Preschool children (3-5 years): Visual acuity can be assessed using a modified technique. The most successful and accurate technique is the Linear-Stycar technique. (Linear stycar-click to view) The patient matches, on a key-card, the letters displayed on a vision chart at 6 metres.

Preverbal children: – The observation of behavioural patterns is the simplest method of assessment in this age group. Further information can be gained by fixation and pursuit patterns when appropriate visual targets are shown. Pupillary responses to light and optic kinetic nystagmus can also be used.

At 2-4 weeks an infant will fixate and follow a light.

By 5-6 weeks a large object will be followed.

By 5-6 months small objects will receive attention. Small toys, attractive objects, or sweets may be used to determine visual responses. Click Visual Targets

Preference of fixation with one eye is an indication of better vision in that eye. A strabismic patient will alternate the fixing eye if vision is equal.

THE OBJECTIVE ASSESSMENT OF VISION

Visual acuity can be assessed objectively by using

- The Visually Evoked Response

- Or Preferential looking techniques

The Visually Evoked Response VEP in detail

This is an electro-encephalographic response evoked by a visual stimulus and recorded by electrodes over the occipital cortex. An estimation of visual acuity may be made. Using this technique it has been estimated that infant visual acuity approaches the Snellen equivalent of 6/6 by the age of 4 – 6 months.

A VEP demonstrated

Preferential Looking
The infant’s preference for looking at a plain or patterned screen is assessed. The visual angle, subtended by the smallest stimulus, viewed at an incidence considered greater than chance allows visual acuity to be estimated.

Demo of preferential looking

Visual Acuity in infancy measured by P.L. is not as high as measured with the V.E.P. Both techniques are of value. P.L. requires an alert, active, involved child while the VEP can be performed even in the absence of cooperation or involvement by the patient.

REFRACTION IN CHILDREN

Infant’s eyes tend towards the hypermetropic side of normal. The incidence of myopia is low in preschool children but increases in childhood. Click for causes of myopia

Astigmatic refractive errors are common in neonates but frequently resolve within the first six months of life.

Refraction of children of all ages is possible. This is performed following the instillation of drops (atropine or cyclopentolate) to paralyse the ciliary muscle. This enables a measurement of the ocular refractive state to be made objectively using the retinoscope. Subjective refraction becomes practicable from the age of 7 years. (click on pictures below for enlargement)

Hypermetropia Myopia Astigmatism click pictures to enlarge

Correction Of Refractive Errors

Spectacles can be prescribed from an early age if high myopia is present or if hypermetropia precipitates an accommodative squint. Small refractive errors do not require spectacle correction. Children are not assisted in any way by the prescription of weak spectacles.

Where the refraction is different in each eye amblyopia may occur (anisometropic amblyopia), requiring the prescription of spectacles.

Contact lenses

Daily wear soft contact lenses are well tolerated by older children and can be prescribed for recreational or cosmetic purposes.

Extended wear soft contact lenses are suitable for the correction of gross refractive errors in infancy (see Congenital Cataract). They require removal for cleansing on a regular basis.

Pinhole Vision

In older children the best corrected vision may be determined by testing visual acuity through a pinhole. If vision is not improved in this manner the visual loss is not due to refractive error.

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STRABISMUS

Synonym – squint, turned eye, cross eyes.

Definition – a condition bin which there is a disturbance of the relative position of the optical axes of the eye so that one fovea is deviated from the object of regard.

Incidence – 3 –5 % of normal children are strabismus. But more than 50% of Cerebral Palsy children have strabismus. Similarly the incidence is high in hydrocephalus.

Types of Strabismus

1. Incomitant

The angle of deviation varies in different directions of gaze. This occurs most commonly where there is paralysis of one or more extraocular muscles.

Causes: –

a. Neurological - due to lesions of 3^rd, 4^th, or 6^th cranial nerves caused by:

- Trauma- Tumour – (Intracranial)

- Infection

- Raised Intra-Cranial Pressure (6th Nerve Palsy)

b. Muscular – Direct involvement of the extraocular muscles by

- Trauma

- Tumour of the orbital or periorbital tissue

- Infection

- Muscular Anomaly – Dystrophy etc.

c. Neuro Muscular – Myasthenia Gravis

d. Congenital Conditions:

- Duane’s Retraction Syndrome -

- Browns Syndrome

- Moebius Syndrome

In all these states the angle of squint varies, becoming maximal when an attempt is made to gaze in the direction of action of the paralysed muscle. In children the eyes may fail to realign following temporary paralysis and a permanent comitant squint may occur.

