Ординатура / Офтальмология / Английские материалы / Moorfields Manual of Ophthalmology_Jackson_2007

■C. trachomatis : erythromycin syrup 50 mg/kg/day in four divided doses for 2 weeks. A second course may be required.

■Treat neonatal herpes infection with systemic aciclovir.

Follow–up In general, review outpatients once weekly until improving. If infection recurs, reconsider Chlamydia even if initial testing was negative. Observe for chlamydial pneumonitis (cough, nasal discharge, and tachypnoea).

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Anterior segment dysgenesis

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Anterior Segment Dysgenesis

Background Anterior segment dysgenesis (ASD) describes a heterogeneous group of rare disorders characterized by variable maldevelopment of anterior segment structures including the cornea, iris, and drainage angle (Table 12.1). ASD is occasionally associated with systemic abnormalities. Glaucoma is a frequent complication and is often difficult to manage. Goniotomy or trabeculotomy may be required for infantile glaucoma; trabeculectomy with antimetabolites or drainage tubes may be required for juvenile glaucoma. A number of genes have been implicated in this group of disorders. At presentation, draw the family pedigree (p. 412), examine family members, and arrange review with an experienced clinician for genetic testing and counselling. Regularly review refraction, cornea, lens, IOP (use Tonopen if cornea involved), optic nerve, and field tests as required.

Aniridia A condition characterized by bilateral complete or partial iris hypoplasia with associated foveal hypoplasia, resulting in photophobia, reduced acuity (6/36–6/60), and nystagmus presenting in early infancy. Frequently associated ocular abnormalities, often of later onset, include cataract, glaucoma (up to 50%), and corneal opacification and vascularization (secondary to limbal stem cell deficiency). Aniridia may occur as an isolated abnormality without systemic involvement, or as part of the Wilms’ tumour–aniridia–genital anomalies–retardation (WAGR) syndrome (PAX6 and adjacent Wilms’ tumour, WT-1 locus). Aniridia may be familial or sporadic; both are caused by mutations or deletions of the PAX6 gene on 11p. Children with familial aniridia are not at significantly increased risk of Wilms’ tumour and do not need ultrasound screening. Children with sporadic aniridia should be tested for deletion of the Wilms’ tumour suppressor gene (WTS). Those with WTS deletion are at high risk of Wilms’ tumour and need regular abdominal ultrasound. Usually corneal opacification occurs in adulthood but may occur in children, necessitating limbal stem cell transplant and corneal grafting. Correct any refractive errors with tinted spectacles.

Sclerocornea Describes opaque scleral tissue with fine vascular arcades extending into the peripheral cornea. There is a spectrum of severity from complete corneal opacification to a poorly defined limbus. Most (90%) are bilateral, but often asymmetrical. It is sporadic and nonprogressive and may be associated with: cornea plana (80%); microphthalmos; iridocorneal synechiae; persistent pupillary membrane; angle and iris dysgenesis; congenital glaucoma; coloboma; posterior embryotoxon; mental deficiency; deafness; craniofacial, digital,

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Table 12.1: Anterior segment dysgenesis

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Anterior segment dysgenesis

and skin abnormalities. The differential diagnosis includes interstitial keratitis (p. 167) and arcus juvenalis.

Posterior embryotoxon Anterior displacement and enlargement of Schwalbe’s line is seen as an irregular circumferential ridge on the posterior corneal surface, just inside the limbus. Present in 10–15% of normal eyes. May be associated with primary congenital glaucoma, Alagille’s syndrome, megalocornea, aniridia, corectopia, and Noonan’s syndrome.

Axenfeld’s anomaly Posterior embryotoxon with attached iris strands. Called Axenfeld’s syndrome if glaucoma is present.

Reiger’s anomaly Axenfeld’s anomaly with hypoplasia and distortion of the iris stroma. May have corectopia or polycoria. Glaucoma occurs due to incomplete development of aqueous outflow pathways. Associated with oculodigital dysplasia, osteogenesis imperfecta and Down’s, Ehlers Danlos, Noonan’s, and Franceschetti’s syndromes. Called Reiger’s syndrome (or Axenfeld-Reiger syndrome) if there are skeletal abnormalities such as maxillary hypoplasia, abnormal dentition, micrognathia, hypertelorism, and other limb or spinal malformations.

Peter’s anomaly Congenital central corneal opacity (Fig. 12.6) with iridocorneal ± lenticulocorneal adhesions. Bilateral in 80% with glaucoma in 50–70%. Usually sporadic, but when familial, autosomal recessive inheritance is the most common.

■Type I : usually has no other abnormality.

■Type II : may have abnormal lens position, cataract, microcornea, microphthalmos, cornea plana, sclerocornea, coloboma, aniridia and dysgenesis of the angle and iris. Corneal grafting is high risk, with many cases having a poor outcome.

Posterior keratoconus May represent a mild variant of Peter’s anomaly.

Nonaccidental injury

Nonaccidental Injury

Background Ophthalmological signs of nonaccidental injury (NAI) can be varied and include periorbital and conjunctival injuries, damage to the anterior segments and lens, and vitreoretinal injuries. One of the commonest ophthalmic manifestations is retinal haemorrhage. Retinal haemorrhages are usually reported in children below 1 year of age and there is about an 80% association between subdural haemorrhage and retinal bleeding in cases of inflicted injury. Retinal haemorrhages can be caused by trauma, both accidental and nonaccidental, and nontraumatically, including infection, raised intracranial pressure, blood disorders, and rare metabolic conditions. For this reason, never assume deliberate harm has, or has not, taken place.

