AGE-RELATED EFFECTS OF GLARE ON LUMINANCE AND COLOR CONTRAST SENSITIVITY

Purpose. To determine the effect of disability glare (DG) upon luminan ce and color contrast sensitivity for young and elderly subjects. Meth ods. DG was defined as the difference in contrast sensitivity with and without the presence of a glare source. Isoluminant color gratings we re modulated either along a red-green (R-G) or blue-yellow (B-Y) axis. Results. Without glare the effect of age on sensitivity to both lumin ance and R-G color-modulated gratings was small and did not reach stat istical significance (P > 0.1). However, the reduction in sensitivity for B-Y color modulation was highly significant (P < 0.01). For both a ge groups, DG was greatest for the R-G stimulus and least for the B-Y. DG in the elderly increased relative to the young observers for both R-G and luminance-modulated gratings (P < 0.01) but not for B-Y (P > 0 .1). Conclusions. The precise effect of a glare source on color discri mination depends upon a complex interaction between the chromaticity o f the glare source and that of the stimulus. In certain circumstances, such as in our R-G stimulus, glare can dramatically reduce chromatic discrimination ability by desaturating the component colors.