Duane’s Syndrome – The involved eye is unable to abduct and on adduction is retracted into the orbit.

Brown’s Syndrome - The inability to elevate the eye in adduction

Moebius Syndrome – Combined 6^th and 7^th nerve palsies. Return to index

2.Comitant Strabismus

The angle of squint is equal in all directions of gaze. There is no abnormality of function of extra ocular muscles but instead, incorrect co- ordination of binocular muscle function is present.

Types Of Concomitant Strabismus

- Esotropia (Convergent Squint) optical axes converge (A convergent squint)

- Exotropia (Divergent Squint) optical axes diverge (A Divergent squint)

- Hypertropia – (Vertical Squint) – One optical axis is deviated vertically.

- Latent Strabismus becomes apparent only on dissociation of the vision of the eyes (eg on covering one eye) and is termed a phoria (exophoria, esophoria, hyperphoria). This may become overt with fatigue, illness, or with lack of attention.

Causes of Comitant Strabismus

Hereditary : a familial predisposition to develop strabismus may be inherited as an autosomal dominant trait.
Sensory Deprivation – A blind eye has no incentive to remain aligned. Therefore any condition which results in markedly reduced vision may cause a squint. E.g. Corneal Scarring, Cataract, Opacity of the Refractive Media, Retinal Lesion e.g. – Retinoblastoma, Retinal Detachment, Optic Atrophy, High Refractive Error.
Secondary To Paralytic Squint – Children have a tenuous hold on single binocular vision therefore they frequently do not manage to redevelop this following a paralytic squint.
Accommodative – The close anatomical and physiological link between accommodation and convergence causes the frequent excessive convergence (esotropia) in children who are hypermetropic i.e. because these children need to accommodate excessively to obtain clear vision they often break down and develop a convergent squint.
Unknown – no cause for the occurrence of strabismus will be found in many cases.

WHY IS STRABISMUS STRESSED BY OPHTHALMOLOGISTS?

The reasons are multiple:

1. The Incidence Of Strabismus- a common condition

- 3-5% in the normal population

- > 50% in Cerebral Palsy and Hydrocephalic patients

2. Common Misconceptions:

- “The child will grow out of his squint”

- “ Nothing can be done before the age of 2,3 or even 4 years”

- “ Learning difficulties may be cause by a squint”

- That the child only needs “some eye exercises”

The Truth:

Children rarely grow out of squints! The misunderstanding arises because an apparent squint due to eyelid shape (e.g. prominent epicanthic folds) frequently becomes less obvious with age, thus confusing parents and perpetuating the myth. Epicanthic fold & Squint (The child on the left of this picture has a true squint -see the light reflections- but the other child has straight eyes)

Squints can be adequately measured, assessed and corrected at any age! The importance of this early management is clear when one considers that loss of vision caused by a turned eye may become permanent!

Some of the organic causes of squint (eg optic atrophy and retinoblastoma) may require early diagnosis to prevent catastrophe!click picture to enlarge

Squint and Learning Disability – Major studies have shown incidence of eye movement disorders is not increased in children with learning problems. There appears to be no correlation between squint and learning disabilities!

Eye exercises play a very minor role in the management of strabismus.

3. THE IMPORTANCE OF STRABISMUS Return to index

What causes a squint?

Sensory deprivation must always be excluded as a cause of strabismus. Potentially fatal conditions such as Optic Atrophy – resulting from an intracranial space occupying lesion (Brain Tumour) – or Retinoblastoma frequently present as a squint. As may Retinal Detachment, Lens opacity, Vitreous Haemorrhage or Toxoplasmosis Retinopathy.

All children with a unilateral squint must be fully examined to exclude these organic disorders if catastrophe is to be avoided! The possibility that a squint may be secondary to other neurological disorders (e.g. raised intracranial pressure) must also be excluded.

What effect does does a squint Have?

When one eye deviates immediate brain confusion results. There is then immediate and absolute suppression of foveal vision of the deviated eye (The eye is turned off). The object of regard projects to the wrong point on the retina – thus double vision occurs.

