Bilateral homonymous hemianopia.

Bilateral homonymous hemianopia occurred in 15 patients seen during a four-year period. Persons with this visual deficit had similarly shaped visual field defects on corresponding sides of the vertical midline for each eye, equal visual acuity which is generally normal, and normal pupil and fundus examinations. The most common causes of the bilateral posterior cerebral artery insufficency were arteriosclerosis (40%), uncalherniation (20%), and migraine (13%).