Assessment of colour vision in epileptic patients exposed to single-drug therapy

Diploma, blurred vision and colour disturbances are well-known side effects associated with anti-epileptic drugs (AEDs). Farnsworth-Munsell 100-hue co lour test (F-100) is an accepted and sensitive tool to: detect changes in c olour perception. To determine tl-ie impact of AEDs upon colour vision, we evaluated 37 consecutive patients with complex partial seizures exposed to monotherapy with phenytoin (PHT), carbamazepine (CBZ) or valproic acid (VPA ). All had normal IQ and no congenital disturbances in colour vision or ocu lar diseases. Twenty normal controls were used for statistical analysis. Th irteen patients were exposed to PI-IT, 12 to CBZ and 12 to VPA. Visual colo ur perception was impaired in 30/37 (82%) of the study group. The most sign ificant abnormality was detected in the blue-yellow axis in 10/13 patients exposed to PHT (p < 0.02) and in 8/12 treated with CBZ (p < 0.009). In 8/12 patients taking VPA, no significant abnormality was observed (p < 0.06). N one of the studied patients complained of colour vision disturbances. Our f indings strongly support the negative effect of AEDs upon colour vision dis crimination, most likely due to changes at the retinal processing level. F- 100 proved to be very useful to assess early toxicity due to AEDs.