The prevalence, risk factors, and long-term outcome of vigabatrin-associated visual field defects were examined in 60 adult patients with partial epilepsy treated with vigabatrin for 7 months to 14 years at the University of Kuopio Hospital, Finland. At first examination, bilateral concentric defects occurred in 24 (40%) of 60 patients; they were severe in 8 (13%), and a mild constriction in 16 (27%). Repeated kinetic Goldmann perimetries and follow-up examination performed after 4 to 38 months (mean, 15 mos) in 55 patients (29 having discontinued therapy) revealed no reversion or progression in visual field constriction. [1]

COMMENT. The age of the patients and high cumulative doses of vigabatrin employed could be risk factors for the poor outcome and severe limiting effect on daily activities in adults. In a young patient, recovery of visual fields has been reported after early withdrawal of vigabatrin [2]. Duration of vigabatrin treatment (but not the dose or age of child) was correlated with visual field constriction in 65% of 17 children examined by perimetry at Shaare Zedek Medical Center, Jerusalem (Gross-Tsur V et al. 2000, reviewed in Ped Neur Briefs July 2000;14:49). VEPs and ERGs can be useful indicators of visual function in young or retarded patients when perimetry is inappropriate. Unless the effect on visual fields can be prevented, this significant risk seems to outweigh the benefits of using vigabatrin for the treatment of infantile spasms.