Delayed rod dark adaptation in patients with Stargardt's disease.

Twelve patients with Stargardt's dystrophy were each found to have a prolongation in rod dark adaptation. All had a normal rate of recovery during the early portion of rod dark adaptation but a selective prolongation of the later segment of rod recovery. This observation was apparent in patients with limited fundus flecks and those with extensive fundus flecks, whether or not a dark choroid was observed and independent of the presence or absence of an atrophic-appearing macular lesion. A defect within retinal pigment epithelial cells of an enzyme or intracellular transport mechanism involved in the visual pigment regeneration cycle could account for these findings.