D Taylor

Nystagmus in infancy.

Spontaneous nystagmus in infants may be present at birth but more frequently appears in the first 6 months. We present a classification in which nystagmus with an onset before 6 months is called early onset nystagmus (EON) and is divided into three categories: sensory defect nystagmus (SDN) in which there is a proven sensory impairment, congenital idiopathic nystagmus (CIN) (sometimes called motor nystagmus2) in which no visual or neurological impairment can be found, and neurological nystagmus (NN) which is associated with neurological disease. Though the distinction between SDN and CIN is made by many authors,36 they are sometimes collectively called congenital nystagmus. The presentation of all types ofnystagmus can be similar, but in infants it is important to differentiate between SDN and CIN because of the different underlying defects, investigation, management, and genetic counselling (Fig 1).

Modulation of amblyopia therapy following early surgery for unilateral congenital cataracts.

BACKGROUND--Stimulus deprivation amblyopia is the principal cause of visual impairment in infants with unilateral congenital cataract. Even if lensectomy is undertaken at an early age, intensive postoperative occlusion of the phakic eye is essential for the development of useful vision in the aphakic eye. Despite this, the optimum method of regulating occlusion therapy is uncertain. METHODS--Interocular acuity differences identified using clinical preferential looking techniques (Keeler cards) were used to regulate target levels of phakic eye occlusion in a prospective evaluation of 10 systemically, metabolically, and neurologically normal infants in whom dense unilateral cataract was diagnosed before 8 weeks of age, and operated upon by 10 weeks. Actual occlusion levels were recorded each day by parents in a diary. The development of preferential looking acuity in the phakic and aphakic eye were compared with prediction intervals derived from observations on 43 normal children. RESULTS--Aphakic eye preferential looking acuities were within the normal range at last review in all but one infant. Interocular acuity differences were < or = 0.5 octave in all children older than 1 year of age at last review, and > or = 1 octave in three of four children less than 1 year old at last review (Fisher exact p = 0.033). Phakic eye acuities were within the normal range in all infants at all visits. CONCLUSION--Within the first 2 years of life, normal preferential looking acuity may be achieved in both eyes of infants undergoing early surgery for unilateral congenital cataract if occlusion therapy is modulated according to interocular acuity differences quantified by clinical preferential looking techniques.

Intermittent horizontal saccade failure ('ocular motor apraxia') in children.

BACKGROUND: Ocular motor apraxia (OMA) in childhood is a poorly understood condition involving a failure of horizontal saccades. OMA is thought to be rare but the literature indicates wide clinical associations. OMA is often identified by abnormal head movements, but failure of reflexive quick phases has been reported in all but a few patients. The extent of this oculomotor disorder was examined in a large group of children with diverse clinical backgrounds. METHODS: The degree of quick phase failure during horizontal vestibular and optokinetic nystagmus was measured using DC electro-oculography and video in 74 affected children, aged 17 days to 14 years. RESULTS: All children showed an intermittent failure of nystagmic quick phases, except for total failure in one case. Other visuomotor abnormalities were common including saccadic hypometria (85%), low gain smooth pursuit (70%), neurological nystagmus (28%), strabismus (22%), and vertical abnormalities (11%). Non-ocular abnormalities were common including infantile hypotonia (61%), motor delay (77%), and speech delay (87%). There was a wide range of clinical associations including agenesis of the corpus callosum, Joubert syndrome, Dandy-Walker malformation, microcephaly, hydrocephalus, vermis hypoplasia, porencephalic cyst, megalocephaly, Krabbe leucodystrophy, Pelizaeus Merzbacher disease, infantile Gaucher disease, GM1 gangliosidosis, infantile Refsums disease, propionic acidaemia, ataxia telangiectasia, Bardet-Biedl syndrome, vermis astrocytoma, vermis cyst, carotid fibromuscular hypoplasia, Cornelia de Lange syndrome, and microphthalmos. Perinatal and postnatal problems were found in 15% including perinatal hypoxia, meningitis, periventricular leucomalacia, athetoid cerebral palsy, perinatal septicaemia and anaemia, herpes encephalitis, and epilepsy. Only 27% were idiopathic. CONCLUSION: Quick phase failure is a constant feature of OMA, whereas abnormal head movements were detected in only about half, depending on the underlying diagnosis. This oculomotor sign is better described as an intermittent saccade failure rather than as a true apraxia. It indicates central nervous system involvement, has wide clinical associations, but it is not a diagnosis.

Aspects of Albinism

Genetic, clinical and electrophysiological aspects of albinism are described. Emphasis is placed on electrophysiological features which help to distinguish albinism from other clinical conditions, and on stimulating and recording factors which can affect the clarity of VEP results.

Early treatment of juvenile xanthogranuloma of the iris with subconjunctival steroids.

Five infants with biopsy proved juvenile xanthogranuloma of the iris were reviewed. Early treatment with subconjunctival injection of steroids and topical steroid drops resulted in regression of the lesion in four patients. One patient, reviewed at the age of 8 months after glaucoma which had developed secondary to the iris xanthogranuloma, had been treated by surgery alone: the visual outcome was very poor.