After visual maturity is reached (age 7 years) this diplopia is permanent. But young children are able to ignore this second image – by suppressing it – and they avoid diplopia.

They pay a price for this. Because they are not using the eye correctly in this formative period this causes loss of vision which becomes permanent if not eliminated while the patient is visually immature. i.e. Amblyopia.

4. AMBLYOPIA-. diminished visual acuity not correctable with spectacles, in the absence of organic pathology.

Click for Further discussion of amblyopia

Incidence of Amblyopia – 3-5% in the general population.

Amblyopia is caused by a disturbance of foveal visual stimuli – either displacement of the image in strabismus i.e. Strabismic amblyopia or a defocused image with media opacities (vitreous, lens, or cornea) – i.e. Deprivational amblyopia or unilateral refractive error – i.e. anisometropic amblyopia.

Amblyopia is amenable to therapy provided such therapy is prompt, early and continuous until visual maturity is attained. It is rarely successful after the age of 7 years.

The earlier the onset of amblyopia the denser and the more rapid is its occurrence.

The earlier its management the more rapid and more complete its resolution.

Thus the early diagnosis and correction of strabismus will result in better prevention and control of permanent visual loss through amblyopia.

MANAGEMENT OF STRABISMUS

This involves –

1. Confirming the presence of the Squint

2. Confirming the type of squint

3. Establishment of the cause of the squint

4. Eliminating the cause if possible eg – organic , refractive

5. Treat Amblyopia if present

6. Straighten the eye

The clinician requires a history and examination :-

History :

- What do parents see?

- Duration and frequency of the squint

- Is it constant?

- Is it greater for near or distance?

- Is it always in the same eye?

- Is there a family history of strabismus?

- Is there a family history of neurological disorder?

This history will help eliminate pseudo squint of epicanthic folds.

A convergent squint seen principally when reading will suggest an accommodative squint.

An intermittent divergent squint is frequently worse for distance.

An alternating squint suggests that there is no amblyopia present and makes an organic cause unlikely.

Examination (A.) Initial Medical Assessment

- Visual acuity – assessed as discussed.

- Extra Ocular Movements - The ability of the eyes to move to the Cardinal Points of Gaze is assessed to demonstrate paralytic strabismus.

- Corneal Reflections – The symmetry of the reflections, on the cornea, of a narrow light beam is assessed. Each millimetre of deviation from the centre of the cornea is equivalent to 7 degrees deviation of the eye.

- Cover/Uncover Test - This test is used to detect the present of a tropia or a phoria. It may be used together with a prism to measure the angle of deviation. The test is performed with the patient fixating a detailed object at distance (6m) and near (35cm). When the non – deviated eye is covered the other eye will move to take up fixation i.e. moves in, If Exotropic or moves out, if Esotropic. If the deviating eye is covered no movement will be seen. If a phoria exists no movement will be seen on covering either eye but the covered eye deviates while occluded and recovers when uncovered.

- Ophthalmoscopy – To exclude organic ocular disorder which may result in a sensory defect and secondary strabismus. Direct ophthalmoscopy

At this stage of the examination it is possible to determine whether a squint is present.

If strabismus is diagnosed or if uncertainty exists than referral to an Ophthalmologist should be undertaken IMMEDIATELY.

Examination (B). Ophthalmic Assessment

Includes examination as discussed above. The following examinations are then carried out.

- Refraction - test for glasses (following Cycloplegic Drops) This will demonstrate any refractive error

- Ophthalmoscopy including Indirect Ophthalmoscopy (while pupils are dilated) To exclude intra-ocular disorders, as discussed

Treatment :

If significant refractive error is present (particularly hypermetropia) spectacles are prescribed. Spectacles may fully correct an accommodative squint.
If amblyopia is present this is treated by occluding the fixating eye until visual acuity is equal in each eye.
Surgery: This is undertaken, when steps 1 & 2 are completed. To correct any residual angle of squint. The extra-ocular muscles are shortened or lengthened surgically to correct the angle of strabismus.
Follow up: until the possibility of recurrence of strabismus or amblyopia is assured

When to operate:

When the angle of squint can be accurately measured – anytime after 5 months of age. There is no advantage in delaying the procedure further. For if an infant is to gain binocular fusion this is only possible prior to the age of two years. The surgery is routine, complications are rare and minor. More than one surgical procedure may be required.

