal layers all contribute to its function. The en-

This affects the Vth cranial nerve with segmental skin vesicles and

dothelial cells actively pump out fluid from the stroma. A healthy

erythema which includes the upper eyelid.The rash does not cross

tear film (with all its constituent layers) and eyelids are vital to

the forehead midline. There is associated headache, malaise and

maintain corneal integrity and clarity.

fever. There is follicular conjunctivitis with variable involvement

Disturbance of the eyelids, conjunctiva or tear film may lead to

of the cornea —multiple epithelial pseudodendrites and anterior

corneal problems including ulceration. If the disease is severe,

stromal infiltration —responsive to topical corticosteroids. In-

corneal scarring with vascularization may lead to reduced vision

creased risk in immunocompromised patients, e.g. HIV.Treatment

and in rare cases to corneal perforation requiring surgical

is with systemic antivirals.

management. Corneal anaesthesia (Vth nerve palsy) predisposes

Inflammation

to severe keratitis.

Peripheral necrotizing keratitis

Corneal disease

This is related to an underlying systemic vasculitis, e.g. rheumatoid

Keratitis

arthritis, systemic lupus erythematosis or Wegener’s granulomato-

General term used to denote inflammation of the cornea from in-

sis. Peripheral destruction of corneal tissue is secondary to an is-

fection and inflammation.

chaemic microvasculitis in the adjacent scleral and conjunctival

Symptoms

vessels or it is mediated immunologically by blood-borne factors

or matrix metalloproteinases secreted into the tears. This patho-

Pain and photosensitivity (maybe absent in herpetic disease due

to corneal hypaesthesia), reduced visual acuity and/or discharge.

logical process is exacerbated by secondary Sjögren’s syndrome.

Treat the underlying disease process with systemic immunosup-

Signs

pression.Treat corneal perforation conservatively with tissue glue,

Reduced Snellen visual acuity and circumcorneal injection —a

bandage contact lenses or corneal grafting.

red, inflamed eye, presence of staining on fluorescein drop instilla-

tion, visible corneal infiltrate with or without anterior chamber

Corneal dystrophies

These are hereditary and occur at any level in the cornea —epithe-

hypopyon and blepharospasm.

lial, stromal and endothelial. With severe corneal dystrophies,

Infections

corneal grafting may be required to restore vision, although dys-

Bacterial keratitis

trophic changes often recur in the grafts.

Secondary to minor trauma (corneal abrasion or contact lens

Fingerprint and map-dot corneal epithelial dystrophies cause

wear). Treat as an emergency.

acute painful recurrent corneal erosions, particularly on waking.

A variety of bacteria may be responsible. Pseudomonas is com-

The most common corneal dystrophy, which is potentially sight

mon in contact lens-related keratitis and is rapidly destructive.

threatening, is keratoconus —associated with Down’s syndrome,

There is rapid corneal opacification and melt over less than 24 h.

disorders of collagen metabolism, atopic eye disease or idiopathic.

Rapidly identify the infective agent by C&S intensive topical

Keratoconic patients require special fit contact lenses and, if

antibiotics. Severe infections can lead to corneal perforation, en-

needed, corneal grafting. (See Chapters 31 and 32)

dophthalmitis and loss of vision.

Other dystrophies include lattice dystrophy, with deposition of

Acanthamoeba keratitis

amyloid in the corneal stroma, and inherited disorders of corneal

Acanthamoeba causes prolonged corneal infection. It is associated

metabolism (e.g. granular and macular dystrophy).

with poor contact lens hygiene —especially tap water in lens clean-

Fuchs’ endothelial dystrophy results in corneal clouding be-

ing —and with daily wear soft contact lenses. Characterized by se-

cause of endothelial pump failure. It causes a painful bullous

vere pain.

keratopathy, which is treated with a bandage contact lens and

Diagnosis may require corneal biopsy and histological assess-

eventual penetrating keratoplasty.

ment. Look for a corneal Wessely ring using the slit lamp.

Corneal neoplasia

Chronic infection with acanthamoeba cysts deep in the corneal

Although rare, conjunctival-corneal intraepithelial neoplasia

stroma may cause scarring requiring corneal graft.

(CCIN) and squamous carcinoma are important conditions. They

Viral keratitis

are more common in fairer-skinned individuals in hotter climes

1 Herpes simplex types 1 and 2

and immunocompromised patients with HIV. Needs to be treated

Epithelial disease — dendritic ulceration.

with excision or local destructive procedures.

Stromal disease — disciform keratitis

KEY POINTS

• immune mediated, presenting as a disc-shaped area of

corneal oedema, hence the term disciform;

• The healthy cornea is avascular and transparent due to endothelial pump.

• Topical steroids may worsen dendritic keratitis and should never be used.

• stromal necrosis may result in scarring with vascularization

reducing corneal sensation, clarity and vision.

• Bacterial keratitis in a contact lens wearer is an emergency.

Common conditions affecting the cornea 67

31 Therapeutic contact lenses

Soft contact lenses are very fragile. Bandage soft contact lenses are used in small perforation and bullous keratopathy

Epithelial

Endothelial cell

Bullous

bullae are

'pump' failure

keratopathy

painful

Thickened

oedematous

stroma

Tight lens syndrome

Contact lens too

tight at limbus

Epithelial oedema

- lack of oxygen

Oedematous

red limbus

Cosmetic contact lens

Hand-painted contact lens

- may have painted black pupil

Hypopyon ulcer

if corneal scar or a clear

window left if iris

abnormality

Unsightly

corneal

scar or iris

abnormality

Aims

Therapeutic bandage contact lenses

1 Medical indications for contact lenses (CL).

These are soft contact lenses with several functions.

2 Complications of contact lens wear.

Protection of normal epithelium

Contact lenses are an excellent alternative to glasses.They are also

• Trichiasis —to prevent lashes from rubbing the cornea.

widely used therapeutically in corneal disease. They are fitted for

• Lid margin deformation, e.g. lower lid entropion with lashes

each patient based on the steepness and diameter of the cornea.

touching the cornea, as temporary relief until surgery can be

The types of lenses (hard, gas permeable hard, etc.) and materials

performed.

used are summarized in Chapter 9.

• Protection of corneal graft epithelium.

• Dry eye, e.g. pemphigoid and Stevens-Johnson syndrome.

Keratoconus

• Exposure keratitis —following seventh nerve palsy.

In keratoconus, (GPH) CL are used. Some soft CL are suitable too

• To protect the cornea if there are sutures on the lid margin or

in the early stages. Once the corneal curvature is very ‘steep’ either

under the eyelid, abrading the cornea. Use until sutures dissolve or

GPH lenses are used or eventual corneal graft (see Chapter 32).

can be removed.

68 Sub-specialty —External eye disease

Healing abnormal epithelium

• Three and 9 o’clock staining (drying of corneal surface, abnor-

• Corneal epithelial dystrophy, e.g. Cogan’s microcystic epithelial

mal blink).

dystrophy, Meesman’s dystrophy, Reis-Buckler’s dystrophy and

• Inferior corneal stain (incomplete blinking).

map-dot or fingerpoint dystrophy.

• Dimple veil (static air bubble under lens).

• Chronic corneal ulcers —due to herpes simplex or vernal

• Overwearing syndrome (mechanical and metabolic factors).

keratoconjunctivitis.

• Abrasions and erosions.

Biological activity

• Filamentary keratitis —also rapid relief of the discomfort

The presence of a CL acting as a biological active surface can

caused by the corneal filaments.

cause several syndromes:

• Chemical, thermal and irradiation burns —high water content

• Toxic keratopathy (proteolytic enzyme —the chemical preser-

lenses may be useful to restore normal epithelialization.

vative in the cleaning solutions).

• Thiomersal keratopathy (the preservative in CL solutions

Moulding and splinting

or instilled eye drops acts as a hapten causing a delayed

• Post keratoplasty (corneal grafting) —to flatten and reposition

hypersensitivity response).

the graft when lifting or displacement of graft occurs.

• Giant papillary conjunctivitis

(multifactorial aetiology —

• Wound leaks —small corneal perforations need tight fitting;

immune response to antigenic proteins on lenses and mechanical

post-trabeculectomy bleb leaks need large lenses to cover the

effects of lens edge) causes red sticky eye.

leak.

• Sterile corneal infiltrate —inflammatory response in absence of

infecting organism, hypersensitivity to disinfectants and bacterial

Pain relief

products as well as lens fit are aetiological factors.

• Bullous keratopathy —CL help to alleviate pain by covering ex-

posed nerve endings.

Microbial keratitis

• Postrefractive surgery —PRK and LASEK for pain relief and

This is caused by a complex interaction of various factors and in-

wound healing. See Chapter 32.

creased ocular susceptibility and exposure to pathogens, associ-

ated with Pseudomonas, Staphylococcus and Acanthamoeba

Complications of contact lenses

(ubiquitous free-living protozon).

Corneal physiology

The constant metabolic activity in the cornea maintains trans-

Guidelines for managing microbial conjunctivitis

parency, temperature, cell reproduction and the transport of tissue

Emergencies are a routine occurrence in CL practice.

materials. The main nutrients are glucose, amino acids (from the

aqueous humour) and oxygen (from the tear film by diffusion

WARNING

when the eye is open and from the tarsal conjunctiva when the

In a contact lens wearer corneal and conjunctival complications are due to

eyelids are closed). Without oxygen there is hypoxia or anoxia.

contact lens wear until proved otherwise.

Hypoxia and anoxia

There are virtually no lenses available that fully meet the oxygen

requirements of the cornea, and there is no CL as physiological or

• Leave the lens out —Inflammatory symptoms of lens-related dis-

oxygen permeable as having no CL on the eye!

ease respond within a few days of ceasing lens wear.

One of the first important effects of hypoxia (which the patient

• Exclude microbial keratitis.

is unaware of) is a drop in corneal sensitivity. Anoxia causes

• Do not treat a red eye with steroids when there is a corneal ulcer.

corneal swelling, especially of the epithelium. If there is not

enough oxygen available to convert glucose, by the means of gly-

Advice for patients

colysis, into energy, the waste product (lactic acid) is allowed to

Maintain a high standard of CL hygiene. Lenses should be cleaned

diffuse and build up in the stroma. Sufficient osmotic pressure is

and disinfected each time they are removed. Avoid overnight

created to allow water to be drawn into the stroma faster than the

wear! Have back up spectacles! Leave lenses out when adverse

endothelial pump can remove it, so eventually corneal epithelial

symptoms or a red eye develops.

and stromal swelling occurs.

Lack of oxygen results in:

Feel good —look good —see good, if these critieria are not met the patient

• Acute epithelial necrosis.

should seek help.

• Microcystic epitheliopathy.

• Epithelial and stromal oedema.

• Corneal neovascularization.

KEY POINTS

• Use bandage CL for corneal protection, to aid healing, splinting and pain

Anatomical effects

relief.

Anatomical effects result in:

• Anoxia causes corneal swelling, cloudiness and pain.

• Tight lens syndrome.

• Beware bacterial contact lens complications!

• Corneal abrasions (foreign bodies).

Therapeutic contact lenses 69

32 Corneal and laser photorefractive surgery

Normal anatomy corneal limbus

Pterygium

Keratoconus

Cornea

Keratoconic

Iris

cornea

Invasive

Corneoscleral

pterygium

junction

Central core

Thinned

Conjunctiva

Fibro-

corneal

vascular

Stromal

Lens

apex

growth

Kaiser-Fleischer

(K-F) ring seen on

slit lamp

Pterygium surgery

Graft

site

Keratoglobus

Wide ectasia

- entire

ectasia

Kaiser-Fleischer

very thin

ring

Pterygium

Conjunctival

dissected off cornea

autograft

and sclera

Corneal topography scan showing shape of a keratoconic cornea

Corneal surgery - penetrating keratoplasty (CPK)

Approximately 7mm diameter

diseased cornea trephined out

Discard

Full-thickness corneal graft

sutured in

Diseased host

cornea

Clear donor cornea

Refractive laser surgery techniques: excimer laser uses

LASIK = LASer in situ keratomileusis

1 Cut a superficial flap with the microkeratome

Myopia

Effect of refractive surgery

2 Laser treatment to remodel the cornea

3 Replace the hinged flap

4 Place a postoperative contact lens on cornea

Photorefractive

LASIK

keratectomy (PRK)

Light focused

Flattens central cornea - light

anterior to retina

is focused further posteriorly

Hypermetropia

Laser applied

after epithelial

after partial

debridement

thickness flap

elevated

Flattens peripheral

Flattened anterior corneal

cornea - light is

DANGER

curvature in myopia

focused further

Laser

hazard

anteriorly

70 Sub-specialty —External eye disease

Aims

Wavefront technology enables precision planning for each individual.

1 Management of keratoconus.

2 Principles of corneal surgery.

Photorefractive keratectomy (PRK)

3 Know about current laser techniques.

Excimer laser ablation reshapes the anterior corneal surface after

manual debridement of the epithelium. >10 years’ track record.

Cornea

• Suitable for low refractive errors (-1 to -6D).

The healthy cornea is clear, tough and free of blood vessels or

• Disappointing for hypermetropia.

opacification and acts as an important refractive surface. Corneal

• Bandage contact lenses as eye painful for 48 h.

clarity is dependent on the integrity and normal functioning of all

• Variable slow healing and remodelling over months .

of its 5 cellular layers (see Chapter 30). Of particular importance is

• Quality of vision —temporary haze common after treatment.

the corneal endothelium, a single cell layer of non-mitotic cells

• Regression can occur in higher degrees of myopia (>-10D).

that maintains the cornea in a state of partial ‘dehydration’ and

• Recurrent erosions are a complication.

hence transparency through the use of cellular metabolic ‘pumps’.

When that pump fails, the stroma swells and becomes hazy, e.g.

Laser-assisted in intrastromal in situ keratomileusis (LASIK)

bullous keratopathy (see Chapter 31) requiring bandage CL or

A partial thickness corneal hinged epithelial ‘cap’ is raised and the

full thickness corneal graft (penetrating keratoplasty, PK).

excimer laser ablation is applied to stromal tissue below this, after

Keratitis causing corneal scarring can require PK. In order for

which the ‘cap’ is replaced. <10 years’ track record.

the graft to take, the host cornea should not have many blood ves-

• Suitable for higher degrees of myopia with less risk of regres-

sels, which could contribute to corneal graft rejection, and should

sion (up to -10D).

have near or near normal sensation. A partial thickness corneal

• Disappointing for hypermetropia.

graft is a lamellar keratoplasty.

• No haze.

• Best visual acuity achieved more rapidly than PRK.

Corneal diseases

• Dry eye for a few months.

Keratoconus

This common corneal dystrophy is a chronic progressive disease

Laser epithelium keratomileusis (LASEK)

characterized by thinning, cone formation and irregular myopic

This is large optical zone corneal surface excimer laser ablation.

astigmatism (see Chapter 30). The criteria for diagnosis are steep

The epithelium is treated with 15% alcohol for 20 s and is pre-

keratometric readings with irregular light reflexes on the corneal

served or delaminated with a microkeratome and is later replaced.

surface seen with the keratoscope and corneal topography.

This is the newest technique with a short track record, 5 yrs.

Early management is with SPH CL, and late management with

• A bandage contact lens is worn for 3-4 days whilst the epitheli-

PK.

um heals.

• There is speedy healing because the epithelium is retained.

Pterygium

• Mild pain only.

Microscopic lamella excision is needed if it encroaches on the vi-

• Good for astigmatism.

sual axis (See Chapter 14.)

• Excellent for myopia

6D, good for myopia -6 to

10D, all-

right for myopia -10 to -12D and for hypermetropia up to +4D.

Corneal neoplasia (See Chapter 30)

• Studies have limited follow-up data, often <2 years.

Corneal surgery

• Less haze risk than in PRK.

Corneal grafting

Who can have laser refractive surgery?

From human donor material. Donor eyes are stored in eye banks

• Patients should be >21 years, have a stable refraction, not

e.g. in London, Bristol, Manchester and Dublin. Donors are

pregnant and have no keratoconus, cataract or glaucoma.

screened for many contagious diseases including HIV.

