OBJECTIVE To evaluate white sphere kinetic perimetry (WSKP) as a test of the peripheral visual field in young children with a history of epilepsy and treatment with Vigabatrin (VGB). VGB is an antiepileptic medication that is associated with visual field constriction. METHODS Thirty-one VGB patients and 10 control subjects, median age 6 years, were recruited. Visual field extent on the major oblique meridia was tested with a 6 degrees white sphere and WSKP, a method used by Quinn et al. to study field extent in children with retinopathy of prematurity. The same meridia were tested using Goldmann kinetic perimetry (GKP; 1.7 degrees target) in those who were capable. Monocular and binocular tests were conducted. Visual field extent for WSKP and GKP were compared in VGB patients and control subjects. RESULTS Twenty-eight of 31 VGB patients were testable with binocular WSKP and their median visual field extents were smaller than controls. In 8 of 28 (29%) VGB patients, binocular field extents were smaller than the minimum in the control subjects. Monocular WSKP results did not differ between VGB patients and control subjects. Nine VGB patients were testable with both WSKP and GKP; visual field extents did not differ between tests. CONCLUSIONS WSKP is feasible in VGB patients, even in those with developmental delays. WSKP has the potential to detect visual field constriction associated with VGB use.