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PTOSIS

Definition – Drooping of the upper eyelid

Aetiology – Congenital - Idiopathic, Hereditary

- Acquired - Traumatic

- Mechanical

- Neurogenic – 3^rd nerve palsy

- Sympathetic palsy – Horner’s Syndrome

- Myasthenia gravis

If total ptosis exists deprivational amblyopia could occur. This is rare. But anisometropic amblyopia is common, because of associated astigmatism.

For Further discussion of amblyopia

Management – Test vision and perform a refraction to exclude amblyopia

Monitor vision and refraction

Many children with congenital ptosis do not close their eyelid fully while sleeping.

Surgery at 3 – 4 year- earlier if ptosis is obstructing vision.

Surgery-

Partial Ptosis- the muscle of elevation –Levator Palpebrae Superioris can be effectively adjusted to correct the eyelid height. This operation is performed through an incision which is placed in the eyelid skin crease. It is effectively hidden when the eye opens.

This surgery is very effective. In 95% of cases the eyelid elevates to the desired height postoperatively. Rarely it may be necessary to adjust the eyelid position to attain maximal correction postoperatively

Commonly the tendency to sleep with the eyelid open may be exaggerated in the early postoperative period.

Possible Complication of Surgery – corneal exposure may occur- an extremely rare complication in children.

Total Ptosis: Surgery to correct this involves attaching the eyelid muscles to the muscles of the forehead- Frontalis Sling Procedure. The ideal material

For this is fascia from the patient’s own thigh. This Fascia is a living graft and grows with the patient becoming incorporated in the eyelid tissues and results in a permanent cure. Various artificial materials are available for use but they all have limited effectiveness. Their use should be limited to correction of total ptosis in infants when fascia cannot be used. In these cases revision of the surgery using living fascia is usually necessary at a later age. Return to index

CONJUNCTIVITIS

Conjunctivitis in older children presents no unusual diagnostic problems. Aetiological factors may be:-

1. Bacterial Conjunctivitis click picture to enlarge

Clinical Findings

-Red eyes – usually bilateral, sore (but not painful)

- Muco-purulent discharge

Diagnosis - Gram stain and culture

Therapy - Eye toilets + Local antibiotic drops second hourly

2. Viral Conjunctivitis (adenovirus) Typical Case

Clinical Findings

- Frequently unilateral initially

- Red eye

- Watery discharge

- Tender preauricular lymph node

- Follicles visible on tarsal conjunctival

Diagnosis – Clinical features + Culture (e.g. Adeno Virus)

Therapy - Supportive

- Hot Spoon bathing

3.Allergic Conjunctivitis- Spring catarrh, vernal conjunctivitis

Cases of Vernal conjunctivitis and keratitis

Clinical Findings

- Itchy eye, Rubbing of eyes

- Watery discharge

- No injection

- Cobblestone papillae on tarsal conjunctival

- Beware of Photophobia or reduced vision –This signifies corneal involvement and possible serious loss of vision!

Diagnosis – Eosinophils in conjunctival scraping

Therapy - Minor case –trial with vasoconstrictors- Naphcon A, Albalon A

- Mast Cell Stabilisers- Lomide, Opticrom. Effectivity is limited. Drops must be used regularly 3 or 4 times daily even when asymptomatic to stabilise Mast Cells. They are of no value used only when symptoms occur because they take some time to have an effect. Compliance with these medications is extremely poor and I find their practical value is minimal. Newer medications in the same spectrum promise much more and I am trialling G Patenol, yet to be released in Australia.

-Local steroid drops- Continue to be the most effective available topical medication for severe Vernal conjunctivitis. Their use requires monitoring because of their possible effect on Intra Ocular Pressure. I have often seen vision lost as a result of failure to control Allergic Keratoconjunctivitis because of fears regarding steroid use. Steroid raised pressure in children is rare, I have not seen vision lost from this complication in childhood. Monitor the dose of steroids, adjusting the dose according to the response. There is usually a gradual reduction in the number of applications required and eventual cessation in teenage life.

