A 51-year-old man was referred by his optometrist for an incidental finding of a visual field defect. Humphrey 24-2 SITA-Fast visual field testing revealed a left superior homonymous quadrantanopia, and magnetic resonance imaging of the brain showed a 2.0 × 0.5-cm oblong-shaped cerebrospinal fluid space posterior to the right basal ganglia. This space coursed close to the lateral geniculate body and was thought to represent a giant perivascular (Virchow-Robin) space. This case demonstrates that patients with a visual field defect without other neurological symptoms could be a result of an enlarged Virchow-Robin space along the visual pathway.