• They should not be on systemic steroids.

Indications

• Patients should have realistic expectations and have been

• Visual rehabilitation following scarring, dystrophic changes or

warned of potential side effects of haze, night time glare, ghost-

endothelial dysfunction resulting in loss of corneal clarity.

ing images, starburst around lights, dry eye and risk of macular

• Restoration of structural integrity following perforation.

haemorrhage.

• Alleviation of pain in intractable corneal disease without visual

• It is also essential that patients are warned that intraocular pres-

potential, e.g. bullous keratopathy.

sure and A-scan/biometry measurements cannot be made accu-

rately after refractive surgery.

Refractive surgery

Surgery and/or laser is used to reshape the main refractive surface

WARNING

of the eye, (anterior corneal surface), and to bring light rays in

1 Corneal refractive surgery can have serious, potentially sight-threatening

focus on the retina without the need for glasses or contact lenses.

complications as with any ocular surgery.

The main indication is myopia.

2 Lasered donor eyes are not accepted for corneal grafting.

There are three methods of laser, in all of which the excimer

3 Refractive surgery effects may regress with time.

laser is used to correct myopia, hypermetropia and astigmatism

under local anaesthesia.

KEY POINTS

In myopia the corneal surface is flattened so that the image fo-

• A healthy corneal endothelium is essential for corneal clarity.

cuses onto the retina. The effect in hypermetropia is not always

• Corneal grafting is successful particularly in keratoconus patients.

stable.

• The main indication for laser refractive surgery is myopia.

Corneal and laser photorefractive surgery 71

33 Cataract assessment

Anatomy

Definition

The lens is crystalline with an inner nucleus of older inactive cells and an outer cortex, the whole

Cataract: Opacity of the lens of the eye,

being encapsulated. The epithelium is active metabolically, it synthesizes protein for lens fibres,

which occurs when fluid gathers between the

transports amino acids and maintains a cation pump to keep the lens clear. At the equator of

lens fibres. The refractive index alters and

the lens, epithelial cells differentiate into lens fibres, which lose their organelles and ability for

causes light scatter with resultant blurred

aerobic metabolism

vision. Acquired lens changes occur in 95%

Zonule filaments suspend the lens ciliary processes to the ciliary muscle. When the muscle

of people over 65, however, not all these

contracts the filaments relax allowing the lens to become more convex with a shorter focal length

people will require cataract surgery

for reading

Diagram of normal anterior segment

Close up of normal lens cross-section

Lens with cataract

Posterior

Equator

Capsule

Cortical

Cortex

epithelium

subcapsular

Embryonic

segment

Vitreous

Nuclear

nucleus

Lens fibres

(nucleosclerosis)

humour

Lens

New lens fibre

Cornea

Zonule

production

Posterior

Ciliary

subcapsular

Corneo-

Equator

process

Posterior

scleral limbus

Zonules

capsule

Sclera

Causes of cataract

• Old age (commonest)

Slit lamp view of nucleosclerosis

• Associated with other ocular and systemic diseases (diabetes,

uveitis, previous ocular surgery)

• Associated with systemic medication (steroids, phenothiazines)

• Trauma and intraocular foreign bodies

• Ionizing radiation (X-ray, UV)

• Congenital (dominant, sporadic or part of a syndrome, abnormal

galactose metabolism, hypoglycaemia)

• Associated with inherited abnormality (myotonic dystrophy,

Marfan's syndrome, Lowe's syndrome, rubella, high myopia)

Biometry: intraocular lens power calculation

The desired implant should produce a sharp image

on the retina. Since each eye has a different corneal

Natural lens

curvature and axial length, the implant size has to

15D

be measured preoperatively in each patient. The

Cornea

optics of the eye are such that light is refracted by

43D

the cornea (effective power of 43D) and by the

natural lens (effective power 15D), both of these

together give the total power of the focusing

components of the eye. A special equation is used

to calculate the intraocular lens power, which is

usually in the range of 19-22D, with some very

Optics of cornea

short-sighted eyes needing lower powers and long-

and lens refract light

sighted eyes needing higher powers for clear

focused distance vision

72 Sub-specialty —Corneal, refractive and cataract surgery

Aims

TIP

1 Anatomy of the lens.

Pupils are normal if there is no other ocular or optic nerve disease.

2 Causes of cataract.

3 Symptoms and signs.

4 Treatment of cataract.

Treatment

• Cataract alters the refractive power of the natural lens so a

change in glasses prescription may allow good vision to be main-

tained. The eye may become more myopic (lenticular-induced

myopia) or hyperopic. The legal requirement for driving a car in

Cataract is the most common cause of blindness in adults worldwide.

the UK is 6/10 in one eye. NB, the Snellen chart only has lines

corresponding to 6/9 and 6/12.

• If further changes occur in the lens, with increased disturbance

of the lens fibres, the visual acuity cannot be improved with

Symptoms

glasses and surgical removal of the cataractous lens is required.

• Reduced visual acuity (near and distant objects).

• Modern surgery involves removal of the lens fibres, which form

• Glare in sunshine or with street or car lights.

the nucleus and cortex of the cataract, leaving the posterior

• Distortion of lines.

epithelial capsule to hold the new artificial lens and keep the

• Monocular diplopia.

vitreous humour away from the anterior chamber.

• Altered colours (white objects appear yellowish).

• Not associated with pain, discharge or redness of the eye.

Preparation for cataract surgery

• Biometry: ultrasound measurement of the length of the eye and

Signs

keratometry to measure the curvature of the cornea and hence

• Reduced acuity measured on a Snellen chart or LogMar and

calculate the power of the implant to be inserted in the eye during

near vision chart.

surgery.

• An abnormally dim red reflex is seen when the retina is viewed

• Confirm that general health problems are stable, particularly

with an ophthalmoscope at arms length. Nuclear cataract causes a

hypertension, respiratory disease and diabetes.

central black shadow across the red reflex and cortical cataracts

• Some medication increases the incidence of haemorrhage.War-

cause black spoke-like shadows coming from the edge of the red

farin does not need to be stopped but the INR should be less than

reflex.

3. Aspirin may be stopped 1 week before surgery.

• Reduced contrast sensitivity can be measured by the

• Inform patients of expected outcome and the complications of

ophthalmologist.

surgery (informed consent).

• Only very dense cataracts causing severely impaired vision

cause a white pupil.

KEY POINTS

• After pupils have been dilated, slit lamp examination shows

• Cataract is common, it is one of the three main causes of blindness world-

whether the cataract is cortical, nuclear or posterior subcapsular

wide.

and allows fundus examination.

• Can occur at any age and in all races.

• Cataract in children is unusual but may be associated with a

• Effectively treated by glasses in the early stages and by surgery when more

white pupil, inability to fix on a target (e.g. a light) and the devel-

advanced.

opment of a squint.

Cataract assessment 73

34 Cataract surgery

An operating microscope is needed. In order to reach the lens, a small corneal

Model of eye showing anterior chamber depth

incision is made close to the limbus for the phaco-probe. It is important to

Epithelium

appreciate ANTERIOR CHAMBER DEPTH and to keep all instruments away

from the corneal endothelium, in the plane of the iris

Endothelium

chamber

depth

Corneoscleral

limbus

Phacoemulsification surgery

Phaco-probe

3. Foldable intraocular lens (IOL)

2.75 mm incision in cornea

Corneal incision

1. Keratome corneal incision

being inserted

Limbus

profile - self-sealing

sutureless wound

Paracentesis incision

Phaco-probe in lens

Capsulorhexis

Dilated pupil

Intraocular lens

Capsulorhexis edge

Intraocular lens

placed in bag

Anterior capsule

Iris

Ciliary body

Zonule

Posterior capsule

Anterior capsule

Capsulorhexis

edge

Intraocular in capsular

2. Phaco-probe sculpting lens

4. IOL unfolded in capsular bag

bag

nucleus

Steps:

New techniques

• Corneal incision 2.75-3.2 mm

Clear lens surgery - a novel lens refractive technique

• Viscoelastic to anterior chamber

• Capsulorhexis

Phacoemulsification is used for cataract surgery and also for CLEAR

• Hydrodissection

LENS surgery. Clear lens surgery is called lens refractive surgery and is

• Phaco removal of nucleus

increasingly being offered for presbyopia and high myopia. Technology for

• Aspiration of cortex

lens surgery is accelerating at a phenomenal speed

• More viscoelastic:

• A folded IOL is inserted under a cushion of viscoelastic fluid,

1. Clear lens IOL - the patient's lens is removed and an IOL of a different

which protects the corneal endothelium; the lens unfolds

power inserted. E.g. Prelex lens exchange - this is a special IOL which

spontaneously within the capsular bag

tilts with accommodation maintaining clear 'unaided' distance and near

• Viscoelastic removed and replaced with balanced salt solution

vision! Myopic patients having LASER corneal refractive surgery now

• Self-sealing wound

may opt for this when prebyopic!

• Subconjunctival injection of steroid and antibiotic

• Eyepad and protective eye shield

2. Phakic IOL - the patient’s clear lens is left in situ and a second lens

placed in front of it - used for myopia correction

Both these techniques have potential complications and the patient

needs to be fully informed before going ahead

74 Sub-specialty —Corneal, refractive and cataract surgery

Aims

the lashes. The drape is light and also covers the face —lifted up

1 Understand methods of anaesthesia and cataract removal.

from it as a small tent —to protect the face from irrigation fluids

2 Be able to explain cataract surgery to a patient.

used in the surgery, which are collected into a small bag at the side

of the head.

Microsurgical cataract surgery in developed countries has reached

a very high level due to the developments in microsurgical instru-

Small speculum

ments and intraocular lens design. There is controlled and precise

The eyelids are kept open by a combination of the drape and a

removal of part of the lens with the assistance of an operating

small wire speculum which does not cause the patient discomfort.

microscope. Part of the lens capsule is retained to hold the implant

within it.

TIP

Phacoemulsification lens surgery with small, foldable intraocular lens im-

Definitions

plants is the gold standard. It gives rapid visual rehabilitation with a low com-

Pseudophakia: An eye that has had a cataract removed and artifi-

plication rate.

cial intraocular lens implanted.

Aphakia: An eye that has had a cataract removed without an arti-

ficial lens inserted.

Surgery

Extracapsular cataract surgery is a technique in which the posteri-

Anaesthesia for cataract surgery

or capsule of the lens is retained, keeping the vitreous separate

from the anterior chamber of the eye. It may be small or large in-

cision surgery.

TIP

• Small incision surgery is by using phacoemulsification (phaco)

Most adult cataract surgery is done under topical or local anaesthesia. The pa-

to crumble the lens in the eye. Fragments are irrigated out auto-

tient may see bright lights and different colours, shadows of the surgeon’s

matically. A soft, foldable intraocular lens implant (IOL) can be

hands moving or complete darkness during surgery.

inserted through the small incision into the lens capsule (posterior

chamber IOL).This incision is usually sutureless, or a single suture

Local anaesthesia

is placed, which can be removed as early as 2 weeks after surgery.

• Topical (drops of proxymethocaine or amethocaine).

Phaco is the most commonly used technique.

• Subtenons using a blunt canula to administer 2 ml of lidocaine.

• Large incision surgery involves removal of the entire nucleus as

• Peribulbar injection to distribute 5-10 ml lidocaine within the

one piece; the soft cortex is aspirated and a rigid or soft implant is

orbit.

inserted. The corneal wound requires microsutures, which are

• Retrobulbar injection to direct 1-2 ml lidocaine within the mus-

removed as late as 8 weeks after surgery.

cle cone —now becoming less commonly used.

Implant power

Sedation

The IOL power is carefully calculated to take into account the pa-

Intravenous drugs may be given with local anaesthetics but are not

tients postoperative visual requirements. For instance, a myopic

preferred as the patient could drift off to sleep and then suddenly

person may prefer to remain slightly myopic after surgery so that

wake up with a jolt and move their head —undesirable in cataract

they can still read without glasses. Multifocal IOLs and accom-

surgery.

modative IOLs are increasingly being used.

General anaesthesia

Clear lens surgery for presbyopia

This is used for young and uncooperative patients.

Over the next few years an increasing number of people in their

fifties will have their lenses removed for presbyopia, in order to

Surgical technique for cataract removal

avoid having to wear reading glasses, and special accommodative

Patients have to lie supine so a microscope with a bright light and

IOLs will be inserted. Hence the number of people developing

good magnification can be positioned above them. The surgeon

cataract will be reduced.

works from the side or above the head, looking down the micro-

scope, using the red reflex from the retina to aid cataract removal.

KEY POINTS

• Microsurgery involving the replacment of the natural lens with an artificial

Draping

one.

Before surgery can start, the eyelids and lashes are covered with a

• Day-case procedure under local anaesthesia.

thin transparent plastic drape in order to keep contaminated

• Patient needs to be able to lie still and flat for 30 min.

lashes out of the surgical field. Staphylococci live in abundance on

Cataract surgery 75

35 Cataract surgery postoperative care

Early postoperative

Symptom

Sign

Treatment

problems

Raised intraocular

Pain, deep ache,

Hazy cornea

Ophthalmologist needs to measure pressure and

pressure

blurred vision

treat with systemic acetazolamide 250 mg

2-4 times daily (1-2 days) and glaucoma drops

Leaking incision

Poor vision

Siedel positive

Ophthalmologist may need to suture the wound in

with fluorescein

the operating theatre. If the anterior chamber is

deep and the ocular pressure is normal, a soft

contact lens may be placed on the eye. Daily review

is required

Subconjunctival

Red eye. No pain

Diffuse redness on

Continue drops. Reinforce good technique for

Leaking wound - a positive

haemorrhage

the globe

instilling drops

Siedel test (trabeculectomy

bleb leak)

Corneal oedema

Poor vision

Hazy cornea

Ophthalmologist needs to exclude raised pressure

and increase topical steroid drops

Epithelial erosion

Gritty, watering

Fluorescein staining,

Continue drops, reassure. Monitor carefully to

(conjunctiva or

may have injected

exclude early infection

cornea)

bulbar conjunctiva

Conjunctivitis

Pain, redness with

Swollen, red tarsal

Prescribe different antibiotic, (e.g. ofloxacin) to be

mucopurulent

conjunctiva while

used 2 hourly. Frequent review to confirm no

discharge

maintaining good

progression to endophthalmitis

vision

Sight-threatening

Symptom

Signs

Slit lamp signs

Treatment (by ophthalmologist)

postop problems

observed

observed by

requiring urgent

with pen

ophthalmologist

Hypopyon indicates

treatment by

torch

endophthalmitis

ophthalmologist

Endophthalmitis

Painful, red eye

Red eye with hazy

Flare, cells and

URGENT in-patient management.

usually with a

cornea. A relative

and hypopyon in

Intensive topical broad spectrum

mucopurulent

afferent pupillary

antibiotics (drops). Requires

discharge and

defect indicates

chamber

aqueous and vitreous sample for

poor vision at

serious visual

microscopy, culture and

day 3-5

damage

sensitivity

Fibrin plaque - intense

Macular oedema

Poor vision

Normal anterior

Slit lamp fundus

Treated with anti-inflammatory drops

(retina)

during first

segment of the

examination and

(steroid and non-steroidal), steroid

postoperative inflammation

in endophthalitis

60 days after

eye

fluorescein angio-

injection around the eye, systemic non-

surgery

graphy show

steroidal anti-inflammatory, e.g.

increased fluid in

neurofen

the retina around

the fovea

Opacity of posterior

Gradual

White eye with no

Posterior capsule

Make a hole in the capsule using a YAG

part of the original

deterioration

external

hazy or white.

laser (clinic procedure requiring

epithelial capsule of

of vision, as

abnormality. Red

Implant is

anaesthetic drops). Cornea, anterior

the natural lens

though

reflex from fundus

unaffected

chamber and implant are not affected

(can occur between

cataract is

may be obscured

by the laser

1 month and 2 years

reforming

after surgery)

Definitions:

Endophthalmitis = infection and inflammation involving the whole of the

Cystoid macular oedema (CMO)

contents of the eyeball

- typical colour fundus and

IOP = Intraocular pressure

fluorescein angiographic

YAG laser capsulotomy = laser treatment for posterior capsular opacity

appearance

Siedel test = fluorescein test to look for wound leakage of aqueous humour

YAG capsulotomy hole made

in thickened posterior capsule

from the eye

76 Sub-specialty —Corneal, refractive and cataract surgery

Aims

Undesirable postoperative events (complications)

1 Awareness of normal and undesirable early and late postopera-

Watering and a foreign body sensation are common after surgery.

tive events.

