The effect of carbamazepine, phenytoin and valproic acid anti-epileptic convulsive drugs on visual perception

We investigated the influence of the anti-epileptic drugs carbamazepine (CBZ), phenytoin (PHT) and valproic acid (VPA) on hue perception using the FM 100-hue colour arrangement test and a monitor system generating 24 different gaussian dots and by measuring transient tritanopia. All three drugs significantly altered the error score in the FM 100-hue test. Phenytoin (PHT) produced most errors in the FM 100-hue test, the largest threshold increase for perception of the gaussian dots and an elevated transient tritanopia, at least for the higher adaptation levels. Valproic acid (VPA) also elevated gaussian thresholds, especially for coloured and large stimuli, as well as affecting transient tritanopia.