History and examination As legal proceedings are likely to follow, make clear, timed and dated entries in the records, including when continuing onto a new record page. Clearly record the retinal haemorrhages with drawings and photographs.

Signs The morphology of retinal haemorrhage is determined by the anatomy of the layer in which it occurred, rather than by the cause, so the appearances of retinal haemorrhages cannot be used to determine the cause of the bleeding. Although perimacular folds and traumatic retinoschisis are usually only seen in cases of inflicted injury, they have rarely been described as occurring accidentally.

Timing The timing of retinal haemorrhages is only approximate. Superficial haemorrhage normally clears in under a week; deeper intraretinal haemorrhages usually clear in 4 weeks. Preretinal and vitreous haemorrhage take longer to resolve.

Management

■Casualty : refer immediately to a consultant ophthalmologist, and designated paediatrician or nurse. They will undertake further management and contact social services if necessary. Consultant examination should occur as soon as possible and within 48 hours.

■Clinic : arrange follow-up at 1 week to review any retinal haemorrhage and again clearly describe its morphology. Review until the retinal haemorrhages clear. Some children are left significantly visually impaired from associated damage to the visual pathways, and need long-term follow-up. Electrodiagnostic testing may be useful in these children.

Reduced Vision with an

Otherwise Normal Examination

Background Reduced vision for age with an apparently normal examination may be due to ophthalmic or neurological disease. In the older child it may be functional. Some children will turn out to have subtle abnormalities on detailed examination which will identify the cause of reduced vision.

History Ask about prematurity, consanguinity, family history of ophthalmic disease, photophobia, night blindness, and evidence of field loss.

Examination Perform a full ophthalmic examination. In particular look for nystagmus, which when fine can easily be overlooked. Check for iris transillumination which will suggest albinism. Optic nerve abnormalities such as hypoplasia and atrophy can be subtle and difficult to identify; examine carefully with a direct ophthalmoscope. Check the pupil responses for an afferent defect or sluggish reactions. Small babies usually have small pupils, which may make pupil testing difficult. In older children, check colour vision. A careful examination should exclude albinism and optic nerve hypoplasia. Most retinal dystrophies have fundal abnormalities present by the time visual symptoms occur but in some cases, especially in infants, the early fundus appearance can be normal.

Investigation Perform electrodiagnostic tests if there is no obvious cause for visual loss. Consider paediatric neurological referral and neuroimaging.

Differential diagnosis Depends on the age at presentation.

■Infants

1.Cerebral visual impairment : reduced vision due to damage to the cerebral visual pathways. Most patients have associated neurological deficits. The commonest cause is hypoxic/ischaemic damage, but it may be associated with intracranial infection, bleeding or hydrocephalus. Electrodiagnostic tests show post-retinal dysfunction.

2.Delayed visual maturation (DVM) : reduced visual function in a child <16 weeks old. Vision improves with time. Three categories are recognised: visual problem only (type 1), occurring as part of a generalized developmental delay or with fits (type 2), and in association with other ocular

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Reduced vision with an otherwise normal examination

tests are normal for age. There is an increased incidence of reading problems in children who had DVM.

3.Retinal dystrophies : these may present in infancy or childhood. Most are progressive but some are stationary. They may involve either the rod or cone systems or inner retina. Nystagmus is common in early-onset forms. Electrophysiology is essential for diagnosis. There is an increased incidence of retinal dystrophies in children with high refractive errors.

4.Stationary dystrophies presenting in infancy include congenial stationary night blindness (CSNB), and the achromatopsias. Leber’s congenital amaurosis is an autosomal recessive, severe, early-onset rod–cone dystrophy. Affected infants have roving eye movements or nystagmus, high hyperopia, and poor pupillary light responses. Eye-poking is common. The initial fundus examination is usually normal but later in childhood a pigmentary retinopathy with optic disc pallor and retinal arteriolar narrowing develops. The electroretinogram (ERG) is severely abnormal or undetectable.

5.Optic nerve hypoplasia : may be unilateral or bilateral and of variable severity. The disc is very small and often appears grey. There may be a ‘double-ring sign’ with the true edge of the optic nerve being surrounded by the scleral opening which may be pigmented. There may be a history of maternal alcohol/drug ingestion. Bilateral cases may be associated with intracranial anomalies, for example septo-optic dysplasia (absence of septum pellucidum and agenesis of the corpus callosum) and pituitary stalk abnormalities. Endocrine abnormalities are common. Arrange neuroimaging and paediatric endocrinology referral.

■Children.

1.Neurological disease : whilst rare, consider neurological diseases which in the early stages may have few ophthalmological signs, including Batten’s disease and chiasmal tumours. Batten’s disease (p. 497) has an electronegative response on the photoptic ERG; chiasmal disease shows postretinal dysfunction with hemisphere asymmetry.

2.Retinal dystrophies : these include CSNB, retinitis pigmentosa, and progressive cone dystrophy. ERGs are

Optometry and general practice guidelines

Optometry and General

Practice Guidelines

If there is any doubt about the appropriate referral for a child with an eye problem, ask a pediatric ophthalmologist for advice or discuss with the local hospital eye service out of hours. The following guidelines for hospital referral urgency are not prescriptive, as clinical situations vary.

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