Homonymous Quadrantanopia Caused by Occipital Lobe Ulegyria

Purpose: We report a case of homonymous quadrantanopia caused by occipital lobe ulegyria. Case summary: A 23-year-female was referred to our clinic because of a visual field defect incidentally discovered during preoperative evaluation for refractive surgery at another clinic. However, she did not report any symptoms. She had no systemic diseases. Visual acuity was 20/20 in both eyes, and the color vision test was normal. Both pupils exhibited normal responses to light and near stimulations. In fundus examinations, the right optic disc was normal and the left contained drusen. Automated perimetry revealed right lower homonymous quadrantanopia with macular sparing. Brain magnetic resonance imaging revealed areas of ulegyria involving the left occipital lobe, consistent with the visual field defect. A follow-up visual field test performed 5 months later yielded the same result. Conclusions: Neuroimaging should be performed in patients with homonymous visual field defects to determine the location and etiology of the brain lesions. Occipital lobe ulegyria can cause homonymous quadrantanopia in the absence of any neurological problem.