Spatiotemporal contrast sensitivity and colour vision in multiple sclerosis.

Measures of contrast sensitivity and colour vision were taken from a group of 18 multiple sclerosis patients. Contrast sensitivity losses, measured at 5 spatial frequencies and 4 temporal frequencies, were found to be significant in 11 patients. Red/green (Rayleigh equation) and green/blue (Engelking-Trendelenburg equation) Pickford-Nicolson anomaloscope settings were abnormal in 15 patients. Correlating each of the 20 spatiotemporal losses with the colour losses revealed that in 19 conditions the red/green loss was greater than the green/blue loss. None of the green/blue losses correlated significantly with spatiotemporal losses while between 2 and 8 cycles/deg 11/12 spatiotemporal conditions showed significant correlations with red/green colour loss. These results support a locus of damage before the cortex at a stage in the visual pathway where red/green chromatic information may be encoded in pathways which also code luminance information.