Lumboperitoneal shunting as a cause of visual loss in benign intracranial hypertension.

The causes of visual loss in benign intracranial hypertension are related to long standing papilloedema, ischaemic optic neuropathy or haemorrhage into a subretinal neovascular membrane. Decompression procedures generally preserve or improve visual acuity but surgical treatment with subtemporal decompression may lead to visual impairment. Such a deficit has been recorded in the past as occurring with ventriculography. Postulated mechanisms have included brain herniation, spasm of vessels supplying the visual cortices or retinal vascular disturbance. To our knowledge treatment with lumboperitoneal shunting has not previously been reported as leading to further significant visual loss in this condition. This report describes such an occurrence in a patient. Retinal vascular disturbance is postulated on the basis of several normal CT scans, normal CSF pressure measured after surgery and visual evoked responses suggesting retinal or optic nerve damage.