BACKGROUND: Multiple sclerosis (MS) is a disease of young and middle aged 
individuals with a demyelinative axonal damage nature in central nervous system 
that causes various signs and symptoms. As color vision needs normal function of 
optic nerve and macula, it is proposed that MS can alter it via influencing 
optic nerve. In this survey, we evaluated color vision abnormalities and its 
relationship with history of optic neuritis and abnormal visual evoked 
potentials (VEPs) among MS patients.
MATERIALS AND METHODS: The case group was included of clinically definitive MS 
patients and the same number of normal population was enrolled as the control 
group. Color vision of all the participants was evaluated by Ishihara test and 
then visual evoked potential (VEPs) and history of optic neuritis (ON) was 
assessed among them. Then, frequency of color blindness was compared between the 
case and the control group. Finally, color blinded patients were compared to 
those with the history of ON and abnormal VEPs.
RESULTS: 63 MS patients and the same number of normal populations were enrolled 
in this study. 12 patients had color blindness based on the Ishihara test; only 
3 of them were among the control group, which showed a significant different 
between the two groups (P = 0.013). There was a significant relationship between 
the color blindness and abnormal VEP (R = 0.53, P = 0.023) but not for the color 
blindness and ON (P = 0.67).
CONCLUSIONS: This study demonstrates a significant correlation between color 
blindness and multiple sclerosis including ones with abnormal prolonged VEP 
latencies. Therefore, in individuals with acquired color vision impairment, an 
evaluation for potentially serious underlying diseases like MS is essential.