Amaurosis fugax
Transient monocular blindness; Transient monocular visual loss; TMVL; Transient monocular visual loss; Transient binocular visual loss; TBVL; Temporary visual loss - amaurosis fugaxAmaurosis fugax is a temporary loss of vision in one or both eyes due to a lack of blood flow to the retina. The retina is the light-sensitive layer of tissue at the back of the eyeball.
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Causes
Amaurosis fugax is not itself a disease. Instead, it is a sign of other disorders. Amaurosis fugax can occur from different causes. One cause is 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
- Alcohol abuse
- Cocaine use
- Diabetes
- Family history of stroke
- High blood pressure
- High cholesterol
- Increasing age
- Smoking (people who smoke one pack a day double their risk for a stroke)
Amaurosis fugax can also occur because of other disorders such as:
- Other eye problems, such as inflammation of the optic nerve (optic neuritis)
- Blood vessel disease called polyarteritis nodosa
- Migraine headaches
- Brain tumor
- Head injury
- Multiple sclerosis (MS), inflammation of the nerves due to the body's immune cells attacking the nervous system
- Systemic lupus erythematosus, an autoimmune disease in which the body's immune cells attack healthy tissue throughout the body
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Symptoms
Symptoms include the sudden loss of vision in one or both eyes. This usually lasts for a few seconds to several minutes. Afterward, vision returns to normal. Some people describe the loss of vision as a gray or black shade coming down over the eye.
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Exams and Tests
The health care provider will perform a complete eye and nervous system exam. In some cases, an eye exam will reveal a bright spot where the clot is blocking the retinal artery.
Tests that may be done include:
- Ultrasound or magnetic resonance angiography scan of the carotid artery to check for blood clots or plaque
- Blood tests to check cholesterol and blood sugar levels
- Tests of the heart, such as an ECG to check its electrical activity
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Treatment
Treatment of amaurosis fugax depends on its cause. When amaurosis fugax is due to a blood clot or plaque, the concern 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 to 90 minutes a day if you are overweight.
- Quit smoking.
- Most people should aim for a blood pressure below 120 to 130/80 mm Hg. 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 for 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.
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Outlook (Prognosis)
Amaurosis fugax increases your risk for stroke.
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When to Contact a Medical Professional
Contact your 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.
References
Biller J, Schneck MJ, Ruland S. Ischemic cerebrovascular disease. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 65.
Brown GC, Sharma S, Brown MM. Ocular ischemic syndrome. In: Sadda SVR, Sarraf D, Freund KB, et al, eds. Ryan's Retina. 7th ed. Philadelphia, PA: Elsevier; 2023:chap 61.
Meschia JF, Bushnell C, Boden-Albala B, et al. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(12):3754-3832. PMID: 25355838 pubmed.ncbi.nlm.nih.gov/25355838/.