Bilateral homonymous hemianopsia due to tentorial herniation, with sparing of central vision: case report.

Cases of complete bilateral homonymous hemianopsia with sparing of central vision that are caused by bilateral tentorial herniation are extremely rare. We describe one such case resulting from severe head trauma, the first to be reported in which magnetic resonance images showed clear evidence of the responsible lesion. The causes of bilateral homonymous hemianopsia with sparing of central vision and the possible mechanisms whereby macular sparing may arise are discussed.