Usually the patient can be reassured, but the possibility of infec-

2 Recognize postop complications from history.

tion —endophthalmitis —the most important sight-threatening

3 Use of pen torch and fluorescein drops to detect a leaking

complication, must be considered. This is an acute sight-threaten-

wound and see hypopyon.

ing postoperative event that requires urgent admission and treat-

ment. Its onset is usually 4-5 days after surgery. Symptoms include

Routine postoperative management

worsening vision and pain.

Patients use steroid and antibiotic drops four times daily for 2-4

See Tables for early and late complications.

weeks after surgery. During that time they can read, take gentle

exercise, shop, shower or bath and wash their hair carefully. The

implant inserted at surgery normally gives them clear vision for

KEY POINTS

distance (e.g. TV, buses) but they will need to wear reading glasses

• Over 97% of cataract surgery is successful.

(approximate prescription +2.5D); these can be prescribed from

• Endophthalmitis is the most serious postoperative complication.

2-4 weeks after phacocataract surgery. Some patients have a

• Sympathetic ophthalmia affects the other eye —rare <0.01%.

multifocal implant inserted so they are less dependent on glasses

for reading.

Reading glasses

Patients who have had phacocataract surgery usually have good vision from

the first postoperative day and can be tested for spectacles (refraction) for

reading 2 weeks after surgery.

In contrast, patients who have had large excision extracapsular cataract

surgery have corneal sutures, which are not removed for 2-3 months. Only

after these have been removed are reading spectacles prescribed, i.e. there is

a longer rehabilitation period.

Cataract surgery postoperative care 77

36 Glaucoma—the basics

Anatomy: aqueous production, drainage and resistance to flow

Intraocular pressure (IOP) is due to the production of aqueous humour

by the ciliary body. Aqueous flows forward over the anterior surface of

Cornea

the lens, through the pupil and drains through the trabecular

meshwork into Schlemm’s canal. The alternative uveoscleral pathway

drains 10% of aqueous

Iris

Ciliary

Sites of blockage:

1 Ciliary block

body

2 Pupil block

Lens

3 Pre-trabecular - neovascular membrane or cellular debris

4 Trabecular

5 Post-trabecular - elevated episcleral venous pressure

Anatomy: Normal and cupped optic nerve heads in chronic primary open angle glaucoma

Disc

Cup

(a) Normal disc

(b) Glaucoma:

focal notch

diffuse cup

Cup disc ratio

enlargement

approx 0.3

Cup disc ratio

approx 0.8

IOP and glaucoma risk

Normal population

Acute angle-closure glaucoma

distribution of IOP

Glaucoma risk

Glaucoma

risk

NTG

NTG = Normal tension

15.5

21.0

30.0

glaucoma

IOP (mmHg)

Aims

Classification

1 Understand the group of conditions classed as glaucoma.

The glaucomas are a diverse group of eye conditions (at least 60

2 Know the symptoms and signs of acute angle-closure glaucoma

types), which can be divided into diagnostic groups in the follow-

to enable urgent referral for treatment of this ophthalmic

ing way:

emergency.

1 Defined by absence or presence of causative factors: primary or

secondary.

Definitions

2 Defined by the anatomy of the drainage angle: open angle or

Glaucoma: A multifactorial optic neuropathy with characteristic

angle closure.

acquired loss of optic nerve fibres. Commonest cause of irre-

3 Defined by speed of onset: acute or chronic.

versible blindness in the world, affecting 2% of people over 40

4 Defined by age of onset: congenital, juvenile or adult.

years of age, and 4% of people over 70 years.

5 Defined by level of IOP: normal tension glaucoma (characteris-

Intraocular pressure (IOP): The ‘normal’ range of IOP varies be-

tic glaucomatous optic neuropathy with IOP in the normal range)

tween 10 and 21 mmHg but there is no absolute limit. Elevated

or ocular hypertension (IOP above the normal range but no glau-

IOP is a major risk factor for the development of glaucoma.

comatous optic neuropathy).

Skills to obtain

Chronic primary open-angle glaucoma (POAG)

Use of direct ophthalmoscope to evaluate optic disc colour and

This is by far the commonest form of glaucoma in Caucasian and

cup : disc ratio.

Afro-Caribbean populations.The exact mechanism of pathogene-

78 Sub-specialty —Glaucoma

sis is unknown, but various factors are implicated including

Treatment

elevated IOP and altered vascular supply to the optic nerve.

Urgent treatment needed to prevent permanent loss of vision.

Genetics also plays a role, with nine loci in the human genome

• Treat medically (topical and systemic) to bring down IOP and

known to be associated with glaucoma. Risk factors include ele-

break attack.

vated IOP, family history and Afro-Caribbean descent.

• Prevent further attacks with YAG laser iridotomy or surgical

peripheral iridectomy (in both eyes).

Symptoms

• The second eye is treated prophylactically to prevent later

Usually asymptomatic until disease is advanced with advanced

AACG (see Chapter 38).

optic disc cupping, when peripheral field defect may be noticed

and central vision lost. ‘Tunnel’ vision is not noticed early on.

Secondary glaucoma

Multiple causes including uveitis, rubeofis and trauma.

Signs

• Usually raised IOP >21 and <40 mmHg.

Treatment

• Normal open angle on gonioscopy.

Treat the cause and control IOP.

• Characteristic optic disc changes with gradual thinning of the

neurosensory rim superiorly and inferiorly with time, nerve fibre

Chronic angle-closure glaucoma

layer defect, optic disc rim notching and cupping, cup : disc ratio

Younger age group with intermittent angle-closure symptoms.

enlarged and/or asymmetrical.

• Visual field changes on automated fields analysis with charac-

Treatment

teristic arcuate scotoma.

Laser peripheral iridotomy.

Treatment

Congenital glaucoma / infantile glaucoma / buphthalmos

• Medical with daily or twice daily topical drops, laser and surgi-

Occurs in infancy, and can be unilateral or bilateral. Primary or

cal options (see Chapter 38 for details).

associated with ocular malformation or systemic syndrome, e.g.

• Most patients are maintained on regular topical medication

Sturge-Weber. Can go blind if not detected and treated.

with monitoring of disc appearance and visual field analysis.

Symptoms

Acute angle-closure glaucoma (AACG)

Watering photophobic eyes.

Commoner in older, hypermetropic people. Commonest glau-

coma in Chinese people.

Signs

• Large eyes (myopic) —buphthalmos.

Symptoms

• Diameter of corneas wider than normal.

• Sudden onset of severly painful red eye.

• Reduced vision.

• Blurred vision.

• Clouding of corneas.

• Halos around lights.

• Linear tears in Descemet’s membrane.

• Headache.

• Raised IOP.

• ±Nausea and vomiting.

• ± Red eyes.

Treatment

WARNING

• Specialist medical management by paediatric ophthalmologist.

Patients with AACG can go blind if the glaucoma is unrecognized and

• Then various surgeries, goniotomy, trabeculotomy or tra-

untreated.

beculectomy.

• Goniotomy is the first choice and may have to be repeated.

Signs

• Reduced visual acuity.

KEY POINTS

• Brick red eye.

• Normal range of intraocular pressure is 10-21 mmHg.

• Hazy cornea (corneal oedema).

• Primary open-angle glaucoma is the commonest form.

• Vertically mid-dilated fixed pupil.

• Acute angle-closure glaucoma occurs in older persons and is usually

• Very high IOP, that can be felt digitally.

painful.

• Closed iridocorneal angle on gonioscopy.

Glaucoma—the basics 79

Aim

Monitoring

Understand how glaucoma is diagnosed.

Once a patient has been diagnosed and started on treatment, the

same techniques are used at regular intervals to assess for pro-

History taking

gression. Finding the correct treatment to prevent progression is

Apart from acute angle-closure glaucoma, most forms of glau-

dependent on these same examination techniques.

coma are asymptomatic until very advanced optic nerve damage

has occurred. A positive family history of glaucoma and myopia

Screening

are important risk factors in the history.

Most forms of glaucoma are asymptomatic until very advanced

optic nerve damage has occurred. Treatment at this stage is often

Clinical examination

too late, so glaucoma patients may be actively sought out from the

1 Visual acuity. Reduced by advanced chronic glaucoma damage

community, i.e. screened. This is usually done by opticians, who

or acute angle-closure glaucoma.

assess IOP, visual fields and optic disc appearance. Two main

2 Ocular examination.

groups of people are screened:

• Slit lamp examination for anterior segment abnormalities

1 People with a family history of glaucoma, especially primary

associated with glaucoma.

open-angle glaucoma.

• Detailed assessment of optic disc. Ideally the optic disc is

2 All people over 40 will have IOP measured at a sight test.

photographed (conventional or with 3D scanning laser ophthal-

If an abnormality suggestive of glaucoma is detected in this

moscope) to enable detection of progression.

screening process, the person is referred to the hospital ophthal-

3 IOP measurement. Using Goldmann applanation tonometer.

mology department.

Measures force needed to flatten a defined area of cornea. This

force corresponds to intraocular pressure (IOP, measured in mm

Problems of glaucoma screening

of mercury). NB, low tension glaucoma has normal range IOP.

• People are missed if they do not attend opticians.

4 Visual field testing. Usually assessed with automated perimetry

• False positives are common because the initial assessment of

to allow efficient repeat testing to detect progression. Classic

field and disc is difficult.

defect is arcuate scotoma.

5 Gonioscopy. Used to assess the anterior chamber angle. Can not

be viewed directly so gonioprism lens is used —the optics of which

WARNING

allow visualization of the angle between the cornea and iris.

Some patients have low-tension glaucoma in which they have field loss and

Glaucoma is diagnosed if a glaucomatous optic neuropathy

cupped discs with normal IOP.

(typical optic disc and field changes) is found to be present. Other

parts of the examination help classify the glaucoma so appropriate

treatment can be given.

KEY POINTS

• Glaucoma screening by opticians helps detect primary open-angle

TIP

glaucoma.

Do not rely on IOP measurement alone for the diagnosis and monitoring of

• A family history of primary open-angle glaucoma is a risk factor for devel-

glaucoma as the IOP may be in the normal range, yet disc and field changes

oping glaucoma.

may be present.

• Automated visual field analysis is used to monitor visual field progression.

Detecting glaucoma 81

38 Medical and surgical treatment of glaucoma

Medical treatment

Glaucoma surgery

This is the first line of treatment for glaucoma

Laser or drainage surgery is indicated when there is

progression of glaucoma not controlled by medication.

Laser iridotomy prevents acute angle-closure attacks

Laser treatments

Peripheral iridotomy

Cyclodiode

Argon laser trabeculoplasty

Argon laser burns

Schwalbe's line

Trabecular meshwork

Ciliary body

Iris

Pupil

Surgical treatments

Trabeculectomy

Drainage devices/tubes

Bleb

Cornea

Iris

Diffuse bleb

Scleral flap

Sclerostomy

Bleb

Sclera

Pupil

Lens Zonules

Tube in anterior chamber

Aims

Medical therapy

1 Understand the aims of medical, laser and surgical treatment

Treatment is tailored to each patient’s findings —intraocular pres-

2 Be familiar with the different classes of drugs used to treat

sure (IOP), visual field and optic disc appearance —and their type

chronic open-angle glaucoma.

of glaucoma. Most patients with chronic open-angle glaucoma are

3 Manage a case of acute angle-closure glaucoma (AACG).

treated medically and do not require surgery to drain the aqueous.

The aim of medical treatment is to prevent progression of disc

cupping or visual field defect.

Treatment goal

To preserve patient’s sight throughout their lifetime with minimum side

effects.

• Treat to lower IOP. This is the main aim of current glaucoma therapy.

• Treat to increase ocular perfusion. Prevent low blood pressure (nocturnal

dips), treat vasospasm (calcium antagonists) and prevent arteriosclerosis.

Treatment options

1 Medical therapy.

2 Laser.

3 Surgery.

82 Sub-specialty —Glaucoma

Table of topical medical treatments

Class of agent

Method of action

Side effects

Examples (trade name)

Beta-blocker

Decreases aqueous humour

Bradycardia/heart block

Timolol (Timoptol)

production

Bronchoconstriction

Betaxolol (Betoptic)

Depression

Carteolol (Teoptic)

Impotence

Levobunolol (Betagan)

Miotic (parasympathomimetic)

Increases outflow through

Blurred vision

Pilocarpine

trabecular meshwork

Headache

Eye ache

Carbonic anhydrase inhibitor

Decreases aqueous humour

Malaise

Dorzolamide (Trusopt)

production

Depression

Brinzolamide (Azopt)

Metallic taste

Acetazolamide (Diamox), oral and i.v.

Alpha-1 agonist

Decreases aqueous

Allergy

Brimonidine (Alphagan)

production and increases

Dry mouth

Apraclonidine (Iopidine)

uveoscleral outflow

Fatigue

Prostaglandin agonist

Increases uveoscleral outflow

Increased iris pigment

Latanoprost (Xalatan)

Eyelash growth

Travoprost (Travatan)

Macular oedema

Docosanoid

Increases uveoscleral outflow

Allergy

Unoprostone (Rescula)

Nausea

Nasal congestion

Prostamide

Increases uveoscleral outflow

Allergy

Bimatoprost (Lumigan)

Adrenergic agonist

Increases uveoscleral outflow

Rarely used now

Epinephrine (Eppy)

Dipivinyl epinephrine (Propine)

Laser treatment

Treatment of AACG

• Peripheral iridotomy. Procedure of choice to prevent angle-

AACG requires medical, laser and surgical treatment. Immediate

closure glaucoma or after an acute attack has been broken with

treatment is medical to reduce the IOP and to break the attack of

medical treatment. A YAG laser hole in the iris allows aqueous

angle closure.

flow from posterior to anterior chamber.

• Intravenous carbonic anhydrase inhibitor

(acetazolamide

• Cyclodestruction. Diode laser (usually) to ciliary body to re-

500 mg) is used to halt the production of aqueous fluid.

duce aqueous production.

• Oral acetazolamide may also be needed for up to 24 h.

• Argon laser trabeculoplasty. Laser to trabecular meshwork to

• Pilocarpine may be needed to break the attack, but is not used

increase aqueous outflow.

intensively.

• Other topical agents will also help reduce the IOP (timolol or

Surgical treatment

iopidine).

• Peripheral iridectomy. Used in AACG when laser is not possible.

• To prevent further attacks: pilocarpine drops (2-4%) are used

• Trabeculectomy. Standard glaucoma surgery to filter aqueous

(not intensively) in both eyes to constrict the pupil as a temporary

from anterior chamber to subconjunctival space, used most com-

measure. Bilateral laser iridotomies (and occasionally surgical

monly for open-angle glaucoma. Antimetabolites such as 5-

irridectomy) must then be performed as a permanent prevention.

fluorouracil and mitomycin C are used to modulate conjunctival

• Rarely, trabeculectomy is required.

healing and improve success rates. Risks include cataract, hy-

potony, infection and bleb leakage.

KEY POINTS

Other surgical techniques

• Most primary open-angle glaucoma patients are treated medically, e.g. with

• Drainage devices/tubes. Silicone tube inserted into anterior

topical beta-blockers.

chamber and connected to subconjunctival silicone chamber to

• Trabeculectomy lowers the IOP by draining aqueous into a small sub-

drain aqueous. Used when trabeculectomy may fail, for instance in

conjunctival bleb from where the fluid is reabsorbed.

congenital glaucoma and some of the secondary glaucomas.

