Sector retinitis pigmentosa. Electrophysiological and psychophysical study of the visual system.

Combined clinical, psychophysical and electrophysiological examinations of the visual function were performed in two patients affected by sector retinitis pigmentosa. Psychophysical dark adaptation measurements, the electroretinogram (ERG) and the electro-oculogram (EOG) revealed that a larger area of the neural retina and pigment epithelium were pathologically involved than revealed by ophthalmoscopy and visual field. Five years of observation showed a stationary retinal defect in one patient, while in the other a slight clinical but a marked electroretinographical deterioration was found over a period of twelve years. However, visual acuity and the visually evoked potential (VEP) remained normal. In spite of subnormal ERG amplitudes, the photopic and scotopic peak latencies were normal in both cases. In the ophthalmoscopically normal relatives of one patient slight dark adaptation impairments, as well as EOG and ERG disturbances, were detected.