DefinitionAmaurosis 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.See: Stroke risk factors and prevention
Alternative NamesTransient monocular blindness
Causes, incidence, and risk factorsAmaurosis fugax is a symptom of carotid artery disease. The carotid arteries are on each side of your neck under the jaw. They provide the main blood supply to the brain. Amaurosis fugax occurs when a piece of plaque in one of these arteries breaks off and travels to an artery in the eye.Plaque is a hard substance that forms when fat, cholesterol, and other substances build up in the walls of arteries. Risk factors include:Alcohol abuseCocaine useDiabetesFamily history of strokeHighblood pressureHigh cholesterolIncreasing ageSmoking (people who smoke one pack a day double their risk of a stroke)
SymptomsSymptoms 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 testsTests include a complete eye and neurological exam. The doctor or nurse will also use a stethoscope to listen to the arteries in your neck. 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 see if you have a blockage in the carotid artery. Blood tests should be done to check your cholesterol and blood sugar (glucose) levels.
TreatmentTreatment of amaurosis fugax depends on the severity of the blockage in the carotid artery. The goal of treatment is to prevent a stroke.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. 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. 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 plans if you have high blood pressure, diabetes, high cholesterol, and heart disease.Your doctor may also recommend:No treatment. You may only need regular check-ups to check the health of your carotid artery.Aspirin, warfarin (Coumadin), or other blood-thinning medications to lower your risk of stroke.If a large part of the carotid artery appears blocked, carotid endarterectomy surgery is done to remove the blockage. The decision to do surgery is also based on your overall health.
Expectations (prognosis)Amaurosis fugax itself usually does not result in long-term vision loss. However, it means you have an increased risk for stroke.
Calling your health care providerCall 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.
ReferencesGoldstein LB, Bushnell CD, Adams RJ, et al. Guidelines for the primary prevention of stroke:a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2011 Feb;42(2):517-84. Epub 2010 Dec 2.