• Surgery is indicated for disease progression in primary open-angle

• Deep sclerectomy. Section of sclera and roof of Schlemm’s

glaucoma.

canal are excised. No penetration into anterior chamber so less

complications than trabeculectomy, but less IOP control.

• Viscocanalostomy. Deep sclerectomy with additional mechani-

cal opening of Schlemm’s canal by injecting high viscosity fluid.

WARNING

Acute angle-closure glaucoma (AACG) is an ophthalmic emergency.

Medical and surgical treatment of glaucoma 83

39 Retinal detachment

Ora serrata

Anatomy of retina

Sclera

Choroid (supplies

outer 2/3 of retina)

Macula

Retina

Ciliary body

Foveola

Fovea

Vitreous

humour

Retinal

/body

vessels

(supply inner

Optic nerve (composed

¹/3 of retina)

of ~ 1.3 million axons

coming from 1.3 million

rods and cones)

Floaters

Posterior vitreous detachment (PVD)

More noticeable on a sunny clear day against a blue sky,

or white snow, or a white wall/ceiling. They can be

Patient may see

On ophthalmoscopy:

particularly annoying when patients find that they get in

'dirt' or 'a cobweb'

the way of reading. They are common at any age.

or 'a fly'!

NB many people have floaters

Posterior vitreous detachment (PVD)

The vitreous gel 'jelly' separates from the posterior retina.

This also causes 'floaters' such as a Weiss ring and is

more common in older patients and myopics

WARNING

May see Weiss' ring

Vitreous body pulls away

Patients with PVD should be warned of the risk of retinal

floating in front of disc

from retina (to which it

tear and detachment - should they notice a sudden

is normally attached)

shower of floaters or new flashing lights or a shadow at

the edge of their vision, they should seek an urgent

ophthalmological opinion

Retinal detachment (RD)

On ophthalmoscopy:

May get small haemorrhage

Attached flat retina

Retinal tear

Tractional

Subretinal fluid

Macula

Bullous RD

overhanging

Pale detached retina

disc and macula

Vitreous

Tobacco dust

Tractional band from

Retinal hole

old perforation site

Detached retina

WARNING

Blood vessel on detached retina

If the macula is detached there is a risk

Attached flat retina

of permanent visual impairment

Optic disc

84 Sub-specialty —Vitreoretinal and medical retina

Aims

reous to enter the space between the retina and the RPE.This type

1 Understand significance of eye floaters.

of RD is known as a rhegmatogenous retinal detachment. Individ-

2 Types of retinal detachment.

uals with high myopia are at increased risk of this type of RD.

3 Principles of managing a retinal tear.

• Some inflammatory and neoplastic conditions can lead to

serous exudation from leaky blood vessels beneath the retina in

Posterior vitreous detachment (PVD)

the absence of a retinal break or hole, this is referred to as an

A PVD is when the posterior aspect of the vitreous body pulls

exudative retinal detachment.

away or separates from the retina and collapses towards the vitre-

• Fibrous or vascular membranes growing abnormally in the vit-

ous base. Noticed as a floating cobweb, ring or tadpole, which

reous (e.g. in patients with diabetes or who have had a penetrating

moves with eye movement.

eye injury) can contract and pull the retina away from the RPE.

This is known as a tractional retinal detachment.

Aetiology

• A tumour such as a malignant melanoma originating in the

• Trauma to the eye or head.

choroid behind the retina can elevate the retina, causing a solid

• Spontaneous —especially in myopic eyes. Onset can be gradual

retinal detachment. This can metastasize and needs urgent

or more acute, and is due to degeneration of the vitreous gel.

treatment.

Symptoms

• Photopsia (i.e. flashing lights) results from physical traction of

Rhegmatogenous RD presents with:

the retina —not necessarily indicating a retinal tear. The flashing

• Photopsia ± floaters.

lights are more noticeable in dim lighting.

• Followed by gradual blurring or loss of vision, which may start

• Floaters result from a small amount of haemorrhage which may

off as a shadow in the peripheral visual field. As the SRF spreads

occur, or the collapsed vitreous which casts a shadow on the

to involve the macula, the vision becomes very blurred.

retina.A ring shape (Weiss’ ring) may be seen or cobwebs or a tad-

• Other types of RD present with reduced vision.

pole shape.

Natural history of floaters

Signs

The majority of floaters from PVD are self-limiting, setting as

• Visual acuity may appear normal when macula on.

occasional floaters and becoming less noticeable. Only a small

• Reduced visual acuity may be due to macular SRF or may result

proportion of patients develop a retinal tear.

from a bullous RD falling in front of the macula.

• On slit lamp examination, ‘tobacco dust’ may be visible in the

Complications

anterior vitreous (these are red blood cells and/or RPE cells that

In up to 15% of patients who present with an acute symptomatic

have migrated into the vitreous from the tear).

PVD the detaching vitreous pulls a hole in the retina, which can

• Intraocular pressure may be reduced.

lead to a rhegmatogenous retinal detachment.

• Detached retina on fundoscopy —indirect ophthalmoscopy

with scleral indentation is the preferred method of viewing this. A

Management

three-mirror contact lens at the slit lamp can be used if a retinal

• Full retinal assessment is needed to rule out a retinal tear —

tear is likely to require laser treatment and not full surgery.

examine through dilated pupils. The periphery of the retina can

be seen on the slit lamp using a three-mirror contact lens. Indirect

Complications

ophthalmoscopy with scleral indentation is the best method of

• If the RD involves the macular area, the chance of regaining

mapping the retinal detachment and location of the retinal tear.

vision is very much reduced.

• If a simple retinal tear is present with minimal or no subretinal

• Recurrent RD carries the risk of subretinal membrane and sec-

fluid—use laser treatment to seal the tear and to prevent retinal

ondary tractional detachment.

detachment.

• No tear —reassurance only, no treatment is required.

Management

• Rhegmatogenous RD —use reattachment surgery: laser, cryo-

Retinal detachment (RD)

therapy plus explant or internal surgery with vitrectomy.

• An RD occurs when the retina is separated from the retinal pig-

• Exudative and solid RD —establish and treat the cause.

ment epithelium (RPE) by fluid (this fluid is known as subretinal

• Tractional RD —relieve traction by vitreoretinal surgery.

fluid or SRF).

• Once the retina has been separated from its main blood supply,

the photoreceptors slowly begin to degenerate, becoming non-

functional by 6 weeks.

• It is therefore essential that once an RD has been diagnosed,

that it is surgically reattached as soon as possible in order to regain

KEY POINTS

vision.

• PVD results in floaters and there may be a retinal tear.

• If the macula is detached (off) surgery is urgent.

• Subretinal fluid gets under the retina through a tear and lifts the sensory

retina off the retinal pigment epithelium, causing a detachment.

Aetiology

• Some RDs do not have tears but are exudative, tractional or solid in origin.

• A full thickness tear in the retina, which may result from a spon-

taneous PVD or may occur as a result of trauma, allows liquid vit-

Retinal detachment 85

40 Retinal and choroidal anatomy and imaging

Knowledge of retinal anatomy and physiology is vital to interpret retinal images

Anatomy

Choroid: fenestrated capillary-rich layer which supplies oxygen and micronutrients

to the retinal pigment epithelium and the outer third of the neurosensory retina.

The capillary layer is the choriocapillaris

Retinal pigment epithelium (RPE): monolayer of pigmented cells between the

Fovea

neurosensory retina and Bruch’s membrane. Tight junctions exclude large

Foveola

molecules and form the outer part of the blood retinal barrier

Inner limiting

Bruch’s membrane: an acellular layer between the choroid and RPE, which does

membrane

not form a significant part of the blood retinal barrier

Retinal vessels

Ganglion cell layer

Neurosensory retina: includes photoreceptors, ganglion cells and their axons

Retina

Layer of intermediary

(nerve fibre layer), other neurons (e.g. bipolar cells) and glial cells (e.g. Müller cells)

neurons

Retinal arteries, capillaries and veins: non-fenestrated vessels forming the inner

Photoreceptor layer

blood retinal barrier

Foveal avascular zone: approximately 0.045 mm zone in which retinal capillaries

Cones only

Cones, some rods

are absent

Rods and cones

Retinal pigment

epithelium

Human methylmethacrylate vascular cast

Choroid

Bruch's membrane

Inner choriocapillaris surface -

Cross section of choroid showing

Sclera

Choriocapillaris

large surface area for nutrient

flattened choriocapillary sheet and

exchange to the outer retina

outer larger choroidal blood vessels

Fluorescein photography filters

Exciter filter

Barrier filter

Retinal pigment

490 mm

515 mm

epithelium cells

Bruch's membrane

Flat

Choriocapillaris

sheet

Intermediate-sized

chorio-

choroidal vessels

Outer larger

capillaris

choroidal vessels

Absorption

Emission

spectrum

Topography of the posterior pole and retina

area centralis

Posterior pole

d = 5-6 mm

400

500

600

Wavelength (nm)

fovea

Indiocyanine green photography filters

Optic disc

Macula

Exciter filter

Barrier filter

d = 1.5mm

d = 1.5 mm

795 mm

830 mm

foveola

• Posterior pole area centralis (5-6 mm)

Fovea

• Macula fovea (1.5 mm)

d = 0.35 mm

• Fovea foveola (350 µm)

Fluorescein

Retinopathy pre-laser treatment

angiogram in a

Normal left macula in same eye

Disc

diabetic

new

Absorption

Emission

seen with i) fluorescein and

showing leaking

vessels

spectrum

ii) indocyanine green

'new vessels

elsewhere'

FAZ

700

800

900

i) Retinal vessels imaged with

Wavelength (nm)

fluorescein angiogram showing

Fundus fluorescein angiogram of a

loss of capillary network at

left eye with gross myopia and

foveal avascular zone (FAZ)

consequent

chorioretinal

degeneration

ii) Choroidal vessels imaged.

and atrophy

Indocyanine green angiogram

(ICGA) showing rich choroidal

blood supply at macula

86 Sub-specialty —Vitreoretinal and medical retina

Aims

red or brown pigments (e.g. melanin in RPE cells or subretinal

1 Know the anatomy of the choroid and retina.

blood). ICGA is useful in investigating choroidal disease, e.g.

2 Identify the main priorities of medical retinal disease.

choroidal neovascularization and choroidal tumours.

3 Methods of retinal imaging and appropriate use of a particular

imaging system.

Confocal scanning laser ophthalmoscope (SLO)

4 Understand the need for more than one modality of imaging.

A fundus camera using a low-power scanning laser for illumination

at different focal planes in the retina to produce tomographic images.

Medical retinal disease priorities

Diabetic retinopathy and age-related macular degeneration are

Optical coherence tomography (OCT)

the main priorities in medical retina in terms of socioeconomic

Non-invasive diagnostic imaging analogous to an ultrasound B

health care burden (see Chapter 3) but vascular occlusions occur

scan except that light and not sound is used; a higher resolution is

commonly with age particularly in association with systemic

therefore obtainable.A highly coherent light source is used to scan

disease. The inherited retinal dystrophies affect 1 in 4000 of the

the retina and produces high-resolution, cross-sectional and 3D

population —young and old. The management of medical retinal

images. Used for assessing retinal thickness, retinal oedema and

disease has been revolutionized as a result of developments in

optic nerve head imaging in glaucoma.

retinal imaging, the advent of molecular genetics and new treat-

ment modalities.

Terms used when describing fluorescein angiograms

Retinal imaging modalities, together with psychophysical and

Hyperfluorescence: Increased fluorescence relative to other struc-

electrophysiological evaluation, are very valuable in diagnosing

tures seen as black on white if negative film is used and white on

disorders of the retina, retinal pigment epithelium (RPE) and

black with digital photography.

choroid.

Hypofluorescence:Reduced fluorescence relative to other structures,

e.g. due to blocked fluorescence or decreased vascular perfusion.

Imaging

Window defect: Increased choroidal fluorescence seen through a

A fundus camera can be used to document baseline retinal find-

window of attenuated RPE, e.g. geographic atrophy or laser scars.

ings, track disease progression, screening

(e.g. for diabetic

Blocked fluorescence: Masking of fluorescence by opacity anter-

retinopathy) and clinical studies.

ior to it, e.g. subretinal haemorrhage.

• A fundus camera ensures high resolution, high quality images.

Fluorescein leakage: Characteristic of conditions in which the

• Colour fundus photography, fluorescein and indocyanine

outer (RPE) or inner (retinal vasculature) blood-retinal barrier is

green angiography are used to image the retina and surrounding

disrupted.

structures.

Autofluorescence: Fluorescence occurring without the injection

• Digital images allow rapid diagnosis and review, and are elec-

of fluorescein dye.

tronically transferred; they are useful for telemedicine.

Side effects of fluorescein and indocyanine green

Dyes used in imaging

Fluorescein

Indocyanine green (ICG)

Fluorescein. Sodium fluorescein is an orange dye that is excited by a blue

light to emit a yellow-green light. It is a small molecule, only 80% bound to

Contraindications

blood proteins, which diffuses freely through the choriocapillaris, Bruch’s

Absolute

Fluorescein allergy ICG, iodine or shellfish

History of severe

allergy

membrane, optic nerve and sclera.

allergies

History of severe

Indocyanine green (ICG). This is a green dye, which when excited by a near

Relative

Asthma

allergies

infrared light emits a near infrared light. It is almost 100% protein bound so it

Ischaemic heart

Asthma

only leaks slowly through the fenestrated capillaries of the choriocapillaris.

disease

Ischaemic heart disease

Previous allergic

Previous allergic reaction

reaction

Liver failure

Renal failure (use

Fundus fluorescein angiogram (FFA)

lower dose)

This is a sequence of fundus images taken immediately after so-

Adverse effects

Skin discolouration Mild to moderate 0.35%

dium fluorescein dye is injected into a peripheral vein. The fundus

Nausea 3-5%

(e.g. hypotension)

is illuminated by a blue light causing the fluorescein molecules to

Allergy 0.5-1%

Severe 0.05% (e.g.

fluoresce in the yellow-green spectrum. Barrier filters block re-

anaphylaxis)

flected blue light so that only yellow-green (i.e. fluorescent) light is

Excretion

Liver and kidneys

Liver

transmitted to the film or digital camera.A detailed 3D view of the

retina and of the level of fluorescence can be achieved by using a

stereoscopic viewing device or computer software. Good for view-

ing retinal detail.

KEY POINTS

• Fluorescein angiography provides fine detail of the retinal structures and

Indocyanine green angiography (ICGA)

vessels.

Near infrared fluorescence is recorded with infrared film or more

• Indocyanine green provides information about the choroidal vessels.

commonly with a digital camera, after the injection of ICG into a

• There are potential side effects or complications of these dyes.

peripheral vein. Light of this wavelength has better penetration of

Retinal and choroidal anatomy and imaging 87

41 Inherited retinal dystrophies and age-related macular degeneration

Microanatomy

Classification of age related macular degeneration (AMD)

ARM

Photoreceptors: Rods: for vision in dim light (shades of black

and white) and motion vision. Cones: for vision in bright light

Histopathology and colour fundus picture of soft confluent Drusen at macula

(high resolution and colour). Rods predominate outside the

Courtesy of Victor Chong

fovea, cones are most dense at the fovea. Retinal Pigment

Epithelium (RPE): Single layer of cells with an important role

in the turnover and support of photoreceptor outer-segments

and formation of photosensitive pigments. Forms the blood-

retinal barrier. Bruch’s Membrane: Separates the RPE from

choriocapillaris. See Chapter 40

Definitions

Soft Drusen

Dystrophy: Inherited disorder

AMD

Photophobia: Painful sensation in bright light

Nyctalopia: Poor or lack of vision in the dark

Choroidal neovascularization (CNV)

Geographic atrophy (GA)

Neurosensory

Phenotype: Clinical characterization including symptoms

retina

(e.g. photophobia, nyctalopia), fundus appearance and

Exudate

functional assessment

Oedema

Inherited retinal dystrophies

Haemorrhage

A. Peripheral dystrophies - affect peripheral vision and vision

CNV

in low light levels, e.g. retinitis pigmentosa, choroideraemia

RPE

= 80% AMD

and Leber's congenital amaurosis

Bruch's

See Chapter 19

membrane

Retinitis pigmentosa (RP) varies in severity, mode of

Choroid

inheritance, age at onset, progression and phenotype.

