[Luminance contrast and color contrast evoked pattern electroretinogram in normal eyes and in eyes with glaucoma]

Pattern-onset ERGs obtained with color contrast (red-green, blue-yellow) and luminance contrast (green "black") square-wave-stripe patterns (spatial frequency 0.3 c/deg, 32 degree field) were studied in larger groups of normal and glaucomatous (chronic open-angle glaucoma) eyes. Colored stimuli were generated in a two-channel Maxwellian-view system using grating monochromators. In producing isoluminant lights of different colors, the peak latency of the response was used as a criterion. Luminance-contrast responses always have significantly smaller amplitude and shorter peak latency than color-contrast responses. This can be explained by the smaller number and shorter latency of the non-color-coded phasic anglion cells and by the larger number and longer latency of the color-coded tonic cells. Glaucomatous eyes respond with significantly smaller amplitudes at all contrast conditions tested; however, this response reduction is most pronounced with red-green patterns. Peak latencies are not significantly altered in glaucomatous eyes. Since red-green patterns are most appropriate in showing glaucoma damage in the pattern ERG, the largest absolute losses seem to occur among the large red-green antagonistic group of ganglion cells.