Multiple evanescent white dot syndrome. II. Electrophysiology of the photoreceptors during retinal pigment epithelial disease
P. A. Sieving, G. A. Fishman, L. M. Jampol and D. Pugh
We performed electrophysiologic studies of photoreceptor function in three
patients with multiple evanescent white dot syndrome. During the acute
stage, while the visual acuity was impaired, the electroretinogram (ERG)
a-wave and the early receptor potential (ERP) amplitudes were profoundly
decreased. The ERP regeneration times, determined for one subject, were
prolonged. These findings suggest that photoreceptor function was impaired
(abnormal a-wave), the effective visual pigment optical density of the
outer segments was markedly reduced (ERP amplitude), and visual pigment
regeneration was abnormal (ERP regeneration kinetics). During the recovery
stage, the ERG and ERP amplitudes and visual acuity returned to normal. Our
patients' disease seemed to be primarily of the retinal pigment epithelium
(RPE). The decreased visual pigment density and prolonged regeneration
kinetics emphasize the physiologic dependence of the sensory retina on the
RPE.