4. Neonatal Conjunctivitis Typical case

Conjunctivitis in the neonate may be a sight threatening condition.

Severe Purulent conjunctival infection in this age group can result in corneal involvement and even rupture.

Aetiological Agents:

- Gonococcal – (classical but rare) culture

- Other Bacteria – culture, gram stain

- Chlamydia – smear (new test)

- Herpes simplex – culture

Therapy :-

- Admit to hospital

- Hourly eye toilets

- Hourly antibiotic drops

- Appropriate systemic antibiotics

Prompt adequate therapy in patients with neonatal conjunctivitis should prevent corneal complication and permanent visual impairment.

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NASOLACRIMAL DUCT OBSTRUCTION

Normal canalisation of the nasolacrimal ducts may nor occur until 4-6 months of age. Tear overflow and secondary infection may result from this obstruction. The nasolacrimal duct system drains excess tears from the eye into the nose. It consists of an opening-punctum, initial tube- canaliculus, a reservoir- lacrimal sac, final tube- nasolacrimal duct.

The obstruction in infancy is in the duct. Tears stagnate in the sac and bacteria result in a muco-purulent discharge to be accumulate and overflow back into the conjunctival sac.

Clinical Findings -watery, discharging eyes in first few months of life click on picture to enlarge

- overflow of tears

- no conjunctival redness

Different Diagnosis

- acute conjunctivitis (red, discharging eye)

Management

- Reassure parents of natural history

- Massage over lacrimal sac

- Local antibiotic drops – for secondary infection

- If not resolved at 6 – 10 months of age the obstruction may be overcome by passing a fine probe through the tear passages, usually under a general anaesthetic.

- If performed prior to 12 months of age 95% are corrected with a single probing. after 12 months this decreases to 70%. By 2 years of age the cure rate has reduced further.

- Severe infection may prompt earlier intervention to prevent fibrosis and chronic occlusion, for this may require major surgical intervention. Infection in the tear sac may result in an abscess forming- acute dacryocystitis- requiring immediate treatment.

- If a probing does not improve the condition a silicone tube is placed in the nasolacrimal system for a number of weeks to maintain its patency. This procedure is more complex than a probing.

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The Cornea

Clinical Features

A corneal lesion from any cause results in :

- pain, photophobia and a red eye

- Vision may be reduced

Examination

- Inspection using magnification may reveal corneal opacities, or a corneal foreign body.

- Inspection after staining with fluorescein will demonstrate any epithelial defect.

Lesions include:

Herpetic Keratitis (Dendritic Ulcer): Herpes simplex infection results in a branching ulcer

Therapy – Oc Acyclovir

Complications - recurrence

- corneal scarring

- iritis and deep keratitis

NOTE: Corticosteroids are contra indicated for they cause rapid progression and can lead to corneal perforation.

Corneal Abrasion: A geographic area of epithelial loss.

Therapy – occlusion with a firm pad results in rapid resolution

Corneal Foreign Body

Will be noted on inspection or following fluorescein stain

Therapy – Amethocaine drop for anaesthesia and removal with a fine hypodermic needle

- Occlude until ulcer has healed

Viral Keratoconjunctivitis

Associated with the conjunctivitis may be a punctate keratitis with subepithelial infiltrates

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INFLAMMATION OF THE EYELID

Blepharitis

Definition – inflammation of the lid margins may be associated with conjunctivitis

Aetiology – Staphylococcus

- Parasites (uncommon) Pediculosis, Demodex

Therapy - Remove parasites

- Betadine toilets

- Local steroid and antibiotic ointment applied at night. This may be needed long term as the condition tends to recur.

Hordeolum –(Stye)click picture to enlarge

Definition - An abscess in a lash follicle

Therapy - Drainage by removing the lash

- Hot spoon bathing for comfort

- Local antibiotics to prevent recurrence.

Chalazion (Meibomian Cyst)click picture to enlarge

Definition - Chronic infection in a Meibomian glad. It may develop acute suppuration infection. A lump is seen over the tarsal plate

Therapy - If acutely inflamed – hot spoon bathing and antibiotics to reduce cellulitis. - Chronic cysts – incise and curette.

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ORBITIAL INFLAMMATIONS

Preseptal Cellulitis click on picture to enlarge

Inflammation of eyelid tissues results from trauma or spread of local infections.

