Ischaemic optic neuropathy.

Ischaemic optic neuropathy is a well recognised cause of sudden visual loss in middle and late life. It is characterised by painless visual impairment, pale swelling of the optic disc and nerve fibre bundle field defects. Although some cases are due to cranial arteritis, the majority of patients suffer from non-arteritic diseases, particularly hypertension. The present study consists of a reveiw of 22 cases of ischaemic optic neuropathy. Apart from cranial arteritis and vascular disease, migraine and trauma appear to have a causal relationship to the disorder.