Visual pigment kinetics in abnormalities of the uvea-retinal epithelium interface in man.

In four patients with abnormalities of the interface between photoreceptors and their vascular supply, bleached visual pigments regenerated abnormally slowly, with double exponential time courses, although the time constant of the first exponential was abnormally fast. During therapy in one patient the slower exponential returned to normal early after treatment, whereas the fast component persisted even after clinically complete recovery. The results could be explained by the following hypothesis. In normal eyes, two pigment-regeneration routes exist, the more rapid (which depends on a short-lived intermediate) playing no role after a long full bleach. Uvea abnormalities cause slower regeneration in the normal main route and slower breakdown of the normally short-lived intermediate.