It is necessary to observe closely for spread. Treat with Oral Antibiotics.

Orbital Cellulitis

- i.e. inflammation of orbital tissues behind the orbital septum. This has very serious consequences if not managed quickly. spread of infection may result in Cavernous Sinus Thrombosis or Meningitis.

Aetiology - secondary to acute sinusitis

- secondary to ocular inflammation

Both results in proptosis and some limitation of ocular movement. Where the aetiology is extra – orbital the eye will be white and quite – the opposire in ocular infection

Therapy - treat the causative infections

- systemic antibiotics

- Surgical drainage of the sinus maybe necessary.

These children require admission to hospital because of the potential hazards to vision due to optic nerve compression, the complication of cavernous sinus involvement or meningitis.

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UVEAL INFLAMMATIONS

Anterior Uveitis – Iritis

Aetiology - often unknown

- auto immune disorders e.g. Stills’ Disease or ulcerative colitis

- secondary to corneal lesions

- tuberculosis, sarcoidosis

Acute Iritis

- red, painful eye

- vision often reduced

- miosis (pupil may be irregular due to adhesions to the lens)

- cells visible in anterior chamber

- deposits of white cells on corneal endothelium

Therapy

- local steroids (Prednisone drop)

- mydriatics (atropine 1% drops)

Complications

- secondary glaucoma

- cataract

- vision loss

Chronic Iritis

Is often insidious but the examination demonstrates the features as above but the eye is white.

Chorio–Retinitis

Toxoplasmosis Retinitis –usually a focal chorio-retinal scar, frequently at the macula.

Toxocara Canis Retinitis – ocular manifestation of visceral larva migrans – nematode larva. A peripheral retinal granuloma may be seen associated with vitreo-retinal fibrosis and traction.

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LENS ABNORMALITIES

Congenital Cataracts click picture to enlarge

Definition – A cataract is an opacity of the lens.

Cataracts occur infrequently in childhood but early diagnosis and management is essential

Common Aetiological Factors:

- Hereditary – Dominant, recessive or x-linked

- Infective – Intrauterine Rubella,

- Cytomegalic Virus

- Metabolic – Diabetes, Galactosaemia

- Trauma

Diagnosis: Altered red reflex on ophthalmoscopic examination.

This examination is essential, in all infants, in the first week of life.

Management Of Congenital Cataracts – In recent years the importance of early extraction of congenital cataracts has been emphasized. Dense cataracts cause dense deprivational amblyopia. If relatively normal foveal vision is to be obtained these cataracts must be extracted and vision corrected with appropriate lenses by 3 months of age if possible. This management today includes simultaneous cataract extraction and implantation of an intraocular lens.

Click For further details

Early DIAGNOSIS, SURGERY and CORRECTIVE LENSES are essential for good vision.

Unilateral Cataracts present a major problem of anisometropia. Again early extraction, correction with Intraocular lens, contact lens together with therapy to overcome deprivational amblyopia results in an occasional moderate visual result. But, the road is long and difficult for the child, the parent and the physician! Surgery for unilateral cataracts should not be recommended lightly.

Note: Examine all neonates for cataracts. Extract and refract by 2 months.

Dislocated Lenses

If the Lens zonule (ligament which holds the lens in place) is disturbed dislocation may occur.

This results in reduction of vision and sometimes secondary glaucoma. Lens dislocation may occur following trauma but it is associated with a number of systemic conditions-

MARFAN’S SYNDROME Marfan’s

MARCHESANI’S SYNDROME

EHLERS-DANLOS’ SYNDROME

HOMOCYSTINUREA

SULFITE OXIDASE Deficiency

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CONGENITAL GLAUCOMA

Definition: Elevation of intraocular pressure resulting from abnormal development of the angle of the anterior chamber

Synonym – Buphthalmos

The soft ocular tissues of infancy respond to an elevated pressure by expanding. This results in an enlarged eye.

Aetiology – anomalous development of the angle of the anterior chamber. It may be associated with other abnormalities of the eye e.g. ANIRIDIA

Symptoms - photophobia

Signs - enlarged corneal diameter

Complications - reduced vision occurs due to corneal changes or to optic atrophy

- Delay in recognition results in permanent corneal changes and loss of vision.

