Contrast sensitivity in age-related macular degeneration.

Low-contrast charts were used to investigate the possibility that patients with drusen have visual deficits not detected by standard Snellen charts. We compared performance on Regan letter charts between 52 eyes with drusen and Snellen acuity of 20/20 and 27 control eyes. The drusen group read fewer letters than the control group on all of the charts tested. This difference increased as the contrast of the charts decreased. The loss of performance on all of the Regan charts correlated with drusen severity. Twenty-one eyes with drusen and normal Snellen acuity also were tested with a Ginsburg contrast sensitivity chart and compared with age-matched normal controls. The results showed a loss of contrast sensitivity at high spatial frequencies and a loss of peak contrast sensitivity with increasing drusen severity. These results suggest that in patients with drusen, low-contrast charts may be useful for measuring visual loss not detected by standard Snellen charts.