Amaurosis fugax is the medical term for a temporary loss of vision that occurs when blood flow to the retina is impeded. It is not a disease but an umbrella term for the symptoms that cause this effect and is usually a symptom of another disorder. The loss of vision lasts only a short amount of time, thirty seconds to five minutes, and there are no other effects associated with it. Amaurosis fugax is also known as transient monocular blindness or TMB. It is associated with carotid artery disease.
Amaurosis fugax has a variety of causes. A blood clot can block the artery that travels to the eye. A piece of plaque from the arteries surrounding the heart can also cause a clot. Other disorders that may increase the likelihood of developing temporary loss of vision include polyarteritis nodosa, brain tumor, migraine headaches, multiple sclerosis, systemic lupus erythematosus, and head injuries.
Individuals with heart disease or family history of stroke are more likely to develop the plaque that might eventually break free and travel to the retina. Non-medical causes include smoking, alcohol abuse, and cocaine use. Sometimes a person's risk increases as he or she ages and other cardiovascular problems develop.
Patients who experience temporary blindness often report an initial "curtain" or "shadow" coming down over their eye. Many times, amaurosis fugax involves complete vision loss to one eye, but partial vision loss is possible, depending on the size of the obstruction or event that is causing it. The condition generally passes on its own within five to thirty minutes, with the feeling of stepping outside into the sunlight as the eyes return to normal.
Some patients experience an episode of temporary blindness from exposure to bright lights, particularly in people with the ocular ischemic syndrome. Like other instances, the effect is temporary, and people report fully restored vision once the photoreceptors have recovered. It is not uncommon for individuals to have blurry vision or a simple decrease in their field of vision as a result of light exposure.
Treatment of amaurosis fugax is aimed at the cause rather than the disorder, since it is an indication of an underlying problem. Most people don't experience pain or discomfort with the temporary blindness, although not being able to see can lead to or exacerbate general anxiety. Medication often helps patients lower their blood cholesterol or blood pressure, and ease the symptoms of diabetes. Doctors may also encourage individuals to live and eat healthier to reduce their likelihood of developing the problem.
While temporary blindness usually affects adults older than fifty, it can strike at any age. The cause of amaurosis fugax in children is often another medical condition. In some cases, a child can develop monocular blindness during or after a migraine headache or as the result of a seizure. Children who have family members with a history of migraines are also susceptible to the condition.
By definition, amaurosis fugax is temporary. However, if the underlying issue is not resolved there is the potential for the temporary blindness to become permanent due to the increased pressure on the retina. Early diagnosis and treatment are vital because once the condition progresses to damage the retina, reversing the blindness is no longer possible.
Some patients require surgical intervention to lessen the effects of the disorder, particularly if they experience more than one or two episodes per month. Carotid surgery is an option. For those who experience temporary blindness because of blood clots, blood thinners and heart medication will help reduce recurrences of temporary blindness.
If an individual experiences temporary blindness and believes it is a result of an underlying problem, a physician can conduct tests to determine the cause and suggest treatment. A medical imaging scan can identify blockages in the arteries leading to the eye or damage to the blood vessels. Blood tests can reveal high cholesterol and the potential for clotting disorders, and an EKG can identify heart irregularities that might contribute to the condition.
A diagnosis of amaurosis fugax can be scary. Luckily, the disorder itself is usually benign and leads only to a temporary effect. Some people experience AF after heavy exercise or other exertion. A doctor may encourage the individual to reduce strenuous activity. Temporary blindness is treatable if discovered early, and rarely leads to more extensive problems.
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