Amaurosis fugax is a condition in which a person cannot see out of one or both eyes due to a lack of blood flow to the eye(s). The condition is a symptom of an underlying problem, such as a blood clot or insufficient blood flow to the blood vessels that supply the eye. Other names for amaurosis fugax include transient monocular blindness, transient monocular visual loss, or temporary visual loss.

When a person experiences amaurosis fugax, their vision may suddenly appear to cloud over. This is typically a temporary effect that can last anywhere from a few seconds to several minutes. Some people have described the occurrence of amaurosis fugax as feeling as if someone has pulled a shade over their eye.

In many instances, amaurosis fugax is a symptom of a transient ischemic attack (TIA). A TIA is a precursor to a stroke. TIAs cause stroke-like symptoms that are temporary. In addition to temporary blindness, other symptoms associated with TIAs include difficulty speaking, a facial droop on one side of the face, and sudden weakness on one side of the body.

When blood flow is blocked to the central retinal artery that supplies blood to the eyes, amaurosis fugax occurs. A common cause of amaurosis fugax is a blockage of blood flow to the eye from a piece of plaque or a blood clot. The most of the condition is plaque or a blood clot in the same carotid artery where a person experiences the blindness.

The risk factors for this occurrence include having a history of heart disease, high blood pressure, high cholesterol, smoking, or a history of alcohol or cocaine abuse.

Other underlying causes of the condition include:

  • brain tumor
  • head injury
  • history of multiple sclerosis
  • history of systemic lupus erythematosus
  • migraine headaches
  • optic neuritis, an inflammation of the optic nerve
  • polyarteritis nodosa, a disease that affects the blood vessels

Diseases that affect the nervous system and/or blood flow to the head can all typically cause amaurosis fugax to occur. In addition to these causes, a person can experience amaurosis fugax due to a vasospasm, where the blood vessels in the eye suddenly tighten, restricting blood flow. Strenuous exercise, long-distance running, and sexual intercourse can all cause vasospasm.

Treatment for amaurosis fugax involves identifying and treating the underlying medical condition. If the condition is related to high cholesterol levels and/or blood clots, this indicates a person is at high risk for a stroke. A stroke occurs when a blood clot lodges in a blood vessel in the brain, stopping blood flow to the brain. As a result, some of the most immediate treatments are related to reducing the likelihood for stroke. Examples include:

  • taking blood thinners, such as aspirin or warfarin (Coumadin)
  • undergoing a surgical procedure known as a carotid endarterectomy, where a doctor will “clean out” the plaque potentially blocking the carotid arteries
  • taking medications to lower blood pressure

In addition to these medical treatments, a doctor will recommend at-home treatments. Examples include:

  • refraining from eating high-fat foods, such as fried, processed, or fast foods
  • stopping smoking
  • exercising at least 30 minutes a day for most days of the week
  • managing chronic conditions, such as diabetes, high blood pressure, or high cholesterol

Healthy habits and taking steps to maintain an ideal weight can help a person reduce their risk for amaurosis fugax.

If you’re experiencing symptoms of amaurosis fugax, don’t ignore them. Call your doctor. They will ask you about your symptoms and take a medical history. Your doctor will then perform a physical exam, including an eye exam. Your doctor may also order testing, which can include:

  • imaging scans to identify blockages or damage to the blood vessels in your eyes
  • blood testing to determine your cholesterol levels as well as likelihood of blood clotting
  • an electrocardiogram, or EKG, to identify irregularities in your heartbeat that could lead to amaurosis fugax

A doctor will consider your symptoms, age, and overall health when making a diagnosis related to amaurosis fugax and temporary vision loss.

Although amaurosis fugax is a fleeting condition that causes symptoms lasting anywhere from a few minutes to an hour, it is often a concerning indicator of an underlying medical condition. This includes an increased risk for stroke, which can be deadly. If a person ignores these signs, they are at risk for more severe complications.

Amaurosis fugax is a concerning symptom because it can indicate the likelihood a person will experience a stroke. If you experience even a short episode of temporary blindness, you should contact your doctor immediately. In the case of TIAs, the sooner a condition is treated, the less likely severe complications will occur.