There is evidence to show that the optic nerve and retina are affected in multiple sclerosis (MS) even without any clinical evidence or history of optic neuritis (ON). MS without optic neuritis causes colour-vision deficit, however, the evidence for selective colour deficits in parvocellular-red / green and konicellular-blue / yellow pathways is inconclusive. This study investigated selective colour vision deficits at different stages of MS progression. The cohort consisted of 31 participants with a diagnosis of MS and 20 normal controls. All participants were tested for achromatic, red-green and blue-yellow sinewave-gratings (0.5 and 2 cycles per degree (cpd)) contrast orientation discrimination threshold. Results showed that red-green mean threshold at 0.5cpd in established MS and blue-yellow mean threshold in all MS participants were abnormal. The authors conclude that their results show that blue-yellow versus red-green colour test is useful in differentiating MS chronicity, which helps to better understand the mechanism of colour-vision involvement in MS.