97th DOG Annual Meeting 1999
K672
ASSOCIATION OF EPILEPSY WITH VIGABATRIN CLINICAL PERIMETRY AND ELECTROPHYSIOLOGY
D. Besch, C. Asenbauer, E. Apfelstedt-Sylla, T. J. Dietrich, J. Isensee,
U. Schiefer
It is estimated that 5% of all people suffer at least one epileptic event during their lives, and that 1% of the population have the diagnosis of epilepsy established. Visual field defects have been reported in patients taking antieptiletic drugs, an association that has been pronounced in patients receiving long term therapy with Vigabatrin. Since 1989 Vigabatrin has been in world-wide use for treatment of refractory epilepsy. It produces a reduction in seizure frequency by binding irreversibly with GABA-transaminase. We report a survey of visual function changes associated with Vigabatrin and describe the typical findings for visual field testing and electrophysiology. The most striking findings include visual field constriction, especially in the nasal quadrants, a slightly decreased b-wave and attenuated oscillatory potentials during Ganzfeld electroretinography and multifocal ERG, as well as subnormal electrooculogram tracings. Damage to the retina might be the result of direct retinal toxicity caused by Vigabatrin monotherapy, or it may act only in combination with other antiepileptic drugs. The drug commission of the German medical profession recommends a baseline examination before taking Vigabatrin, followed by additional examinations during antiepileptic treatment. If any visual disturbances are discovered, detailed visual field testing and electrophysiological diagnostics should follow.
Universitäts-Augenklinik; Abteilung für Pathophysiologie des Sehens und Neuroophthalmologie; Schleichstr. 12-16; 72076 Tübingen
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