Amaurosis fugax is loss of vision in one eye due to a temporary lack of blood flow to the retina. It may be a sign of an impending stroke.
Transient monocular blindness
Amaurosis fugax is a symptom of carotid artery disease. It occurs when a piece of plaque in a carotid artery breaks off and travels to the retinal artery in the eye. The carotid arteries provide the main blood supply to the brain. They are located on each side of your neck under the jaw.
Plaque is a hard substance that forms when fat, cholesterol, and other substances build up in the walls of arteries. Pieces of plaque can block blood flow. In people with amaurosis fugax, vision loss continues as long as the blood supply to the retinal artery is blocked.
Atherosclerosis of the arteries in the neck is the main risk factor for this condition. Risk factors for atherosclerosis include heart disease, high cholesterol, smoking, diabetes, and high blood pressure.
Symptoms include the sudden loss of vision in one eye. This usually only lasts seconds but may last several minutes. Some patients describe the loss of vision as a gray or black shade coming down over their eye.
Tests include a complete eye and neurological exam. In some cases, an eye exam will reveal a bright spot where the clot is blocking the retinal artery. A carotid ultrasound or magnetic resonance angiography (MRA) scan should be done to evaluate a blockage in the carotid artery.
Routine blood tests such as cholesterol and blood sugar (glucose) should be done to check your risk for atherosclerosis, which increases with high cholesterol and diabetes.
Treatment of amaurosis fugax depends on the severity of the blockage in the carotid artery. The goal of treatment is to prevent a stroke.
Your doctor may recommend:
If a large part of the carotid artery appears blocked, surgery is done to remove the blockage. The decision to do surgery is also based on your overall health. See: Carotid endarterectomy
Amaurosis fugax itself usually does not result in permanent disability. However, it means you have atherosclerosis and an increased risk for stroke.
Call your health care provider if any loss of vision occurs. If symptoms last for longer than a few minutes, or if there are any other symptoms accompanying the visual loss, it is important to seek immediate medical attention.
The following can help prevent a stroke:
Zivin JA. Hemorrhagic cerebrovascular disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 432.
Goldstein LB. Prevention and management of stroke. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 58.
Adams RJ, Albers G, Alberts MJ, Benavente O, Furie K, Goldstein LB, et al. Update to the AHA/ASA recommendations for the prevention of stroke in patients with stroke and transient ischemic attack. Stroke. 2008 May;39(5):1647-52. Epub 2008 Mar 5.