[Vigabatrin and alterations of the visual field]

Since 1997 when Ecke et al described peripheral constriction of the visual field in three patients taking vigabatrin (VGB), and persistence of the changes after the drug was stopped, study of the visual fields of persons taking this antiepileptic drug has increased.

To evaluate the ocular repercussions of monotherapy with carbamazepine (CBZ), valproate (VPA) and VGB in children with epilepsy.

We made a blind retrospective study to evaluate visual side effects using Goldmann's campimetry and direct ophthalmoscopy in 9 children treated for 2.1 years with CBZ, 12 children treated with VPA for 3.1 years and 12 children treated for 2.1 years with VGB, all as monotherapy. In recent years visual evoked potentials (VEP) have also been assessed before starting treatment and every six months during treatment.

One child treated with CBZ had changes in vision (blurred vision which disappeared on reducing the dose), 3 treated with VGB (diplopia which disappeared spontaneously in 2 and after reducing the dose in 1) and none of the group treated with VPA had these symptoms. All the campimetry done was found to be normal. Two of the 12 children treated with VGB had reduction in the amplitude of VEP, which became normal later.

Since the changes in vision caused by VGB seem to be irreversible and asymptomatic in most cases, campimetric study is advisable in patients taking VGB, both when starting treatment and whilst this is being continued.