Management - Surgical

Note: - Beware of photophobia in an infant!

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NEOPLASMS

Retinoblastoma click picture to enlarge

Definition: A malignant tumour of the retinal receptor cells

Incidence - 1 out of 23000 live births

- sporadic or dominantly inherited

- If bilateral, inherited or due to germ mutation may be transmitted

-Unilateral – probably sporadic

Presentation – Strabismus

- White pupil

Examination - The entire retina of each eye must be examined by indirect ophthalmoscopy following dilation of the pupil.

- X-ray demonstrates the presence of calcium

- Examination of siblings is important

- Chromosome abnormality is occasionally seen

Treatment - Enucleation of one eye and irradiation of the second eye, if involved, unless diagnosis is certain from family history then bilateral irradiation.

Prognosis - 80% survival if prompt early treatment

- 20% survival if tumour has spread to optic nerve or orbit.

Leucocoria click picture to enlarge

Definition – white pupil

Retrolental lesions may if large enough, reflect light out of the eye causing a white pupillary reflection. Cataracts can be distinguished from a retrolental lesion.

Differential Diagnosis

- Retinoblastoma

- Retrolental Fibroplasia

- Persistent Hyperplastic Primary Vitreous

- Congenital Toxoplasmosis

- Toxocariasis

- Coats Disease

- Chorioretinal Colobomas

Orbital Neoplasms

Infrequent in childhood. They include:-

Rhabdomyosarcoma

Definition - A Malignant tumour arising in the first ten years of life. Usually unilateral. It causes unilateral proptosis. Its rapidity of growth may simulate infection

Diagnosis – CT Scan and biopsy

Management – Radiation and Cytotoxic drugs

Prognosis - > 80% 5 years survival

Leukaemic Infiltrations – usually bilateral

Metastatic Neuroblastomas – lid ecchymoses with or without proptosis

Inflammatory Pseudotumour – presents with proptosis

Diagnosis -Biopsy

-CT Scan

Therapy – Corticosteroids – give a dramatic response

Histiocytosis X And Infantile Xanthogranulomas

Diagnosis – Bony defects on X-ray

-Biopsy

Optic Nerve Glioma – a benign tumour resulting in decreased vision proptosis and enlargement of the optic foramina. If confirmed to the optic nerve prognosis is good. If the chiasm is involved the prognosis is much worse.

Craniopharyngioma

This cystic tumour causes chiasmal compression causing in visual field defects and optic atrophy.

Treatment - surgery and radiotherapy

- monitor visual fields and optic nerve function

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RETINA

Retinitis Pigmentosa An inherited disorder of pigment epithelium and receptor cells (recessive, dominant or x-linked inheritance)

Clinical Findings

- Night blindness, constricted visual fields

- Often good central vision, but constricted fields

- Retinal pigmentation – bone spicule

- Optic atrophy and retinal artery attenuation

- Electroretinogram abnormal from an early age- before there is any other evidence of abnormality erg information

Management No therapy is available. retinitis pigmentosa information

Associated disorders

- Refsum’s Syndrome – R.P., deafness, elevated blood phytamic acid

- Bardet Biedl Syndrome – R.P., & obesity metal retardation, hypogonadism,

- Ushers syndrome – R.P. & deafness

Central Retinal Degenerations

Stargardts Muscular Dystrophy – decreased vision, pigmentary macular change (“beaten- bronze” appearance) with or without yellow fleck deposits. Recessively inherited.

Vitelliform Macular Dystrophy – an “egg yolk appearance” at the macula. Dominantly inherited.

Retinopathy Of Prematurity

Infants born prematurely have an incompletely vascularized retina. The exposure of this immature retina to high oxygen concentrations may result in abnormal vascular development.

In the acute phase an arterio-venous mesenchymal shunt is present in the peripheral retina at the junction of the vascularized and nonvascularised zones. This may be visible ophthalmoscopically as an elevated ridge.

If the condition progresses intra vitreal fibrovascular proliferation may occur progressing even to an acute exudative retinal detachment.

Chronic changes secondary to contracture of this fibrovascular tissue may result in retinal folds, dragging of the optic disc, and even traction retinal detachment. This retinal detachment and fibrous tissue amt be seen as a white retrolental opacity – retrolental fibroplasia.

