Color Vision Deficits in Multiple Sclerosis

Color vision deficits have been reported in multiple sclerosis (MS) in the absence of optic neuritis (ON). Demyelination of the optic nerve in ON probably causes color-vision deficits by affecting the parvocellular-Red/Green (PC/RG) and koniocellular-Bue/Yellow (KC/BY) pathways. The evidence for selective deficits in PC/RG versus KC/BY pathways, however, is inconclusive. Moreover, the mechanism of color vision deficit in MS without ON demyelination is unclear. In this study we investigate color vision deficits in early versus late MS in the PC/RG versus KC/BY pathways.