Electrophysiological similarities between two eyes with X-linked recessive retinoschisis

Electroretinograms (ERG) and electro-oculograms (EOG) were studied in 88 eyes of 44 male patients with X-linked recessive retinoschisis. Differences of fundus appearance, ERG, and EOG between the eyes of each patient were analyzed. Fundus abnormalities were symmetrical in 77.3% of the cases. The amplitude of the ERG a-wave was normal in 26.1% and was abnormally low in 73.9%. The amplitude of the b-wave was below normal in all eyes; thus a small b-wave/a-wave ratio, which is characteristic of X-linked recessive retinoschisis, was observed in every case. The light peak to dark trough (LP/DT) ratio of the EOG was normal in 90.8% of the cases. The relative electrophysiological differences between the two eyes were calculated and showed that a-wave amplitude was not different between eyes in 75.0% of the cases; b-wave amplitude was not different in 77.3% of the cases; b-wave/a-wave ratio was symmetrical in 93.2% of the cases; and the LP/DT ratio was consistent between eyes in 86.8% of the cases. These results suggest that in most cases of X-linked recessive retinoschisis the fundus appearance, ERG, and EOG are similarly affected in both eyes of the patient.