We evaluated retrospectively the clinical records and electrophysiological results of 52 patients suffering from X-linked congenital retinoschisis. Characteristic clinical findings were hyperopia (mean +2.3 +/- 3.1 D), reduced visual acuity (mean 0.24 +/- 0.2) and always macular pathology. Peripheral retinoschisis was present in 53% of the eyes. The natural course of the disease was normally stable. Complications were visual loss in 9.3%, vitreous hemorrhages in 4.7% and retinal detachments in 10.7% of the eyes. These complications generally occurred within the first decennium. Prophylactic laser coagulation was of no use because it was complicated by retinal detachment in 43% of our series. The electrooculogram was usually normal. In addition to the known electroretinographic findings of a low normal a-wave and reduced b-wave amplitudes, we found prolonged b-wave latencies and implicit times.