Chromatic, spatial, and temporal losses of sensitivity in multiple sclerosis

Chromatic, spatial, and temporal losses of sensitivity were measured in 15 eyes of 10 patients with recovered optic neuritis. Chromatic sensitivities (for both red-green and blue-yellow) were measured using color-mixture thresholds; the chromatic sensitivity loss was classified as "selective" if it was significantly greater than the achromatic loss. Spatial and temporal sensitivities were measured with contrast sensitivity functions and flicker modulation sensitivity, respectively; these losses were classified as selective if the losses at high (spatial or temporal) frequencies were significantly greater (or significantly less) than losses at low frequencies. All patients had central fixation and were optically corrected carefully. In 1 eye, selective losses of sensitivity for red-green and blue-yellow were combined with a selective loss of sensitivity at high spatial (but not temporal) frequencies. This type of loss may indicate a selective loss of small axons in the optic nerve. The 8 other eyes that showed significant losses were generally nonselective in their chromatic, spatial, and temporal losses; this may indicate a nonselective loss of small and large axons.