Visual function in patients treated with the GABAergic anticonvulsant drugtiagabine

Objective: To evaluate whether the anticonvulsant drug tiagabine is associa ted with changes in visual function, particularly that of visual field loss . Patients: 15 patients with chronic partial epilepsy treated for 23 to 55 mo nths with tiagabine monotherapy after failure with standard anticonvulsant drug monotherapy were investigated. Main Outcome Measures: The visual field was examined by kinetic perimetry w ith the Goldmann perimeter and by age-corrected 120 Full Field suprathresho ld static perimetry with the Humphrey Field Analyser, contrast sensitivity with the Pelli-Robson letter chart, and colour vision with the Standard Pse udo-isochromatic Plates part 2, Farnsworth-Munsell 100 Hue test and Color V ision Meter anomaloscope. Results: None of the patients treated with tiagabine monotherapy had concen tric visual field loss. Three patients had localised field loss (two quadra ntanoptic and one hemianoptic) from earlier brain lesions. Acquired colour vision defects were found in seven of 14 (50%) examined patients. Contrast sensitivity was within normal ranges. Conclusions: Long-term monotherapy with the GABAergic anticonvulsant drug, tiagabine, showed no effect on visual fields in patients with chronic parti al epilepsy. Acquired colour vision defects occurred as often as in patient s treated with other anticonvulsant drugs.