TOPOGRAPHY OF THE AGE-RELATED DECLINE IN MOTION SENSITIVITY

Purpose. We examined whether the decline in motion sensitivity in the elderly is equivalent for different visual field locations. Methods. H igh velocity (28 degrees/s) random dot kinematograms (RDK's) were used to measure direction discrimination thresholds for 5 locations in the visual field (1 position centered on fixation and 4 locations each ce ntered 18 degrees from fixation in the nasal, temporal, superior, and inferior quadrants). Differential luminance sensitivity was assessed b y automated perimetry. Younger (N = 15, mean age = 22.9 +/- 1.3 years) and older (N = 13, mean age = 66.6 +/- 4.5 years) subjects were studi ed. Results. Motion sensitivity varied with test location for both you nger and older subjects, but sensitivity was significantly lower in ol der individuals. The largest age-related reduction in sensitivity was in the central location, whereas the smallest decline was in the super ior position. No significant correlations between motion and different ial luminance sensitivity were evident. Conclusions. There is a signif icant age-related deterioration in visual sensitivity to motion which is more pronounced in the central visual field than in some regions of the more peripheral field. Although both motion and differential lumi nance sensitivity decrease with age, the rate and the magnitude of the loss differ for these two visual functions.