Amaurosis fugax occurs when a blood clot or a piece of plaque blocks an artery in the eye. The blood clot or plaque usually travels from a larger artery, such as the carotid artery in the neck or an artery in the heart, 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:
Heart disease, especially irregular heartbeat
Family history of stroke
High blood pressure
Smoking (people who smoke one pack a day double their risk of a stroke)
Symptoms include the sudden loss of vision in one eye. This usually lasts for a few seconds to several minutes. Afterwards, vision returns to normal. Some patients describe the loss of vision as a gray or black shade coming down over their eye.
If the blockage continues, vision loss may be followed by more serious nervous system symptoms. These symptoms can be similar to those of a stroke, including weakness or speech problems.
Exams and Tests
Tests include a complete eye and nervous system exam. The doctor or nurse will also use a stethoscope to listen to the carotid 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.
Tests will be done to see if your heart is pumping blood normally or if there is a blood clot in your heart. Your heart will be monitored with an electrocardiogram (ECG) to make sure your heart rhythm is regular.
Treatment of amaurosis fugax depends on its cause. The goal of treatment is to prevent a stroke.
The following can help prevent a stroke:
Avoid fatty foods and 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.
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, or heart disease.
Your doctor may also recommend:
No treatment. You may only need regular visits to check the health of your heart and carotid arteries.
Aspirin, warfarin (Coumadin), or other blood-thinning drugs 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.
Amaurosis fugax increases your risk of stroke.
When to Contact a Medical Professional
Call your health care provider if any vision loss occurs. If symptoms last longer than a few minutes or if there are other symptoms with the vision loss, seek medical attention right away.
Goldstein 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;42:517-584.
Joseph V. Campellone, MD, Department of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.