Inheritance patterns include: autosomal dominant (AD),

autosomal recessive (AR), X-linked (Xl). Mitochondrial and

Classic CNV

Occult CNV

Pigment epithelium

syndromic retinopathy are also described

detachment (PED)

B. Central dystrophies - affect the macular region. Early

onset central visual difficulties with photophobia, loss of

detailed vision and colour vision defects, e.g. cone

dystrophies, macular dystrophies including Best disease,

Stargardt/fundus flavimaculatus, Sorsby, Bull’s eye,

Dominant drusen (Doyne honeycombe) dystrophy

PED

C. Mixed dystropies - Cone-rods affected with loss of

central and peripheral vision

Urgent referral for consideration: laser or surgery

D. Syndromal - e.g. AR Usher syndrome with hearing loss

and RP

Laser depends on position,

Photodynamic therapy depends

Peripheral dystrophy: Retinitis

character and size

on level of vision, position,

pigmentosa with intra retinal

character and size

mid peripheral bone spicule

pigmentation

Treatments under evaluation

• TTT: Trans-pupillary thermotherapy

• Surgery:

• Submacular surgery

• Macular translocation, RPE transplantation

Disciform scar

• Anti-angiogenesis: steroids, modulation

See Chapter 19

of vascular endothelial growth factor

Rehabilitation: Registration, low visual aids, advice re second eye - to report

distortion/decrease in vision

Educate AMD patient to report if decrease or distortion in vision. Consider

Central dystrophy:

Mixed dystrophy:

vitamin supplementation: Age Related Eye Disease Study recommendations.

Best dystrophy

cone rod

See Amsler chart, Chapter 7

88 Sub-specialty —Vitreoretinal and medical retina

Aims

• Pigment epithelial detachment

(PED): Accumulation of

1 Types of inherited retinal degeneration.

oedema ± blood beneath the RPE. An underlying CNV is com-

2 Know the significance of early central visual symptoms and

monly present in older patients.

prompt referral for possible early treatment of neovascular age-

• Retinal oedema and exudate: Leakage of serum into and behind

related macular degeneration (AMD).

the retina from CNV. Lipid components not easily removed by

3 Treatment options and importance of low-vision aids and social

macrophages accumulate, often at the edge of the oedema, as

support in both inherited retinal degeneration and AMD.

characteristic yellowish lesions.

Skills to obtain

Pathology

Use the ophthalmoscope to learn to recognize retinitis pigmen-

• RPE. Accumulation of photoreceptor, outer-segment waste

tosa and AMD.

products and vesicular granular material. GA may be due to re-

duced metabolic exchange between the choroid and RPE.

Inherited retinal dystrophies

• Bruch’s membrane. Focal and diffuse thickening with age.

A large number of disorders with progressive retinal degeneration

Accumulation of Drusen and presumed degrade collagen ma-

which are variable in severity, age of onset and may have distin-

terial from the RPE.

guishing phenotypic and functional features.The term retinitis pig-

• Choroid. Neovascularization arises from the capillary layer of

mentosa is used to describe peripheral dystrophies, but the latter

choroid. Photoreceptor atrophy and scarring begins early in neo-

term covers a spectrum of inherited progressive retinal degenera-

vascularization, even without haemorrhage.

tions. Features include night blindness, progressive visual field loss,

reduced or non-recordable electroretinograms and characteristic

Risk factors for AMD

pigmentary retinal degenerative changes in 1 in 4000.

• Genetic and environmental are implicated.

Classification of these disorders is enhanced by knowledge

• Cigarette smoking is a known risk factor.

of the inheritance pattern, causative gene(s) and mutation(s) if

• Vascular disease, hypertension and light exposure are asso-

known, and more sophisticated phenotypic characterization in-

ciated with AMD but are not risk factors.

cluding psychophysics and electrophysiology.

• Supplementation with extra carotenoids, certain vitamins and

antioxidants may be associated with a decreased risk of develop-

Age-related macular degeneration

ing AMD in certain types of ARM/AMD.

• Commonest cause of blindness in the elderly population.

• Approximately 2% of over 65 year olds are registered blind in

Diagnosis and assessment

one or both eyes from AMD in the UK.

• Recent symptoms of central distortion/blurring raise the pos-

• Geographic atrophy accounts for approximately 80%.

sibility of neovascular AMD.

• Treatment options are limited and are mainly targeted at neo-

• An Amsler chart (p. 20) is useful in evaluating central vision.

vascular AMD using laser photocoagulation or photodynamic

• Gradual decline, however, suggests GA.

therapy. Anti-angiogenesis therapies are being evaluated.

• Dilated fundus examination and FFA is essential in order to iden-

• Early symptoms require prompt referral for evaluation and

tify treatable CNV.

possible treatment of choroidal neovascularization (CNV). See

Treatment

Chapter 7, Amsler chart.

• Various types of laser, including photodynamic therapy for neo-

Definitions

vascular AMD.

• Age-related maculopathy (ARM): Disorder of the macular

• 90% of AMD is untreatable. GA or neovascular AMD with

area most often occurring after 50 years of age, characterized by

occult subfoveal CNV often results in significant scarring and/or

Drusen ± changes in the retinal pigment epithelium (RPE).

haemorrhage. New therapies are undergoing evaluation.

• Age-related macular degeneration (AMD): Late stages of

Rehabilitation

ARM that lead to progressive central vision loss. Includes: geo-

Blind/partially sighted registration

graphic atrophy of the RPE and subsequently photoreceptor cell

• Financial allowance.

loss, CNV, pigment epithelial detachment, haemorrhages, exu-

• Talking books/clocks.

dates and scar tissue.

• Home visit by low-vision therapist to assess disability.

• Drusen: Yellowish deposits external to the neuroretina and

• Initiate community care, Social and/or voluntary services.

RPE. May be well defined and small (hard) or ill defined (soft).

• Contact with self-help groups.

Drusen may be discrete or confluent and are hallmarks of age-

related change found at the level of Bruch’s membrane.

Low-vision aids (see Chapter 9)

• Geographic atrophy (GA): Demarcated zones of apparent

• Optical aids: magnifiers, telescopes.

RPE atrophy.Associated with Drusen. Gradual central vision loss.

• Non-optical aids: lighting, large print books/bank statements.

• Choroidal neovascularization (CNV): Abnormal new blood

• Electronic aids: closed circuit television (CCTV).

vessels that arise from the choroid and proliferate with subse-

quent fibrous tissue. Often not identifiable on ophthalmoscopy

but may be visualized using FFA.

KEY POINTS

• Disciform scar: Subretinal fibrovascular scar. Usually part of the

• Inherited retinal degenerations common, but no therapy available.

healing response following CNV. Permanent vision loss occurs as

• AMD is the leading cause of blindness in industrialized countries.

the outer retina (including photoreceptors) becomes atrophic or

• Sudden-onset central distortion/blurring may represent treatable CNV.

replaced by fibrous scar tissue.

Inherited retinal dystrophies and age-related macular degeneration 89

42 Diabetic retinopathy classification and typical lesions

Cotton wool spot (CWS)

Non-proliferative diabetic retinopathy (DR)

Severe non-proliferative DR

Intraretinal

Microaneurysms

microvascular

abnormalities

Looping

White vessel

Needs referral to ophthalmologist to decide treatment

Does not need treatment

Proliferative DR

Mixed diabetic maculopathy (DM)

Clinically significant macular

oedema (CSMO)

and ischaemic maculopathy

Hard exudate

New vessels on disc

(NVD)

Haemorrhages

Cotton wool spot

Advanced diabetic eye disease

Needs laser

Traction band

Beading

Tractional and fibrotic

changes with laser scars.

New vessels elsewhere

This is end-stage disease.

(NVE) with fibrovascular

Vitreo-retinal surgery

changes

may help

Needs laser

All figures copyright S Downes

Classification

Non-proliferative

Severe non-proliferative

Proliferative DR

Advanced proliferative

Maculopathy (especially

(background) DR

(preproliferative) DR

late-onset diabetes)

Microaneurysms

Multiple haemorrhages

NV at disc (NVD) or

Vitreous haemorrhage

Focal or diffuse retinal oedema

Retinal haemorrhages

in all four quadrants

elsewhere (NVE)

Tractional retinal

near fovea

Cotton wool spots

Venous beading

Traction on NV causes

detachment

Focal oedema with ring of

Exudates outside

Intraretinal new vessels

vitreous haemorrhage

Neovascular glaucoma

exudates ('circinate') near fovea

temporal arcades

(NV)

or retinal detachment

Exudates near fovea

Haemorrhages near fovea

Loss of capillaries at macula

Sight-threatening — REFER TO OPHTHALMOLOGIST

(macula ischaemia)

Pathology

Basement membrane thickening

Acellular capillaries

'Angiogenesis' with

(Early) non-proliferative DR

Loss of endothelial cells and

'Capillary closure'

formation of NV

(Later) proliferative DR

pericytes

Local areas of retinal

Alteration of vascular

(Early, especially in late-onset DM)

Loss of vascular tone regulation

ischaemia and hypoxia

permeability

Maculopathy

Altered cellular adhesion

'VEGF response' and

Macular oedema

molecules

intracellular activation

Macular ischaemia

(including protein kinase C)

Sub-specialty —Vitreoretinal and medical retina

Aims

neovascularization (whose growth is induced by the release of

1 Learn the classification of diabetic retinopathy (DR) and its

angiogenic cytokines from the ischaemic retina).

pathogenesis.

• If new vessels grow at the optic disc they are referred to as

2 Be aware of contributory risk factors to severity of retinopathy

NVD.

(e.g. duration of diabetes, pregnancy, blood pressure).

• If new vessels grow at any other location they are described as

3 Understand the importance of DR screening.

new vessels elsewhere (NVE).

The new vessels are a response to hypoxia and ischaemia in an

• DR is the major cause of poor vision in the working population

attempt to increase the oxygen supply to the retina. However,

in the UK, Ireland, USA, Australia and the Indian subcontinent.

these vessels are weak and friable and bleed easily casing vitreous

The annual incidence of blindness from DR varies between 0.02%

haemorrhage.They may also cause traction on the retina resulting

and 1%.

in tractional retinal detachment.

• Alterations in different biochemical pathways as a result of

diabetes have been implicated in the development of the micro-

Microvascular changes resulting in leaking vessels

vasculature abnormalities that are seen in DR.

• Endothelial cell loss, pericyte loss of vascular tone result in in-

• An international standard classification of DR is essential for

creased permeability of the retinal vessels and hence exudation of

guidelines in screening, treatment protocols and research.

blood and blood products into the retina.

• Blot and dot haemorrhages, hard exudates and diffuse oedema

Definitions

are seen.

Microaneurysms: Outpouching of retinal capillaries. May bleed,

• These changes can also lead to localized vessel wall weakness

leak or become occluded.

and microaneurysm formation. These microaneurysms leak and

Cotton wool spot: Microinfarct of the retinal nerve fibre layer

exudates form in a circle around the aneurysm —‘circinate

(NFL) causing a localized swelling of the NFL axon (non-specific

exudates’.

indicator of retinal ischaemia).

Retinal oedema and exudate: Leakage of serum into the neural

Screening

retina due to vessel wall damage. Lipid components that are not

• DR is the leading cause of blindness in the working population

easily removed by macrophages accumulate, often at the edge of

in the UK.

the oedema, as characteristic yellowish lesions.

• Twenty-five per cent of diabetics develop DR; 10-13% of dia-

Venous beading: Venous irregularities, ‘sausaging’ and engorge-

betics have sight-threatening DR.

ment. Sign of retinal ischaemia and powerful predictor of conver-

• Prevalence of DR increases with duration of diabetes.

sion to proliferative retinopathy.

• Natural history of DR is known.

Retinal neovascularization/new vessels: Fragile new vessels grow

• Early treatment is effective in preventing visual impairment.

outside the retina along the posterior surface of the vitreous.

• An effective screening service requires effective recall of eligi-

Changes in bloodflow or traction on the new vessels, including

ble patients, 80% sensitivity, 95% specificity and quality assurance.

posterior vitreous detachment, may cause them to haemorrhage

• Digital photographic screening is the preferred method.

into the vitreous cavity (vitreous haemorrhage).

• Detection of any DR should direct attention towards improving

blood pressure and glycaemic control.

Pathology

Microvasculature changes causing ischaemia

KEY POINTS

• Basement membrane thickening, endothelial cell damage and

• DR is the leading cause of blindness in the working population of the devel-

loss, and increased platelet adhesiveness lead to narrowing of the

oped world.

retinal vessels and hence ischaemia.

• Screening and early treatment can prevent vision loss.

Ischaemia is manifest as: cotton wool spots, deep retinal

• Uncontrolled hypertension makes DR worse.

haemorrhages, venous beading and new vessel formation/

Diabetic retinopathy classification and typical lesions 91

43 Diabetic retinopathy treatment

Treatment options

Blood pressure, lipid and

Panretinal photocoagulation

Macular laser

Vitrectomy

glycaemic control

(PRP) laser

Reduce progression and severity

Laser (usually argon)

Focal or grid pattern

Aims: to

of diabetic retinopathy (DR)

Indicated for proliferative DR to

Encourages absorption of

Clear vitreous haemorrhage

Reduce need for laser

reduce risk of vision loss due to

oedema

Allow further PRP laser

vitreous haemorrhage or

Relieve retinal traction and repair

tractional retinal detachment

retinal detachment

Treat diffuse macula oedema due

to vitreous traction

In the UK and Ireland, the National Framework for Diabetes aims to raise

the standards for diabetic care including DR, and reduce blindness from DR

Proliferative diabetic retinopathy (DR)

Clinically significant macular oedema (CSMO)

Panretinal

Laser scar

photocoagulation

Parafovea with exudate

New vessels

Microaneurysms

on disc (NVD)

Needs more laser

Treated CSMO

Multiple episodes

Macula now dry

Microaneurysms

Panretinal

photocoagulation

Exudate

New vessels

elsewhere (NVE) -

Coalescing laser scars

still proliferative

and undergoing

more laser

Needs more laser

Needs gentle laser burns

DR treatment options

Good diabetic, blood pressure and lipid control.

Antiangiogenesis agents under evaluation.

Current therapies include (a) laser and

(b) vitrectomy surgery

(a)

(b)

All figures copyright S Downes

92 Sub-specialty —Vitreoretinal and medical retina

Aims

• Once adequate laser has been applied, the abnormal vessels will

1 Be aware of the treatment options in diabetic retinopathy

regress in about 8 weeks.

(DR).

2 Be able to explain about laser treatment to the patient.

Macular laser

• Focal laser is used to destroy microaneurysms that are leaking

• Blood pressure, lipid and glycaemic control:

exudate into the macular area. After the aneurysm has been

—reduces the progression and severity of DR;

treated the exudates will resorb.

—reduces the need for laser treatment.

• Grid laser is used to treat non-ischaemic diffuse macular

• Patients should also be advised not to smoke as this contributes

oedema. The entire macula, excluding the fovea, is treated with

to vascular damage.

very tiny low-powered laser in order to encourage absorption of

• Any underlying anaemia should be treated.

oedema.

• Patients must be warned that macular laser treatment is used to

prevent vision getting worse, and does not always improve visual

TIP

acuity. Some patients notice a scotoma after macular laser

Early treatment = better vision.

treatment.

Vitrectomy

This is a specialized procedure whereby the vitreous is removed

Treatment options

via a trans-pars plana incision, hence the term trans-pars plana vit-

The commonest treatment for DR is laser photocoagulation —

rectomy (TPPV). TPPV is carried out by a vitreoretinal surgeon,

either panretinal, or focal laser or grid laser to the macula. DR

usually under general anaesthesia.

often requires multiple treatments.

