Diplopia and visual impairment as presenting symptoms of shunt failure in association with tonsillar herniation in idiopathic intracranial hypertension.

Two cases of cerebellar tonsilar herniation due to shunt complications in idiopathic intracranial hypertension are reported in which both patients presented with visual symptoms. One patient had horizontal diplopia due to an acute sixth nerve palsy along with severe constriction of visual fields while the second patient had symptoms of blurred vision. Both patients required neurosurgery, one patient requiring surgery for tonsillar descent and revision of an over-draining lumbar peritoneal shunt and the second patient only requiring revision of his over-draining lumbar peritoneal shunt. Following surgery the visual signs of reduced vision, cranial nerve palsy, and visual field loss gradually resolved. Both patients had normal ocular movements and visual fields at final follow-up.