Preventable blindness in giant cell arteritis.

Giant cell arteritis is an important cause of blindness in the elderly. Often vision may be lost because of a delay in diagnosis. The commonest ophthalmic presentation is anterior ischaemic optic neuropathy with optic disc pallor and swelling; also recognised are diptopia, occlusion of the central retinal artery, and amaurosis fugax.' These, in the presence of an increased erythrocyte sedimentation rate or plasma viscosity, require prompt steroid treatment. We report on two patients with unusual presentations in whom the diagnosis of giant cell arteritis was delayed, resulting in blindness.