Indications

Panretinal photocoagulation (PRP)

• To clear vitreous haemorrhage —this allows the surgeon to visu-

• Indicated for proliferative DR to reduce the risk of vision loss

alize the retina and apply further PRP laser.

due to vitreous haemorrhage or tractional retinal detachment.

• To relieve retinal traction and repair retinal detachment.

• An argon laser is used to produce 1500-3000 tiny burns in the

• To treat diffuse macula oedema due to vitreous traction.

peripheral retina, sparing the macula, papillomacular bundle and

optic nerve head.This causes regression of new vessels at the optic

disc (NVD) and new vessels elsewhere (NVE).

• The patient will have reduced peripheral and night vision post

PRP.

KEY POINTS

• PRP is performed in the out-patient clinic using a laser attached

• Tight blood pressure, lipid and glycaemic control reduces the progression

to a slit lamp. The treatment requires topical anaesthesia as a spe-

and severity of DR and the need for laser treatment.

cial contact lens is used to apply the laser burns.

• PRP is the treatment for proliferative DR.

• Depending on the patient’s ability to tolerate the treatment and

• Focal laser is used to treat leaking microaneurysms at the macula, that are

the amount of burns required, the laser is applied over a number

threatening vision.

of sessions.

Diabetic retinopathy treatment 93

44 Retinal vein occlusion

The central retinal vein drains all the layers of the retina

Anatomy

Central retinal vein (CRV) course at optic nerve head

and the optic nerve head anterior to the lamina cribosa.

When it is occluded, there is marked venous engorgement

Layers

and leakage with retinal oedema, ischaemia and haemorrhage

Retina

Nerve fibre layer

Choroid

Prelaminar

Sclera

Laminar

Central

Human methylmethacrylate vascular cast

retinal

vein

Retrolaminar

All tissue has been dissolved away from the intralumen vascular casts

The optic disc: retinal venule

Isolated retinal cast

tributaries forming the central

with central retinal

retinal vein deep in the optic cup

artery and vein

Central

Retinal vasculature

retinal artery

Optic

cup

Retinal vein

tributaries

Neural

Central retinal vein

rim

Central retinal artery

Central retinal vein occlusion (CRVO) (left eye)

Neovascular glaucoma - iris new vessels and pathology

Histopathology of iris

surface with arrows

showing iris

neovascularization

Acknowledgements to Dr Brendon McDonald,

Neuropathologist, Oxford Radcliffe Infirmary,

Oxford for the histopathology slide

Rubeosis iridis: (iris neovascularization)

- end-stage disease

Hypertensive retinopathy

Branch retinal vein occlusion (BRVO)

• Usually asymptomatic and bilateral

• Can have BRVO or CRVO

• Range of features from generalized retinal

arteriolar narrowing, cotton wool spots, exudates,

arteriovenous crossing changes, flame-shaped

haemorrhages, to optic nerve head swelling

Fluorescein angiogram

Affecting three quadrants

Affecting one quadrant

of branch vein occlusion

(left eye)

(right eye)

Medical associations with retinal vein occlusion

Systemic

Retinal flame

BRVO and silver wiring

• ↑ Blood pressure

• Hyperviscosity syndromes

haemorrhages

• Diabetes mellitus

• Hypercoaguable disorders

• Hyperlipidaemia

94 Sub-specialty —Vitreoretinal and medical retina

Aims

Non-ischaemic CRVO

1 Identify the clinical features of central and branch retinal vein

• Mild fundus changes.

occlusion (CRVO and BRVO).

• No afferent papillary defect.

2 Management of CRVO.

• Visual loss not as profound as in ischaemic CRVO.

3 Management of BRVO.

• May not require laser treatment.

Skills to obtain

Branch retinal vein occlusion

Identify retinal vein occlusion with an ophthalmoscope.

Occur at arterovenous crossings and are 3 times more common

than CRVOs.

Retinal vein occlusion

Presents as with CRVO if extensive, or incidental finding. Reti-

Common cause of painless loss of vision—the condition can occur

nal haemorrhages and cotton wool spots are confined to one area.

at any age, with 85% of patients aged >50 years. Classified into

Chronic retinal changes: exudate, macular oedema and collateral

central (CRVO) and branch (BRVO), depending on the site of the

vessels. New vessels arise from the retina rather than the iris,

obstruction.The vein is occluded with thrombus, which represents

therefore these patients may get a vitreous haemorrhage but not

a secondary event following:

neovascular glaucoma.

• changes to the vascular endothelium;

• external pressure from an overlying arteriole that shares a

Management

common adventitial sheath (BRVO);

In both CRVO and BRVO it is important to detect and treat any

• increased thrombotic tendency.

underlying systemic disease in order to prevent the recurrence of

the venous occlusion.

Pathology

• Ophthalmic management:

Exact aetiology is unknown.The resulting venous occlusion causes:

—Check intraocular pressure (IOP) as may cause CRVO.

• Increased intravascular pressure:

—Screen for presence of new vessels (over 2 years).

—intraretinal haemorrhage;

• Medical management:

—retinal oedema;

—Check FBC, ESR, U&E, lipid profile, blood sugar, plasma

—altered vascular permeability.

proteins and blood pressure.

• Stagnation of flow:

—Medical treatment of cardiovascular risk factors.

—capillary non-perfusion;

—Aspirin.

—retinal ischaemia leading to the growth to new vessels at the

optic disc, retina or iris.

Treatment

Visual prognosis depends on the type of occlusion, the severity

CRVO

of the initial insult and the ocular sequelae. Visual loss is worse in

• Look for iris neovascularization in ischaemic CRVO—typically

CRVO than BRVO. Some small BRVO are asymptomatic, espe-

occurs at 3 months (‘100 day glaucoma’).

cially if it affects only one quadrant nasal to the disc (i.e. away from

• Reduce IOP if over 22 mmHg.

the macula) —only a slightly enlarged blind spot is found.

• Laser PRP is applied in the presence of new vessels.

Visual loss may follow:

• Cyclodiode if advanced and glaucoma.

• Ischaemic—vein occlusion affecting the fovea. New vessels give

BRVO

rise to vitreous haemorrhage or neovascular glaucoma.

• Follow up BRVO every 4-6 weeks for 6 months. If it worsens

• Exudation—blood-retinal barrier breakdown causes macular

and looks ischaemic, use PRP.

oedema and retinal exudate.

Central retinal vein occlusion

Hypertension and the eye

The CRV deep in the optic cup is occluded, affecting drainage

Looking at the retina you are looking at blood vessels in the body,

from all four retinal quadrants, resulting in usually unilateral pain-

which gives some idea of vascular damage. Severe vascular

less visual loss.

damage in the general population is uncommon and is seen in

special groups, for instance patients with renal failure.

Signs

• Afferent pupillary defect common.

• Dilated retinal examination demonstrates:

Systemic hypertension

Accelerated hypertension (rare!)

—retinal haemorrhages in all four quadrants;

Early changes:

Marked systemic changes plus lots

—optic disc swelling;

silver wiring

of retinal flame haemorrhages,

—venous dilation and tortuosity ±cotton wool spots.

AV nipping

star exudates at macula,

Later changes:

papilloedama, BRVO or CRVO

Ischaemic CRVO

flame haemorrhages

Up to 33% of cases are ischaemic, associated with new vessel

papilloedema

formation on the iris (rubeosis iridis) or disc, a risk of neovascular

glaucoma, and vitreous haemorrhage, and blindness. Requires

laser treatment.

KEY POINTS

Signs:

• The CRV drains the entire retina and prelaminar optic nerve head.

• Deep retinal haemorrhages.

• Ischaemic-type CRVO may develop neovascular glaucoma.

• More than 10 cotton wool spots.

• Some BRVOs are asymptomatic, but indicate systemic disease.

• Large areas of capillary non-perfusion (detected with FFA).

Retinal vein occlusion 95

Aims

Diagnosis and management

1 Understand the vascular anatomy of the retina and optic nerve

Symptoms

head.

• Painless loss of vision (NB, non-ocular pain may occur such as

2 Identify the clinical features of a central retinal artery occlusion

temporal or scalp tenderness in giant cell arteritis (GCA)).

(CRAO).

• Profound drop in visual acuity

(unless cilioretinal artery

3 Be able to manage a patient with CRAO.

sparing).

• Afferent papillary defect.

Anatomy

The eye has a rich blood supply from the ophthalmic artery via the

Signs

central retinal artery (CRA) and the posterior ciliary arteries

Perform a dilated fundal examination to detect:

(PCAs). The CRA supplies the superficial nerve fibre layer and

• Cherry red spot at macula.

inner two-thirds of the retina. The PCAs supply the rest of the

• Embolus occasionally visible at optic disc.

anterior optic nerve and uvea (iris, ciliary body and choroid), and

• Attenuation of arterioles.

hence the deep retinal layers.The anatomy is known from vascular

• Retinal pallor.

casts (in vitro) and fluorescein angiography.

• Mild disc swelling.

In vascular casts of the eye the cadaver ophthalmic artery has

been injected with a plastic and the tissue has been dissolved away

Treatment

leaving only the vessel lumen —the cast.

The aim is to re-establish circulation within the CRA. This is at-

The CRA is an end artery of the ophthalmic artery, which sup-

tempted by:

plies the inner two-thirds of the retina. The choriocapillaris sup-

• Lowering the intraocular pressure (IOP) using:

plies the outer retina.

—acetazolamide 500 mg i.v.;

—ocular massage;

—anterior chamber paracentesis (1 ml aqueous withdrawn).

WARNING

• Vasodilation: rebreathe into a paper bag

(carbon dioxide

CRA obstruction causes ischaemia of the inner retinal layers resulting in

increases).

oedema of the nerve fibre layer (NFL).

• Start cholesterol lowering statins, e.g. Simvastatin,Atorvastatin.

Urgent: If bloodflow is not restored within 100 min, irreversible damage oc-

• Start antiplatelets, e.g. aspirin 300 mg stat then 75 mg daily or

curs at its narrowest point, which is the lamina cribrosa. A blockage more dis-

clopidogrel 75 mg daily, within 48 hrs.

tally gives rise to a branch artery occlusion.

WARNING

It is essential to check the erythrocyte sedimentation rate (ESR) and CRP to

Pathology

investigate for an inflammatory cause for CRAO, since GCA is often a bilateral

condition with catastrophic visual loss if not treated appropriately.

Retinal

Arterial occlusion

Inner retinal ischaemia

infarction gives

results from

causes

rise to

Outcome

Visual recovery is dependent on the interval between onset and

• Circulating

• Intracellular oedema —

• Loss of NFL

presentation. There has not been a clinical trial comparing treat-

embolus (e.g.

the retina appears white

• Pale optic disc

ment versus no treatment —but it is believed that 66% of patients

heart, carotids)

which masks the

have vision <6/60 following CRAO.

• Local atheroma

choroidal circulation,

• Arteritis (e.g.

except at the macula

giant cell arteritis)

‘cherry red spot’

Other investigations

• Miscellaneous

Examine for carotid bruits, heart murmurs and irregular pulse

(e.g. migraine,

(atrial fibrillation is a cause —needs anticoagulation). Arrange

syphilis, herpes

carotid Doppler studies, 24 h Holter monitor and echocardiogram.

zoster)

Follow-up by a physician.

Cilioretinal artery

KEY POINTS

NB, 15-20% of individuals have a supplementary arterial supply

• The CRA supplies the inner two-thirds of the retina.

to the macula via a cilioretinal artery derived from the posterior

• Do an ESR in all cases of CRAO to exclude GCA.

ciliary circulation at the disc. In the event of a CRAO, the macula

• A cilioretinal artery is present in 15-20% of individuals, which affords some

would remain perfused in these patients with some preservation

protection from severe visual loss.

of vision.

Retinal artery obstruction 97

46 HIV infection and AIDS

• AIDS (acquired immune deficiency syndrome) is caused by

Eyelids

infection with HIV (human immunodeficiency virus). It was

first described in 1981 in the USA and is now a global pandemic

• The number of reported cases underestimates the true extent

of this infection with over 75% of cases occurring in

sub-Saharan Africa, where the major mode of transmission

is heterosexual sex

• The incidence of heterosexual transmission is increasing in the

USA, Europe and Australia whereas intravenous drug users

(IVDU) and homosexual transmission is plateauing

• HIV infects cells by attachment to the CD4 antigen complex

found on many cells (CD4 cells, B-lymphocytes, macrophages,

Molluscum contagiosum on

Kaposi sarcoma lower eyelid

cells in CNS)

eyelid (usually multiple in HIV)

Intraocular inflammation

Retinal ischaemia

Herpes zoster ophthalmicus (5i) plus

maxillary branch involvement (5ii)

Anterior uveitis with

Cotton wool spots

granulomatous keratoprecipitates

Retinal/choroidal infections

Cytomegalovirus (CMV) papillitis and chorioretinitis

Varicella zoster virus retinitis (VZVR)

Toxoplasmosis retinochoroiditis

HIV modes of transmission

Sexual transmission (homosexual and heterosexual)

Parenteral transmission with blood and blood products:

semen from artificial insemination and organ transplantation

Occupational risk: small risk for healthcare workers of 0.3%

WARNING

after a single percutaneous exposure to HIV-infected blood.

Varicella zoster virus retinitis (VZVR) - may

Infection risk also from blood contamination of mucous

blind patients

membranes, non-intact skin and conjunctiva

Pneumocystis carinii pneumonia

• Acute retinal necrosis (ARN) and

Perinatal transmission: accounts for 80-90% of all

(PCP) choroiditis

progressive outer retinal necrosis (PORN)

paediatric HIV infections. Congenital HIV infection may occur

when immunocompetent and

transplacentally or intrapartum. The majority of infection

Visual prognosis:

immunosuppressed

occurs during birth or from breastfeeding

VZVR, CMV, toxoplasmosis

• PORN: bilateral multifocal retinitis with

retinochoroiditis and candida

Other routes: no evidence of HIV transmission from tears,

opacification in the outer retina and rapid

endophthalmitis may cause

sweat, urine or other body fluids

progression. Minimal or no vitritis. Very poor

severe visual loss.

NB. 30-50% of the non-HIV population will have serological

prognosis with standard therapies, leading

PCP and cryptococcal retinitis

evidence of previous toxoplasmosis

to blindness in most cases

is treatable

98 Sub-specialty —Vitreoretinal and medical retina

Aims

Toxoplasmosis retinochoroiditis (Toxoplasma gondii)

1 Modes of transmission of HIV (no evidence via tears).

• White or yellow patch of focal retinal necrosis. In HIV lesions

2 Lid, anterior segment, orbit, retinal and neuro-ophthalmic

tend to be larger; bilateral disease in 18-38%; unusual forms occur

manifestations.

(solitary, multifocal or miliary), often there is no pre-existing scar;

3 Causes of permanent visual loss in HIV.

minimal vitritis; prolonged therapy is required.

Ophthalmologic disorders in HIV

Syphilitic retinitis

Ophthalmic problems in AIDS are common and range from mild

Myriad presentations —vitritis, multifocal choroiditis, retinal vas-

conjunctivitis to sight-threatening retinitis. Any ocular or orbital

culitis, neuroretinitis, optic atrophy or oedema, exudative retinal

tissue may be involved. The commonest and most important op-

detachment, choroidal effusion, pigmentary retinopathy, and ve-

portunistic infection is cytomegalovirus retinitis (CMVR).

nous and arterial occlusions.

Lids/conjunctiva

Cryptococcal choroiditis (Cryptococcus neoformans)

• Trichomegaly —long eyelashes.

Variably-sized deep choroidal infiltrates; may be asymptomatic.

• Molluscum contagiosum on eyelids.

Pneumocystis carinii choroiditis

• HIV-related conjunctivitis.

Superficial yellow-white choroidal lesions.

• HIV conjunctival microvasculopathy —dilated, corkscrew-like,

tortuous vessels seen on slit lamp examination.

Mycobacterium tuberculosis choroiditis

• Kaposi’s sarcoma —flat or raised (if present >4/12) violaceous

Single large granuloma or multifocal; ±retinal vasculitis; frequent-

vascular lesion, surrounded by tortuous and dilated vessels. Com-

ly bilateral; choroidal neovascularization may develop at sites of

mon in conjunctival fornix. Treated by excision, chemotherapy or

healed spots.

radiotherapy.