The use of video in assessing and illustrating abnormal eye movements in young children

Eye movement studies can be useful in neuro-ophthalmological investigations of infants and young children. In our laboratory we use a combination of an electro-oculogram and video to record eye movements. A composite video image is created consisting of an image of the electro-oculographic eye movement trace superimposed on an image of the patients eyes and face. This permits the qualitative clinical appearance of the case to be illustrated simultaneously with the quantitative eye movement trace.

Eye movement tics.

An 8-year-old girl presented with opsoclonus-like eye movement and an 18 month history of intermittent facial tics. Investigations were all normal. Electro-oculography showed the eye movements to be of variable amplitude (10-40 degrees), with no intersaccadic interval, and with a frequency of 3-4 Hz. Saccades, smooth pursuit, optokinetic, and vestibular reflexes were all normal. These abnormal eye movements eventually disappeared. It is thought that they were a form of ocular tics.

Visual evoked potentials in dissociated vertical deviation: a reappraisal

Pattern reversal and flash evoked potentials were recorded in 13 children with dissociated vertical deviation (DVD). No electrophysiological evidence was found to support the notion that patients with DVD have an anomalous (albinoid) projection of visual fibres originating from the temporal retina of each eye. However, DVD patients had significantly smaller monocular and binocular pattern evoked responses than age matched controls. Explanations are given for this finding and for the occipital VEP asymmetries reported by other workers.

Gaze evoked amaurosis in neurofibromatosis type II

Editor,—The electroretinogram (ERG) and visual evoked potential (VEP) to pattern reversal stimulation became degraded in association with visual loss in a young patient with gaze evoked amaurosis who had a mass at the apex of the left orbit. His visual symptoms improved following left orbital decompression and Snellen acuity was maintained at 6/6; however, the pattern VEP was attenuated and degraded compared with before surgery.nn### CASE REPORTnnA 9 year old boy with neurofibromatosis type II initially presented with a history of intermittent visual disturbance affecting the left eye when in left gaze. The right eye had a retinal hamartoma and a visual acuity of 6/12. He had undergone previous surgery to correct a right divergent squint. A partial third nerve palsy on the left side was present.nnOn examination, visual acuity of the left eye was 6/6 when viewing in the primary position, and pupillary reactions were normal. However, acuity became perception of light on sustained left lateral gaze, and a mild relative afferent pupillary defect became detectable at …

Cataracts in children with uveitis.

Kanski, who has contributed significantly to the management of children with uveitis, now focuses on their complicated cataracts, giving his authoritative views in this issue of B7O. The frequency of uveitis in children is relatively low, approximately 8% of all cases of uveitis occurring in children under the age of 16. Large series of patients with uveitis have been described by Kimura and Hogan,2 by Perkins,3 and by Jutte et al.4 In children, juvenile rheumatoid arthritis (JRA), also known as Stills disease, is the most common systemic association of chronic uveitis. Of340 cases of systemic uveitis in childhood Kanski and Shun-Shin found that 277 cases were associated with JRA. Juvenile ankylosing spondylitis (46 patients), juvenile psoriatic arthritis (nine patients), sarcoidosis (three patients), tuberculosis, Reiters syndrome (one patient) and the Voght-Koyanagi-Harada syndrome (one patient) were the other underlying systemic disorders. Specific uveitis entities unassociated with a systemic disorder include pars planitis, Fuchs heterochromic cyclitis, and juvenile chronic iridocyclitis. In chronic anterior uveitis the anterior chamber reaction is often not gross but can persist for years. In most cases the onset is insidious and the disease is only discovered when the child is noted to have a difference in colour between the two eyes, a difference in the shape of the pupil, the onset of strabismus, or a white mark on the pupil or the cornea. Some are detected when being examined routinely after the diagnosis of arthritis is made.7 Seventy per cent are bilaterally affected and 75% of the patients with JRA and uveitis are girls.8 Chronic uveitis in children often results in band keratopathy, cataracts, vitreous opacities, macular oedema and pucker, and glaucoma which, alone or in concert, progressively and insidiously impair vision. Before starting treatment an underlying disorder should be excluded. It is preferable not to start systemic steroids before any immunological investigations are undertaken especially where tuberculosis and sarcoidosis may be suspected. Steroids are still the mainstay of the management of uveitis. Though the chronic anterior uveitis can persist for many years in most cases it can be at least partly controlled by topical, periocular, or systemic steroids. Mydriatics may prevent but will rarely break down the posterior synechiae. It is usually best to give short acting mydriatic drops; they can, especially before synechiae have formed, be used at night causing fewer problems from the cycloplegia and mydriasis. The severe side effects of prolonged systemic steroids have often been the reason for using cytotoxic drugs in particularly severe cases of uveitis in adults: Dinning9 however felt they should not be used in children. Martenet on the other hand