Dark adaptation in age-related maculopathy

Abstract

Dark adaptation was measured for patients with age-related maculopathy (ARM) and for age-matched controls; green and red test stimuli were flashed 15 degrees from the fovea to examine differential effects of ARM on rod and cone functions, respectively. The ARM patients showed decreases in sensitivity for both rods and cones (0.5-1.5 log units) and an increased time constant of recovery for rod function. After 20 min in the dark, sensitivity to both red and green stimuli was depressed at the fovea and at 5, 10, 15 and 25 degrees eccentric to the fovea. The greatest sensitivity loss was found in the macular area (fovea and 5 degrees eccentric). Our data suggest that the ARM patients have an abnormality in both rod- and cone-adaptation systems over a relatively large retinal area which extends beyond the zone of visual field abnormality.