Amaurosis fugax


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 eyes. 

The disease is a symptom of an underlying problem, such as a blood clot or insufficient blood flow to the blood vessels that supply the eye. 

Amaurosis fugax is also called transient monocular blindness, transient monocular visual loss, or temporary visual loss.

What are the symptoms of fleeting amaurosis ?

When a person suffers from amaurosis, the vision may suddenly appear to be clouding. This is usually a temporary effect that can last from a few seconds to several minutes. 

In many cases, amaurosis is a symptom of transient ischemic attack (TIA). 

In addition to temporary blindness, other symptoms associated with TIAs include difficulty speaking, drooping on one side of the face, and sudden weakness on one side of the body.

The causes

Amaurosis occurs when blood flow is blocked to the central retinal artery that supplies blood to the eyes. A common cause of amaurosis fugax is a blockage of blood flow to the eye by a piece of atherosclerotic plaque or a blood clot.

Risk factors include a history of heart disease, high blood pressure, high cholesterol, smoking, or a history of alcohol or cocaine abuse.

Other underlying causes of the disease include:

  • brain tumour
  • head injury
  • history of multiple sclerosis
  • history of lupus erythematosus
  • migraines
  • optic neuritis which is inflammation of the optic nerve
  • polyarteritis, a disease that affects the blood vessels

Diseases that affect the nervous system and/or blood flow to the head can all cause fleeting amaurosis. In addition to these causes, a person may experience amaurosis caused by a vasospasm, in which the blood vessels in the eye suddenly constrict, restricting blood flow. Strenuous exercise, running, and sexual intercourse can all cause vasospasm.

What are the treatments ?

Treatment for amaurosis fugax involves identifying and treating the underlying medical condition. If the condition is linked to high cholesterol levels and/or blood clots, this indicates that a person is at high risk for stroke. 

Treatments include:

  • blood thinners, such as aspirin or warfarin (Coumadin);
  • a surgery known as a carotid endarterectomy, in which a doctor will ‘clean out’ plaque potentially blocking the carotid arteries;
  • medicines to lower blood pressure.

In addition to these medical treatments, a doctor will recommend non-drug treatments:

  • avoid eating foods high in fat, such as fried, processed or fast foods,
  • stop smoking;
  • exercise at least 30 minutes a day most days of the week;
  • manage chronic diseases, such as diabetes, high blood pressure, or high cholesterol.

How is amaurosis fugax diagnosed?

Your doctor will then perform a physical exam, including an eye exam. Your doctor may also order tests, which may include:

  • imaging scans to identify blockages or damage to blood vessels in your eyes;
  • blood tests to determine your cholesterol level as well as the likelihood of blood clotting;
  • an electrocardiogram to identify irregularities in your heartbeat that could lead to fleeting amaurosis.

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

What are the complications of amaurosis?

Although amaurosis fugax is a short-lived condition that causes symptoms that last from a few minutes to an hour, it is often a worrying indicator of an underlying disease. 

This includes an increased risk of stroke, which can be fatal. If a person ignores these signs, they are at risk for more serious complications.

What is the prognosis of fleeting amaurosis?

Amaurosis fugax is a serious symptom, since it may indicate that the likelihood of a person having a stroke is high.

In the case of a transient ischemic attack, the earlier the disease is treated, the fewer serious complications there will be.