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
Causes, incidence, and risk factors
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.
Signs and tests
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:
- No treatment. You may only need regular check-ups to check the health of your carotid artery.
- Diet changes and medication to help lower your cholesterol and control your blood pressure.
- Aspirin, warfarin (Coumadin), or other blood-thinning medications to lower your risk of stroke.
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.
Calling your health care provider
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:
- Avoid fatty foods. Follow a healthy, low-fat diet.
- Do not drink more than 1 to 2 alcoholic drinks a day.
- Exercise regularly: 30 minutes a day if you are not overweight; 60 - 90 minutes a day if you are overweight.
- Quit smoking.
- Get your blood pressure checked every 1 - 2 years, especially if high blood pressure runs in your family. If you have high blood pressure, heart disease, or have had stroke, you need to have it checked more often. Ask your doctor.
- Most people should aim for a blood pressure below 120-130/80 mmHg. If you have diabetes or have had a stroke, your doctor may tell you to aim for a lower blood pressure.
- Adults should have their cholesterol checked every 5 years and treated, if needed. If you have been treated for high cholesterol, you will need it checked more often.
- If you have diabetes, heart disease, or hardening of the arteries, your LDL "bad" cholesterol should be lower than 70 mg/dL.
- Follow your doctor's treatment recommendations if you have high blood pressure, diabetes, high cholesterol, and heart disease.
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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.
Reviewed By: Daniel Kantor, MD, Medical Director of Neurologique, Ponte Vedra, FL and President of the Florida Society of Neurology (FSN). Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.