Postural vision loss in giant cell arteritis.

Two patients with biopsy-proven giant cell arteritis experienced bilateral transient vision loss after bending over and after getting up from a supine position. One patient had no demonstrable signs of carotid, ophthalmic, or anterior ciliary vascular disease, suggesting that his episodes of transient vision loss were due to vertebrobasilar insufficiency. The other patient experienced bilateral postural vision loss in the context of impending bilateral anterior ischemic optic neuropathy. Bilateral transient postural vision loss is an uncommon manifestation of giant cell arteritis that could reflect either severe bilateral vascular compromise of the anterior circulation or severe vertebrobasilar insufficiency. In either situation, prompt evaluation and treatment is indicated to prevent the irreversible sequelae of the disease.