Treatment of Vasospastic Amaurosis Fugax with Calcium-Channel Blockers

Abstract

Amaurosis fugax, a brief loss of vision in one eye, is caused by hypoperfusion of the retinal circulation. If an attack of amaurosis is prolonged, the patient is at risk of permanent visual loss. Since the 1950s, amaurosis fugax has usually been attributed to embolism from the heart or great vessels¹ or to carotid occlusive disease. Because of the difficulty in differentiating between these and other causes, amaurosis fugax remains a therapeutic challenge. Depending on the patency of the internal carotid arteries, the principal treatments are anticoagulation or antiplatelet therapy² and carotid endarterectomy³. Vasospasm is rarely reported as a cause of this clinical problem⁴. Nevertheless, Winterkorn and Teman⁵ have reported the successful treatment of amaurosis fugax in a man with recurrent vasospasm of the ophthalmic artery. Extensive evaluation revealed neither an embolic source nor decreased carotid blood flow. Examination during one 12-minute period of visual loss revealed that the retinal arterioles were constricted. Despite daily aspirin therapy, the patient had up to a dozen episodes of monocular blindness each day for several months. The attacks ceased within a day after the patient started treatment with nifedipine. Since this initial case report, we have successfully used calcium-channel blockers to treat selected patients with recurrent amaurosis fugax.