Pattern reversal visual evoked potentials following early treatment of unilateral, congenital cataract.

OBJECTIVE

To describe the pattern reversal visual evoked potentials (VEPs) that were used to monitor and quantify early visual development following treatment for dense, unilateral, congenital cataract.

DESIGN

Longitudinal prospective study.

PATIENTS: Six infants who underwent surgery and contact lens correction before age 5 months and who had good compliance with occlusion therapy throughout the first 3 years of life.

RESULTS

Initially, VEPs from aphakic eyes showed marked abnormalities, including small amplitudes, prolonged latencies, missing components, and absent VEPs to small check sizes. Threshold check size was elevated by 3 octaves or more. With part-time occlusion of the opposite eye, VEPs normalized rapidly in the first year, but residual deficits remained to age 4 years when visual acuities were between 20/50 and 20/120 in aphakic eyes. Threshold check size clearly differentiated between aphakic and normal eyes and was the only VEP parameter that was correlated with single-letter visual acuity. Thus, threshold check size had greater clinical use than measures of pattern VEPs based on latency, amplitude, or waveform.

CONCLUSIONS

Patients treated for unilateral congenital cataract, who have early surgery and contact lens correction and comply with occlusion therapy, show a period of rapid VEP maturation and have a good visual prognosis.