Selective loss of chromatic sensitivity in demyelinating disease.

Thresholds for detecting changes in color for isoluminant stimuli and for detecting changes in luminance were measured in patients with histories of demyelinating disease and in normal controls. Thresholds for detecting changes in color were higher for patients' affected eyes, that is, ones in which symptoms had been found previously, than in their unaffected eyes, or for eyes of control subjects. Thresholds for detecting changes in luminance were raised less than those for changes in color. The pattern of loss is different than that found in subjects with congenital color blindness. The results suggest that the impairment occurs at a level in the nervous system beyond which signals from more than one class of cone receptor are combined.