Infants at risk require ophthalmic examination . Those at risk are – less than 1500 gms at birth, severely ill babies, especially babies who required supplemental oxygen.

Supplemental oxygen levels should be restricted to a that level which is adequate to maintain cerebral and other vital functions. Arterial oxygen levels must be monitored. But even with the greatest care retrolental fibroplasia still occurs.

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SYSTEMIC DISEASES AND THE EYE

Wilson’s Disease – Kayser – Fleischer ring in cornea

Muco – Polysaccharidoses - corneal clouding

- pigmentary degeneration of the retina (abnormal E.R.G.)

-optic atrophy

Sphingolipidoses - lipid deposition in corneal epithelium

- lens opacities

- cherry red spot at macula (Tay-Sachs)

Congenital Rubella - cataracts

-pigmentary retinopathy

Juvenile Rheumatoid Arthritis - Chronic iritis

Lupus Erythematosis - Retinopathy – multiple soft exudates

Alports Syndrome - Anterior Lenticonus

- Cataract

Albinism - Transillumination of iris click for more information on albinism

- Macular Hypoplasia

- Nystagmus

Ceroid Lipofuscinosis - Retinal degeneration

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OCULAR DEVELOPMENTAL ANOMALIES

Hamartomas – normal tissue elements in abnormal proportions or configurations e.g. Naevi, Haemagiomas, Lymphangiomas.

Phakomatoses – Disseminated Hamartomas e.g. Tuberous Sclerosis, Sturge Weber Syndrome and Neuro fibromatosis.

Choristomas – Normal tissue elements in abnormal sites e.g. Dermoids.

Colobomata – Areas of absent tissue occurring where foetal clefts fail to close e.g. Iris, Chorioid, Optic Disc & eyelid (Goldenhar or Treacher Collins).

Other abnormalities of Ocular Development may cause a combination of anatomical and physiological disruptions.

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NEURO-OPHTHALMOLOGY

Optic Atrophy

Aetiology in Children

- Hydrocephalus

- Hereditary (dominant, recessive, or x-linked)

- Space occupying lesions (intracranial, orbital)

- Heavy metal poisoning (lead, arsenic)

- Secondary to papilloedema

- Cerebral Degenerations

Clinical Findings

- Diminished vision

- Pupil reaction to light reduced

- Marcus Gunn Pupil – (consensual reaction greater than direct)

- Pallor of optic disc and reduced vessels on disc.

- Visual field changes

- Abnormal visual evoked potential

- (of particular value to children too young to measure vision or to perform visual fields.)

- C.T. Scan is necessary

Note: Optic Atrophy requires a full neurological investigation

Papilloedema

Definition – swelling and vascular congestion of the optic disc – with blurring of disc margins, haemorrhages and venous dilatation.

Aetiology

- Hypertension – always associated with severe hypertensive retinopathy

- Raised intracranial pressure – vision will be normal and visual fields show only enlargement of the blind spot in the early stages.

Differential Diagnosis

- Papillitis – an identical appearance of the optic disc. But vision is profoundly disturbed – (central scotoma)

- Toxic optic neuropathy

- Demyelination

-Pseudopapilloedema – blurred disc margins due to hypermetropia. No venous congestion.

A congested swollen disc without raised intracranial pressure, also occurs with chronic cyanotic cardiac and pulmonary disease due to carbon dioxide retention.

Management of Papilloedema

Full neurological examination and investigation is required to exclude possible causes of raised intracranial pressure.

eg – Space occupying lesions

- Infective causes

- Benign intracranial hypertension

If papilloedema is not relieved permanent loss of vision and constriction of fields (with optic atrophy) may result.

Abnormal Pupillary Reactions

Anisocoria – ( unequal pupils) is present in about 20% of the normal population

Pathological Anisocoria

- Large pupil – 3^rd nerve paresis – associated with muscle palsies

- Small pupil – sympathetic paralysis (Horner’s Syndrome)

- Mydriasis may also occur because of eye drops, some plants and trauma.

Horner’s Syndrome – Miosis, Ptosis, Enophthalmos, anhydrosis

If this occurs before two years of age Heterochromia of the Iris results.

Congenital Horner’s commonly occurs due to birth trauma but occasionally may be due to a mediastinal tumour (eg neuroblastoma.)

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