Long-term effects of high intensity flashes on the ERG of the rabbit

Retinal cone dysfunction of supernormal rod ERG type. Five new cases

Five patients, not related to each other, showed clinical signs, including electroretinograms, of a retinal dysfunction which mainly affected the cone system, but also involved the rod responses in a peculiar way. ERG b-wave threshold under dark adapted conditions was elevated. In contrast, rod b-wave sensitivity was enhanced with medium to high intensity flash stimulation. Furthermore, all patients had a severe reduction of the oscillatory potentials. The findings are discussed with special emphasis on a hypothetical disturbance in the cyclic guanosine monophosphate metabolism, involving both photoreceptors and cells of the inner plexiform layer responsible for retinal feedback mechanisms.