Visual Field Defect in the Vigabatrin-treated Pediatric Patients

Kim, Joon Sik; Lee, Sang Lak

Abstract

PURPOSE: Vigabatrin has proved to be a successful and well tolerated drug used for the treatment of epilepsy of partial onset and for infantile spasms(West's syndrome). It is a selective and irreversible inhibitor of gamma-aminobutyric acid transaminase that is associated with visual field defect. We performed this study to investigate visual field defects in children treated with Vigabatrin.
METHODS
We performed a complete neuroophthalmologic examination and electrophy siologic studies on 28 patients receiving Vigabtrin. They underwent static perimetry using either full field 81 points or central 30-2 threshold screening program on the Humphrey visual field analyser, followed by the ophthalmic examination to rule out ocular causes for visual field defects.
RESULTS
The patients had a mean age of 11.9+/-3.1 years and the mean treatment duration with Vigabatrin was 14.9 months. 11 of 28 patients were abnormal on static perimetry. Among them, four were false negative, one was false positive and two had fixation loss, which were suggestive of poor cooperation. Four of them had visual field defects including right homonymous inferior quadrantanopia, left incongruous incomplete hemianopsia, bilateral right homonymous hemianopsia, bilateral left homonymous hemianopsia.
CONCLUSION
Visual field examination in children is more difficult than in adults because of a lack of cooperation. Although we could not find any patients with visual field defect from Vigabatrin, vigilance and close follow up are necessary when the drug is prescribed.