Visual abnormalities vigabatrin

In a double-bUnd, randomized study in patients with partial epilepsy three of 32 patients taking vigabatrin had abnormal visual perimetry after the end of the study (36). 

Manuchehri K, Goodman S, Siviter L, Nightingale S. A controlled study of vigabatrin and visual abnormalities. Br J Ophthalmol 2000 84(5) 499-505. 

In a randomized monotherapy trial in newly diagnosed epilepsy, seven of 32 patients who were stiU taking vigabatrin after 3-9 years had concentrically constricted visual fields, and the defect was rated as severe in two (35). Of the seven patients with field defects, five had reduced oscillatory potentials and two also had abnormal a and b waves in rod and cone electroretinography. In contrast, none of the 20 patients who were stiU taking carba-mazepine had abnormal visual fields. There is also preliminary evidence that a pre-existing visual field defect increases susceptibility to vigabatrin-induced visual field constriction. 

There was abnormal color perception in 32% of 32 patients taking vigabatrin monotherapy in four cases there was an abnormality in the blue-yellow axis (64). In the same patients there was a positive correlation between visual contrast sensitivity and the size of the visual field macular photo-stress and glare tests were equal in both groups and did not differ from normal values there was no effect on glare sensitivity (65). 

In 204 patients with epilepsy, grouped on the basis of antiepileptic drug therapy (current, previous, or no exposure to vigabatrin), there was bilateral visual field constriction in 59% of current users, 43% of prior users, and 24% of never users [426 ]. Assessment of retinal function showed abnormal responses in 48% of current users and 22% of prior users, but in none of the never users. 

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