Selective Colour Vision Deficits in Multiple Sclerosis at Different Temporal Stages

Abstract

Multiple sclerosis (MS) without optic neuritis causes color-vision deficit but the evidence for selective color deficits in parvocellular-Red/Green (PC-RG) and koniocellular-Blue/Yellow (KC-BY) pathways is inconclusive. We investigated selective color-vision deficits at different MS stages. Thirty-one MS and twenty normal participants were tested for achromatic, red-green and blue-yellow sinewave-gratings (0.5 and 2 cycles-per-degree (cpd)) contrast orientation discrimination threshold. Red-green mean threshold at 0.5cpd in established-MS and blue-yellow mean threshold in all MS participants were abnormal. These findings show blue-yellow versus red-green color test is useful in differentiating MS chronicity, which helps to better understand the mechanism of colour-vision involvement in MS.

Keywords: Multiple sclerosis; blue/yellow; colour vision; psychophysics; red/green.

Figure 1.

Horizontal achromatic, vertical red–green and horizontal blue–yellow sinusoidal Gabors presented to participants and controls.

Figure 2.

(a) Mean contrast threshold for achromatic stimuli at 0.5 and 2 cycles per degree SF. The difference in the mean contrast threshold of early MS, established MS and controls was not statistically significant. Error bars represent ± 0.5 standard deviation. (b) Mean contrast threshold for red–green stimuli at 0.5 and 2 cycles per degree SF. The mean contrast threshold was significantly elevated in established MS at SF of 0.5 compared with controls. Error bars represent ± 0.5 standard deviation. (c) Mean contrast threshold for blue–yellow stimuli at 0.5 and 2 cycles per degree SF. The mean contrast threshold at 2 cycles per degree was significantly higher in early and established MS versus controls. Error bars represent ± 0.5 standard deviation.