Rod ERG diurnal rhythm in some patients with dominant retinitis pigmentosa.

Five patients with dominant retinitis pigmentosa who were monocularly entrained to a 14 hr light: 10 hr dark cycle showed an abnormal diurnal rhythm in the rod electroretinogram of the entrained eye. These patients as a group showed larger-than-normal reductions in b-wave sensitivity 1.5 hr and 8 hr after light onset relative to other times of day. The findings raise the possibility that these patients have an abnormality in rod photoreceptor function associated with the process of outer segment renewal.