Mark Jacobs

Ophthalmologic Assessment of Young Patients with Alport Syndrome

BACKGROUND Alport syndrome is an X-linked disease affecting basement membrane collagen. It is characterized by nephritis associated with high-tone sensorineural hearing impairment and ophthalmic signs. Although ocular changes have been described in adults, few data exist regarding the incidence of abnormal ocular features in adolescence and childhood. METHODS Fifteen male and five female patients with Alport syndrome underwent ophthalmologic, audiologic, and nephrologic assessments. All patients studied had hematuria and a positive family history of Alport syndrome. Thirteen patients had a renal biopsy that showed characteristic electron microscopic changes of the disease. Eleven patients had high-tone sensorineural impairment. Electrophysiologic investigations performed included electroretinography, visual-evoked potentials, and electro-oculography. RESULTS Two patients had early signs of anterior lenticonus, three had flecks in the retina, and two patients also had posterior subcapsular cataracts. None of the patients had significant electrophysiologic abnormalities. CONCLUSION These findings indicate that ocular changes are uncommon and subtle in young patients with Alport syndrome, and suggest that the signs increase in frequency and severity with age.

Posterior Lenticonus: Clinical Patterns and Genetics

Posterior lenticonus is an uncommon abnormality in the shape of the crystalline lens, characterized by a spheroidal or conical protuberance affecting the posterior lens surface. It may be unilateral or bilateral. A male infant with bilateral posterior lenticonus is described, whose mother was found to have bilateral sutural cataracts. The association of cataracts with posterior lenticonus and the genetics of the condition are discussed.

An electrophysiological study on children and young adults with Alport's syndrome.

Alports syndrome is characterised by progressive haematuric nephritis and high tone sensorineural hearing loss. Ocular signs are variable, the most consistent findings being anterior lenticonus and retinal flecks in the macula and mid peripheral areas. Previous electrophysiological studies on patients with Alports syndrome have mostly been on adult patients undergoing haemodialysis, or after renal transplantation. A group of young patients with Alports syndrome were studied to assess if early electrophysiological changes were detectable. A total of 20 patients (15 males and five females) between the ages of 3.5 and 22 years (mean 12.7 (years) were examined and compared with control subjects. Visual evoked potentials and electroretinograms were obtained following flash and pattern reversal stimulation. Electro-oculograms were also recorded. No significant electrophysiological changes were found in any of the 20 patients, including four who had visible fundus changes.

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.

Persistent Pupillary Membranes

Extensive persistent pupillary membranes which occlude the pupil may occur in isolation or in association with other ocular anomalies. Amblyopia may result if the membranes are extensive. We favor nonsurgical intervention except if unusual circumstances are present as demonstrated in one of our two cases.

Human ocular motor neural integrator failure

Eye movements in the light and the dark were recorded from two young patients: the first aged five years had been diagnosed with cerebral palsy secondary to perinatal hypoxia, and the second aged six years had atypical congenital idiopathic nystagmus but was otherwise healthy. In the dark sustained head rotation elicited abnormal tonic eye deviations instead of vestibular nystagmus. In both patients, some quick phases were present but they were always followed by decaying exponential drifts back to the current level of tonic deviation with time-constants of 0.34 and 0.24 s. These waveforms were very similar to those recorded from animals who have had neurotoxins injected into the region of the nucleus prepositus hypoglossi and the medial vestibular nucleus, where the brainstem neural integrator is thought to reside. In the light, the first patient had gaze-paretic nystagmus, no optokinetic nystagmus (although quick phases were present), and virtually no smooth pursuit. In marked contrast, the second patie...