Mycobacterium avium-intracellulare choroiditis

• Conjunctival granulomas due to cryptococcal infection, tuber-

Similar to multifocal choroiditis seen in cryptococcal and Pneu-

culosis and other mycotic infections.

mocystis carinii pneumonia (PCP) infection.

• Squamous cell carcinoma (see Chapter 24). Associated with

human papillomavirus infection. Aggressive tumour found on the

Candida endophthalmitis (Candida albicans)

lid or conjunctiva.

Small, whitish, multifocal, circumscribed chorioretinal infiltrates;

• Herpes zoster opthalmicus (HZO) often affects the VIIth nerve

retinal haems; dense vitritis and ‘fluff balls’ (vitreous abscesses)

too.

progress to endophthalmitis; often IVDU.

Cornea/anterior uveitis

Aspergillus endophthalmitis

• Anterior uveitis from drug toxicity (rifabutin, cidofovir).

Dense vitritis and vitreoretinal abscesses (similar to Candida

• Herpes simplex keratitis.

infection).

• HZO keratitis.

Ocular histoplasmosis infection (Histoplasma capsulatum)

• Microsporidia: a protozoal infection causing coarse, superficial,

punctate keratitis with minimal conjunctival reaction.

Endophthalmitis (iritis, vitritis, yellow iris infiltrates, multiple

creamy foci of retinochoroiditis + pulmonary or disseminated

Orbital disease

infection) or solitary chorioretinal granuloma (±vitritis).

• Periorbital B cell lymphoma.

• Aspergillus mass.

Primary intraocular B cell lymphoma

• Burkitt’s lymphoma.

Typically high grade; significant vitritis

± iritis; peripapillary

• Kaposi’s sarcoma.

infiltrates; disc swelling; yellow-white sub-RPE lesions; vascular

sheathing; and vein or artery occlusion.

Retinal disease

HIV retinopathy

Neuro-ophthalmic disorders in HIV

• Cotton wool spots.

• Optic disc swelling secondary to cryptococcal meningitis.

• Retinal haemorrhages.

• Papilloedema secondary to progressive multifocal leucoen-

• Microaneurysms.

cephalopathy (PML), cerebral infarction, intracranial toxoplas-

• Ischaemic maculopathy.

mosis or lymphoma.

• Immune recovery uveitis (IRU). Occurs in eye with quiescent

• Optic atrophy secondary to retinal disease.

CMVR in patients responding to HAART, defined as vitritis of

• Visual field defects secondary to space-occupying lesions.

≥1+ or trace of cells + epiretinal membrane or cystoid macular

• Cranial nerve palsies secondary to intracranial SOL or

oedema.

infection.

• Unilateral facial palsy may be secondary to aseptic meningitis.

Retinal infections

Cytomegalovirus retinitis (CMVR)

Haemorrhagic or non-haemorrhagic, frosted-branch angiitis or

mimic central retinal vein occlusion.

KEY POINTS

Epstein-Barr virus (EBV) retinitis

• No evidence that HIV is transmitted from tears.

Multifocal choroidal inflammation; typically prodromal malaise.

• HZO or multiple molluscum contagiosum in a young adult may indicate HIV.

EBV DNA is present in normal ocular tissue hence its presence in

• Increased orbital B cell lymphoma in HIV.

vitreous biopsy is not conclusive evidence of EBV uveitis.

HIV infection and AIDS 99

47 Pupil abnormalities

Pupil abnormalities

Sympathetic innervation of pupil

Midbrain

Edinger-Westphal

nucleus

Hypothalamus

Dilator

Periaqueductal

pupillae

gray

Aqueduct

Sphincter

Pons

pupillae

Pretectal

Long ciliary nerve

nuclei

Postganglionic neurone

Cervical

in carotid plexus

Posterior

Ach

cord

commissure

Superior cervical ganglion

Lateral

Preganglionic neurone

Ach

Ciliospinal

geniculate

centre of bulge

body

C8-T1

NA = Noradrenaline

Ach= Acetylcholine

Ciliary ganglion

Occulomotor

(3rd) nerve

Small

Horner's syndrome

pupil(s)

Uveitis

Drugs, i.e. pilocarpine

Neurosyphilis, i.e. Argyl Robertson

Long-standing Holmes-Adie pupil(s)

Sphincter pupillae

Congenital miosis or microcoria

Both pupils

Light to

constrict

Asymmetric

Physiological anisocoria

right pupil

pupils

(20% of population)

Physiological anisocoria (i.e. unequal pupil size)

Large

3rd nerve palsy

This can be distinguished from pathological anisocoria by observing

pupil(s)

Sphincter damage

the pupil size in the dark and then in the light — physiological

Drugs

anisocoria which is usually subtle should not change dramatically in

Dorsal midbrain syndrome

different levels of illumination (as opposed to Horner's syndrome which

Holmes-Adie pupil(s)

looks worse in the dark)

Posterior communicating

A relative afferent pupillary defect (RAPD) indicates serious ophthalmic

artery aneurysm

pathology (most commonly retinal or optic nerve disease) which

warrants immediate referral to an ophthalmologist

Holmes-Adie pupil

Congenital Horner's syndrome

3rd cranial

Pupillomotor

nerve

fibres are

superficial

Aims

• Size.

1 Understand how to assess a patient with abnormal pupils.

• Shape.

2 Understand the causes of pupil abnormalities.

• Light response.

3 Understand the neuroanatomy of pupillary light reflexes.

• Near response.

Pupil examination

Afferent pupil defect (APD) / relative afferent pupillary

When examining pupils you need to check for:

defect (RAPD)

• Symmetry.

• An APD results from damage to the visual pathway anywhere

100 Sub-specialty —Neuro-ophthalmology

from the retinal ganglion cell layer to the lateral geniculate body,

• Horner’s syndrome can be confirmed by putting 4% cocaine

thus causing a reduction in the input (afferent) signal reaching the

drops into each eye and observing the pupils 40 min later.The nor-

brainstem when a light is directed at the affected eye. Hence there

mal pupil will dilate, the Horner’s pupil will not.

is a similarly reduced output (efferent) signal reaching the pupil,

• Causes of Horner’s syndrome include Pancoast’s tumour of the

which consequently constricts to a lesser extent than if it had

lung, thoracic aortic aneurysm, trauma, carotid artery dissection

received a full signal.

(usually accompanied by neck pain) and CNS disease.All patients

• Because of the consensual light reflex, the unaffected pupil will

should be investigated appropriately.

also constrict to an equally lesser extent when the light is directed

• In congenital Horner’s syndrome the iris on the affected side is

towards the damaged side.

a different colour —iris heterochromia.

• Hence, if a light is directed at the better eye both pupils will con-

• Contamination of the eye with pilocarpine causes miosis.

strict fully and equally. If it is the immediately swung over (‘swing-

• Uveitis that has resulted in posterior synechiae can result in a

ing flash light test’) and directed at the affected eye (e.g. an eye

small pupil.

with an optic nerve lesion) both pupils will appear to dilate —

• Rarely, congenital microcoria can occur.

RAPD. In fact what has happened here is that both pupils are con-

stricting but to a lesser degree than when the light was directed at

Light-near dissociation

the normal eye, hence they only appear to dilate. When the light is

In some cases the pupil(s) will accommodate but not react to light.

swung back to the better eye the pupils will constrict.

This dissociation of the light and near reflex can occur in various

syndromes.

Fixed dilated pupil

• Dorsal midbrain or Parinaud’s syndrome. This may be due to a

• If a pupil is dilated and doesn’t react to light or accommodation,

lesion (e.g. pinealoma, cranipharyngioma) compressing the pupil-

it is important to examine eye movements and levator function in

lary light reflex fibres. The pupils may be large and eccentric.

order to exclude a third nerve palsy. NB, a unilateral enlarged

Associated features include absence of upgaze, upper lid retrac-

pupil caused by uncal herniation is a neurosurgical emergency.

tion and convergence retraction nystagmus, characterized by

• Because of the superficial location of the pupillomotor fibres

rapid convergence movements and retraction of both eyes on

(see figure), a partial third nerve palsy can occur where only the

attempted upgaze.

pupil is involved. In such cases a tumour or posterior communicat-

• Neurosyphilis or Argyll Robertson pupils. These pupils are

ing artery aneurysm must be excluded.

small and irregular, do not react to light but react briskly to near

• A fixed dilated pupil can result from inadvertent or accidental

stimuli.

contamination of the eye with cycloplegic agents such as atropine

• Holmes-Adie pupil. This is thought to result from a viral infec-

or cyclopentolate, hence the importance of a detailed history.

tion; the affected pupil is initially large and eventually may become

• Previous trauma or surgery where there has been extensive

miosed.There is no reaction to light, the near reflex is intact but de-

damage to the sphincter pupillae can result in a fixed dilated pupil.

layed and tonic (the patient should be asked to focus on a near tar-

• A fixed semidilated pupil in the presence of a hazy cornea, red

get for at least 1 min before the pupils begin to constrict, and when

eye and pain is seen in acute angle-closure glaucoma.

the patient is then asked to relax his accommodation the pupils are

slow to dilate again). These patients may also have absent tendon

Small pupil (miosis)

reflexes. Both pupils may eventually become involved.

• A small pupil in association with a very small amount of ptosis

• Patients with Myotonic dystrophy may have light-near

(no more than 2 mm —due to paralysis of Müller’s muscle) is

dissociation.

known as Horner’s syndrome. This results from a lesion of the

• Patients with diabetes may develop a pupil neuropathy result-

sympathetic chain anywhere from the hypothalmus to the eye.

ing in light-near dissociation.

• On dimming the lights the anisocoria will become more obvious

as the affected pupil doesn’t dilate in the dark as well as its

counterpart.

KEY POINTS

• There may be other associated features such as elevation of the

• Fixed dilated pupil —‘surgical third’ must be outruled.

lower lid, which together with the ptosis gives the appearance of

• Unilateral miosis —Horner’s syndrome must be outruled.

enophthalmos, reduced sweating on the ipsilateral side of the face

• RAPD —indicates optic nerve or retinal disease.

and occasionally conjunctival hyperaemia.

Pupil abnormalities 101

48 Optic nerve disease

Features of optic atrophy and papilloedema

Visual field loss

Reduced visual acuity

Reduced colour vision

Relative afferent

pupillary defect

Enlarged blind spot in papilloedema

N D

Centrocaecal scotoma in Lebers optic

Reduced

atrophy or vitamin B12 deficiency

visual

acuity

Red desaturation

Bitemporal hemianopia in optic

atrophy 2∞E pituitary tumour

Swollen discs

Multiple sclerosis (MS)

Pale

Left nerve is normal

Acute right papillitis

(swollen disc) in MS

Right unilateral optic

Left disc normal

optic neuritis

atrophy in MS

Demyelinating

plaque

Dawson's fingers

Benign intracranial hypertension (BIH)

Right optic

nerve higher

signal than

left

Coronal MRI scan showing

demyelination and high

Sagittal MRI scan showing

signal in right optic nerve

demyelination involving the

corpus callosum

Bilateral chronic papilloedema secondary to BIH

Leber’s Hereditary Optic Neuropathy (LHON)

A hereditary optic neuropathy affecting young males 20-30 years

Leber’s Hereditary Optic Neuropathy - bilateral involvement

Mitochondrial inheritance (i.e. passed via mitochondrial DNA) passed

through female side of the family in most cases

Often smokers

Presents with

Subacute painless loss of central vision in one or both eyes

Second eye involved within weeks-months

Centrocaecal scotoma

Typical circumpapillary telangiectatic microangiopathy

The primary mutation has prognostic implications:

11778 -

2-17% recovery

Blurred nasal disc margins and pre-capillary telangiectasis

3460 - 15-30% recovery

Typically discs swollen in the acute phase

14484 - 37-50% recovery

Treatment : none, advise to stop smoking

102 Sub-specialty —Neuro-ophthalmology

Aims

• Visual field defect: enlarged blind spot if there is significant

Know the causes of optic atrophy (pale disc) and swollen discs.

swelling; altitudinal defect if disc swelling is secondary to is-

chaemic optic neuropathy.

Optic atrophy/neuropathy

• Blurred disc margin ± splinter haemorrhages (see figure).

Clinical features

• VA is reduced, but can be normal, depending on the degree of

Aetiology

optic atrophy.

• Vascular: e.g. AION, CRV or diabetic papillopathy.

• In those patients with subtle optic atrophy and apparently nor-

• Inflammatory: ‘papillitis’, e.g. uveitis, sarcoidosis, viral, systemic

mal visual acuity, colour vision may be reduced and a visual field

lupus erythematosus or paranasal sinus disease.

defect present. Formal perimetry is essential, but confronta-

• Demyelination: multiple sclerosis —disc swelling may become

tional fields using a red target can be most informative.

bilateral. Disc(s) swollen or normal in acute phase, and eventually

• Relative afferent pupillary defect.

become pale after recurrent attacks.

• Disc pallor. In severe optic atrophy the entire disc may be pale,

• Hereditary: LHON—may become bilateral.

in many cases only part of the disc (e.g. the temporal part) will be

• Infiltrative: e.g. lymphoma.

affected and subtle disc pallor will be missed if both discs are not

• Infective: e.g. toxoplasmosis, herpes or Lyme’s disease.

compared.

Investigations

Aetiology

• Visual field analysis.

• Hereditary:

• Full blood count (FBC), blood glucose, ESR, CRP, coagulation

—Autosomal dominant optic atrophy: visual acuity may be

screen, infective screen (e.g. toxoplasmosis and Borelia titres),

minimally reduced. Affected family members may vary con-

autoantibody screen.

siderably in abnormalities.

• Blood sent for analysis for Leber’s mutation if suspected.

—Autosomal recessive optic atrophy: poor visual acuity.

• Neuroimaging if demyelination or a compressive lesion is sus-

—Leber’s hereditary optic atrophy (LHON), (see figure).

pected. MRI of the brain and optic nerves should be requested.

• Retinal dystrophy:

• Lumbar puncture if demyelination, neurosarcoidosis or lym-

—Cone dystrophy: very poor acuity, markedly reduced colour

phoma are suspected.

vision, photophobia, central scotoma, nystagmus, typical ERG.

—Retinitis pigmentosa: typical retinal appearance, constricted

Bilateral disc swelling/papilloedema

visual fields and characteristic electroretinogram (ERG).

Clinical features

• Vascular: central retinal artery occlusion (history of angina or

• Visual acuity may be normal or severely reduced.

peripheral vascular disease and sudden profound loss of vision,

• Patients with papilloedema may complain of episodes of unilat-

typical fundal appearance in acute phase —cherry red spot, arteri-

eral or bilateral transient visual loss lasting for a few seconds.

olar attenuation).

These are transient visual obscurations (TVOs) and can be pre-

• Nutritional/toxic: vitamin B₁₂

deficiency

(gradual bilateral

cipitated by changes in posture.

visual loss associated with pins and needles in hands and feet,

• Colour vision is often reduced.

poor diet, reduced colour vision, centrocaecal scotoma), tobacco-

• Enlarged blind spot if the swelling is significant; it will be normal

alcohol amblyopia or drugs (e.g. ethambutol, chloramphenicol).

in mild cases.

• Inflammatory: sarcoidosis, polyarteritis nodosa, contiguous

sinus disease —more commonly present with disc swelling.

Aetiology

• Demyelination (may have past history of typical attacks of optic

• Raised intracranial pressure: SOL, hydrocephalus, benign/

neuritis, and may have other neurological symptoms). It is a

idiopathic intracranial hypertension (BIH/IIH).

common cause.

• Malignant hypertension.

• Compressive: optic nerve glioma or meningioma, orbital tu-

• Diabetic papillopathy.

mour or intracranial tumour.

• Infiltrative papilloedema, e.g. lymphoma.

• Toxic, e.g. ethambutol or chloramphenicol uraemia.

Investigations

• Formal visual field testing.

Investigations

• Visual evoked response/potential (VER/VEP).

