PERIPHERAL RESOLUTION USING STATIONARY AND FLICKERING GRATINGS - THE EFFECTS OF AGE

Purpose. Currently, little or no psychophysical data exist on the decl ine in retinal ganglion cell density, with age or on the nature of any selective age-related loss of one cell type over another. The authors wished to determine the nature of any decline in ganglion cell densit y with age using measurements of peripheral grating resolution, which is directly related to ganglion cell sampling density. Methods. We mea sured grating resolution at 4 different retinal locations in a group o f 97 normal subjects ranging in age from eight to eighty-one years. St imuli were either stationary or employed counterphase flicker at 30 Hz in order to selectively stimulate a greater proportion of either P or M ganglion cells. Results. Mean resolution was significantly higher f or stationary gratings than flickering gratings. Loss of peripheral re solution was approximately 5%/decade for stationary gratings and 6%/de cade for flickering gratings. The ratio of resolution for flickering/n on-flickering stimuli showed a small but insignificant decline with ag e. Conclusions. There is a general decline in peripheral resolution wi th age, indicating a corresponding loss of retinal ganglion-cell densi ty. This age-related loss does not appear to be very selective in term s of cells that are sensitive to either stationary or flickering grati ngs. These results increase the diagnostic power of clinical tests tha t employ measures of peripheral resolution in subjects of different ag es to detect diseases which cause loss of ganglion cells.