• Blood pressure.

• ERG.

• Glucose, FBC and differential WCC, U&E, creatinine and ESR.

• Relevant blood tests depending on clinical history (e.g. vitamin

• Neuroimaging.

B₁₂ and folate levels in a patient who is a vegan and has bilateral

• Lumbar puncture if the MRI is normal and BIH is suspected.

optic atrophy with glove and stocking paraesthesia).

• Visual fields (to monitor blind spot).

• Neuroimaging: MRI optic nerves and brain

Disc swelling

KEY POINTS

Unilateral disc swelling

• Rule out malignant hypertension in papilloedema.

Clinical features

• Urgent CT brain if headache, nausea, papilloedema, normal BP.

• Visual acuity may be normal or reduced.

• MRI if demyelination suspected.

• Reduced colour vision.

Optic nerve disease 103

49 Cranial nerve palsies and eye movement disorders

Neuroanatomy of the 3rd, 4th, 6th and 7th cranial nerves

Nystagmus, e.g. Albinism

Albino - this child's parents

are coloured. Notice the pale

skin and white eye lashes

Levator palpebre

Superior oblique

Albinism

Signs: • infantile nystagmus

Superior rectus

• decreased VA and photophobia

Medial rectus

• iris transillumination

2 types i) oculocutaneous: hair, skin, eyes

Lateral rectus

Pons

Tyrosinase +ve - some pigment as adult

Tyrosinase -ve - never pigment, typical 'albino'

Inferior oblique

ii) ocular: eye pigment affected, hair, skin are normal

Inferior rectus

Needs visual aids, tinted spectacles for glare, sun/skin advice,

3rd nerve

genetic counselling

4th ventricle

4th nerve

6th nerve

Right 4th cranial nerve palsy

Right 3rd cranial nerve palsy

Ptosis globe

'down and out'

Right hypertropia

PCA aneurysm

Bielchowsky +ve

Compensatory head tilt

Posterior

i.e. hypertropia worse

i.e. hypertropia less on tilting

communicating

on tilting to same side

to opposite side

artery (PCA)

Most patients will

adopt a head tilt

Occulomotor/

Pupillomotor

to minimise diplopia

3rd cranial

fibre superficial

nerve

Right 6th cranial nerve palsy

Right 7th cranial nerve palsy

Right internuclear ophthalmoplegia (INO)

Failure of right

abduction

adduction +

left abducting

nystagmus

Patient is attempting to close both eyes

but cannot close right eye

WARNING

Risk of blindness - needs urgent lid lowering

(botulinum toxin) if exposive keratitis and

Aetiology

subsequent eyelid surgery

WARNING

• Vascular (elderly)

• Demyelination of medial longitudinal fasciculus (MLF)

Acquired 6th nerve palsy in patient with

WARNING

shunted hydrocephalus = blocked shunt

in young people

= emergency

Management, investigate, surgery

• Needs MRI brainstem

104 Sub-specialty —Neuro-ophthalmology

Aim

• Watery eye (due to weakness of orbicularis oculi).

• Describe clinical features of IIIrd, IVth, VIth and VIIth cranial

• Sore red eye (due to corneal exposure).

nerve palsies, internuclear ophthalmoplegia (INO), gaze palsies

• Blurred vision secondary to exposure keratitis.

and nystagmus.

• Drooling.

Third nerve palsy

Signs

Symptoms

• Ipsilateral facial muscle weakness, involving the frontalis in

• Double vision —horizontal and/or vertical.

lower motor neurone lesions. The frontalis is spared in upper

• Droopy lid.

motor neurone lesions.

• Enlarged pupil.

• Lower lid ectropion secondary to orbicularis oculi weakness.

• Headache. NB, painful third with pupil involvement —exclude

• Corneal exposure may vary from superficial punctate erosions

posterior communicating artery aneurysm as soon as possible.

to corneal abrasion, and must be treated urgently to prevent ab-

scess formation and endophthalmitis.

Signs

• Ptosis.

WARNING

• Exotropia and hypotropia (globe appears down and out).

May have Vth nerve palsy and corneal anaesthesia.

• Fixed dilated pupil.

• Limitation of elevation, depression, and adduction.

Aetiology

May present with any of these or combination.

• Viral/idiopahtic, e.g. Bell’s palsy

(usually improves sponta-

Aetiology

neously) or Ramsay-Hunt syndrome (herpes simplex infection).

• Ischaemic/vascular (usually pupil sparing due to anatomy of the

• Compressive lesion:intracranial tumour,e.g.acoustic neuroma (may

pupillomotor fibres, and referred to as a ‘medical third’): diabetes

have associated Vth,VIth and VIIIth nerve palsy ) or parotid tumour.

mellitus (DM), hypertension, vasculitis or migraine.

• Vascular/ischaemic: DM, hypertension or vasculitis.

• Compressive lesion (pupil nearly always involved, and referred

• Inflammation, e.g. sarcoidosis.

to as a ‘surgical third’): posterior communicating artery aneurysm,

Internuclear ophthalmoplegia

tumour.

Symptoms

• Trauma.

• Horizontal diplopia.

• Congenital third.

• Inability to coordinate eye movements.

Fourth nerve palsy

Signs

Symptoms

• Failure to adduct the ipsilateral eye.

Double vision —vertical.

• Abducting nystagmus of the contralateral eye.

Signs

Gaze palsies

• Head tilt opposite to the side of the lesion.

Symptoms

• Hypertropia on the affected side.

• Usually asymptomatic.

• Limitation of eye movement down and to the right if left fourth

• May be unable to move eyes together to one side.

nerve palsy, and visa versa.

Signs

• Positive Bielchowsky’s sign, i.e. the hypertropia on the affected

• Failure to move both eyes to one side.

side gets worse on tilting the head to the same side.

• Both eyes may be deviated to one side.

Aetiology

• Trauma is the most common cause of IVth nerve palsy as has

Lesion affecting the supranuclear

(i.e. the neural pathways

the longest intracranial course, is very slender and runs under the

superior to the IIIrd, IVth and VIth nerve nuclei) pathways in the

tentorial edge. Trauma may result in bilateral fourths.

cerebral cortex or brainstem, e.g. stroke, demyelination or SOL.

• Ischaemic/vascular: DM, hypertension or vasculitis.

• Compressive lesion, e.g. intracranial tumour.

Nystagmus

• Congenital.

This is involuntary rhythmic to-and-fro oscillation of the eyes.

Fifth nerve palsy

Symptoms

Corneal anaesthesia.

• Congenital nystagmus is asymptomatic.

• Acquired nystagmus may cause oscillopsia, a sensation of rapid

Sixth nerve palsy

movement or oscillation of the visual environment.Patients describe

Symptoms

it as though looking at an old black and white film where everything

Double vision —horizontal.

flickers or wobbles; others notice only blurred vision, especially if

Signs

gaze-evoked nystagmus.

• Esotropia, worse for distance.

• Limitation of abduction of the affected eye.

WARNING

Refer any patient with nystagmus for prompt assessment by a neuro-

Aetiology

ophthalmologist to exclude intracranial SOL.

• Vascular/ischaemic: DM, hypertension, or vasculitis.

• Invading intracranial or nasopharyngeal tumour.

• Trauma, e.g. fractured skull base.

KEY POINTS

• Painful third —posterior communicating artery aneurysm.

Seventh nerve palsy

• Traumatic sixth —basal skull fracture.

Symptoms

• Internuclear ophthalmoplegia —demyelination.

• Inability to close eyelid (lagophthalmos) and facial weakness.

50 Visual field defects

A detailed knowledge of the neuroanatomy

of the visual pathway can help the clinician

to localize lesions from the field defect found

Left

Right

Left

Right

Optic nerve

temporal

nasal

temporal

Superior arcuate scotoma

field

e.g. glaucoma

Inferior arcuate scotoma

Nasal

e.g. glaucoma

retina

Temporal

Centrocaecal scotoma

e.g. B12 deficiency optic neuropathy

retina

Leber's optic neuropathy

Optic nerve

Chiasm

Superior altitudinal defect

Von Willbrand's

e.g. aion or pion

knee

Inferior altitudinal defect

Optic tract

e.g. aion or pion

Junction optic nerve with chiasm

Lateral

Junctional scotoma

geniculate body

e.g. pit tumour, suprasellar meningioma,

Meyer's loop

craniopharyngioma, supraclinoid aneurysm

Chiasm

Bitemporal hemianopia

Inferior

i.e. pit tumour, chiasmal glioma,

horn of

meningioma, sarcoidosis, MS, abscess

lateral

Optic tract

ventricle

Incongruous left homonymous hemianopia

optic tract lesion, i.e. glioma, MS,

Optic

metastasis

radiation

Meyer's loop

Left superior quadrantinopia

i.e. temporal lobe lesion ('pie in the sky')

Parietal lobe fibres

Occipital

visual cortex

Left homonymous hemianopia

denser below, i.e. parietal lobe lesion

(mnemiopic LP = lower parietal)

Posterior optic radiation

Congruous left hemianopia

Deep occipital cortex

Left homonymous hemianopia with macular

sparing, e.g. SOL, MS, trauma, vasculitis

Macular fibres at occipital cortex

Central scotomatous left hemianopia,

e.g. SOL, MS, trauma, vascular constriction

Retina

Grossly constricted fields - retinal

dystrophy, e.g. RP or severe BIH

106 Sub-specialty —Neuro-ophthalmology

Aims

4 Optic tract

1 Understand the neuroanatomy of the various visual field

A lesion of the optic tract involves the temporal fibres (nasal field)

defects.

from the ipsilateral eye and the crossed nasal fibres (temporal

2 Recognize the causes of different field defects.

field) from the contralateral eye. A lesion completely destroying,

for example the right optic tract, will result in a complete left

Visual field defects

homonymous hemianopia. However, most optic tract lesions are

The most common visual field defects encountered in clinical

partial, and because corresponding fibres from the nasal and

practice include homonymous hemianopia, altitudinal field

retinal fields are not so close together in the tract, the homo-

defect, bitemporal hemianopia, grossly constricted fields, and

nymous hemianopia produced is incongruous (i.e. the hemi-field

enlarged blind spots.

defect from the right eye is not an identical shape to that of the

Note obvious clues that will help you, e.g. a hemiparesis —this

left) (4 on figure).

patient is most likely to have an ipsilateral hemianopia as the

result of a lesion in the contralateral cortex (see figure).

5 Meyer’s loop

A lesion of the optic radiation in the temporal lobe will affect

1 Optic nerve

Meyer’s loop, which contains fibres representing the inferior

A unilateral optic nerve lesion can result in various unilateral field

quadrant of the ipsilateral temporal retina, and the contralateral

defects depending on the nature of the lesion. The shape of field

nasal retina. This results in a superior homonymous quadran-

defect can give a clue to the diagnosis. For example:

tanopia, sometimes referred to as a ‘pie in the sky’ defect (5 on

• Glaucomatous cupping can result in an arcuate scotoma of the

figure).

superior (1a on figure) or inferior field (1b).

• Vitamin B₁₂ deficiency can result in a centrocaecal scotoma (1c

6 Parietal lobe

on figure).

A lesion in the parietal lobe may affect the fibres from the superi-

• Anterior ischaemic optic neuropathy (a swollen disc can be

or quadrants of the ipsilateral temporal and contralateral nasal

seen in the acute phase) and posterior ischaemic optic neuropathy

retina, giving rise to an inferior homonymous quadrantanopia or a

(the disc will look normal in the acute phase) can result in an alti-

homonymous hemianopia denser below than above (6 on figure).

tudinal field defect. This can be superior (1d on figure) or inferior

(1e), depending on which vessels are involved.

7,8 Optic radiation to occipital cortex

• Complete severing of the optic nerve (e.g. as a result of trauma)

Any unilateral lesion affecting the more anterior portion of the

will cause complete ipsilateral visual field loss.

occipital cortex will give rise to a homonymous hemianopia. Be-

cause of the close proximity of the cells representing the corre-

2 Junction optic nerve with chiasm

sponding retinal points, the hemianopia will be congruous (7 on

Because of the arrangement of nerve fibres in the optic nerve and

figure), unlike the incongruous hemianopia seen with an optic

chiasm, a lesion pressing on the visual pathway at the junction of

tract lesion (the more posterior the lesion, the more congruous the

the intracranial optic nerve and the chiasm can produce a charac-

field defect). Because the macula has a large representation in the

teristic field defect (2 on figure), known as a junctional scotoma.

occipital cortex, and a dual blood supply, the central 5° of vision is

Such a field defect results because the lesion compresses both

maintained in an anterior cortical lesion —macular sparing (8 on

fibres from the nasal fibres (serving the temporal visual field) of

figure).

the ipsilateral optic nerve and the inferonasal fibres (superotem-

poral field) from the contralateral eye in Willbrand’s knee.

9 Macular fibres at occipital cortex

A posterior lesion affecting one side of the occipital cortex will re-

3 Chiasm

sult in a homonymous hemianopic scotomatous field defect (9 on

A lesion pressing on the optic chiasm, such as a pituitary tumour,

figure).

will result in damage to the nasal fibres from both eyes as they

cross the midline, and therefore results in a bitemporal hemi-

KEY POINTS

anopia (3 on figure). Early on, if the lesion is only minimally com-

• Bitemporal hemianopia indicates a chiasmal lesion —most commonly a

pressing the chiasm, the field defect will be very subtle, and may

pituitary tumour.

only be picked up by using a red target (the individual will have

• Left homonymous hemianopia indicates a right cortical brain lesion.

red desaturation in the affected field —this is true for all subtle

• Altitudinal field defect is typical of anterior ischaemic optic neuropathy.

lesions).

Visual fields defects 107

Appendix: Red eye

Signs and symptoms of different causes of a red eye

Signs and

Subconjunctival Corneal

Acute

Corneal

Symptoms

Conjunctivitis

haemorrhage

abrasion

Allergy

Iritis

glaucoma

ulcer

History

Family/

Trauma,

Injury

Hay fever,

Nil or other

Change of

Contact lens,

friend

hypertension

asthma,

inflammatory

lighting

injury

eczema

disease

Sensation

Grittiness

None, mild

Pain,

Itching

Pain,

irritation

photophobia

photophobia,

photophobia

nausea

Vision

Normal

Decreased

Normal

Decreased

(if central)

Discharge

Purulent/clear

None

Tearing

Mucus

Tearing

Tearing and

mucopurulent

Pupillary light

Brisk

Sluggish

Mid-dilated

May be

reflex

and fixed

sluggish

Conjunctival

Diffuse, tarsal

Localized,

Diffuse

Diffuse, tarsal

Circumcorneal Diffuse

Circumcorneal

injection

area

bright red

area

Corneal

Clear

Stains with

Clear

Keratic

Cloudy

Stains with

appearance

fluorescein

precipitates

cornea

fluorescein

Intraocular

Normal

Normal or

Markedly

Normal or

pressure

elevated

Basic

Hygiene, may

Reassurance,

Padding,

Topical

Ophthalmic

management

require topical

check blood

topical

antihistamine

referral

antibiotics

pressure

antibiotics

108 Appendix: Red eye

Index

Note: page numbers in italics refer to figures, those in bold refer to tables.

Acanthamoeba

capillary haemangioma 52, 53

conjunctival-corneal intraepithelial neoplasia

corneal ulcer 33

capsulotomy, YAG laser 76

(CCIN) 66, 67

keratitis

66, 67, 69

Cardiff cards 46, 47

conjunctivitis 8

accommodation 20, 21, 22, 23

cataract 27, 33, 44, 45

allergic

34, 35, 65

age 22

assessment 72, 73

vernal/atopic 52, 53

loss with cycloplegia 30, 30

causes 72

children 52

range 23

congenital 45, 51

giant papillary 69

acetazolamide 83

surgery 8, 9, 74, 75, 76, 77

HIV infection 98, 99

aesthenopia 45

cavernous haemangioma 62, 62

infective 32, 33

age

central areolar choroidal dystrophy

perennial allergic 65

accommodation 22

central visual field loss 25

post-cataract surgery 76