Introduction
Amaurosis fugax is a medical condition related to the lack or reduced blood flow of the eye in which a person cannot see through one or both eyes. Other names of amaurosis fugax are transient monocular blindness, temporary vision loss, and transient monocular visual loss. Usually, it is not a condition but a symptom of an underlying condition in which the blood supply to the eye decreases.
What Are the Symptoms of Amaurosis Fugax?
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Amaurosis fugax is a temporary loss of vision in either or both eyes.
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Other symptoms include monocular blindness (vision loss of one eye), dimming, fogging, or blurring. Total or sectional vision loss can occur, and the duration is only a few seconds, but in some cases may last for a few minutes or even for a few hours.
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The duration of vision loss usually depends on the underlying cause. For example, if blindness is due to papilledema (swelling in the disc of the eye due to increased eye pressure), it is only for seconds.
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When an atherosclerotic (a condition in which plaque deposits in the vessel) carotid artery defect is present, vision loss lasts for a few minutes.
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The presence of additional symptoms depends on the cause of the condition. Usually, a transient ischemic attack (TIA) results in amaurosis fugax (lack of blood supply for a few seconds).
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TIA’s are considered precursors of stroke. However, stroke-like symptoms that occur due to TIA are temporary.
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TIA’s symptoms include difficulty in speaking, a prominent facial droop on one side of the face, and sudden onset of weakness, usually on one side of the body, along with temporary blindness.
What Is the Cause of Amaurosis Fugax?
The main reason for amaurosis fugax is the lack of blood supply due to blockage of the central retinal artery, which is the main artery that supplies blood to the retina. Mainly the blood clot or piece of plaque is the most common cause of amaurosis fugax. The most common reason is plaque or a blood clot formation in the same carotid artery.
What Are the Risk Factors of Amaurosis Fugax?
A history of heart disease in patients is the most common risk factor. Other factors include high blood pressure, high cholesterol, smoking, or patients with a history of alcohol and tobacco abuse.
Other reasons that can cause the condition include:
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Certain brain tumors.
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Previous head injury.
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Multiple sclerosis (a disease of the immune system in which the immune system eats away the protective covering of nerves).
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History of systemic lupus erythematosus (an inflammatory disease in which the body's immune system starts attacking its tissue).
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Migraine or headache.
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Optic neuritis (inflammation of the optic nerve).
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Polyarteritis nodosa is a disease of blood vessels.
Diseases of the nervous system can affect blood flow to the head and cause amaurosis fugax. For example, in vasospasm (a condition in which brain blood vessels become narrow), eye blood vessels suddenly tighten, and restriction of blood flow to the eye occurs. Some conditions like strenuous exercise, vigorous running, and sexual intercourse can cause vasospasm.
How Is Amaurosis Fugax Diagnosed?
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Usually, for diagnosis, proper medical history and complete assessment of the presence of vascular risk factors should be examined.
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Systemic diseases such as hypertension, diabetes, hyperlipidemia, and cardiac disease should be checked.
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Patients should ask about tobacco usage.
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A detailed physical examination of the body that includes a complete eye examination should be done.
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Assessment of optic nerve and optic disc can be checked properly.
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Proper auscultation of the carotid arteries should be done. In addition, a proper examination of the heart should be done.
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If the patient is having symptoms of amaurosis fugax, then immediate actions should be taken. But first, schedule a visit to a doctor. The doctor will take a good medical history and physical examination of the body, including the eyes. The doctor may also do other tests:
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In order to identify a blockage, imaging scans can locate damage in the blood eyes' blood vessels and test to check cholesterol levels.
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In order to identify heartbeat and pattern, an electrocardiogram or EKG is done. These are tests to determine heart conditions.
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Doppler ultrasound is an imaging technique in which high-frequency sound waves pass from red blood cells so carotid arterial perfusion (oxygen level) can be assessed in the tissues.
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Magnetic resonance angiography is used to evaluate arterial blood flow.
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Computed tomography (CT) angiography is also used to evaluate the flow of the arteries.
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The patient’s age, symptoms, and overall health considerations are essential for proper diagnosis.
What Is the Treatment for Amaurosis Fugax?
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If, after proper diagnosis, there is any systemic disease or vascular disease, then the first treatment of the condition and cause should be done.
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If hypertension, diabetes, or hyperlipidemia (increased lipid in the body) are present, these should be corrected.
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In most asymptomatic cases, conservative treatment gives relief to the patients.
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Medications such as Anticoagulants are enough in mild cases.
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If the reason for amaurosis fugax is an atherosclerotic lesion (presence of plaque accumulation in the blood vessel), then Aspirin is the treatment of choice for such patients.
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If in the carotid artery there is a presence of mild stenosis (blood vessels become narrow), minimally invasive techniques, such as carotid stenting done in which a stent is placed to broaden the narrow affected part.
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But when stenosis (narrowing) is greater than 70 %, it indicates endarterectomy. In an endarterectomy, an inner lining of the artery is removed along with deposited material on the artery.
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Amaurosis fugax is considered a favorable indication for carotid endarterectomy. If the stenosis condition is left untreated, there is a high risk of stroke (sudden blockage of the whole artery). Patients after carotid endarterectomy have a very low risk for postoperative stroke (after operation).
What Are the Complications of Amaurosis Fugax?
Amaurosis fugax is considered a fleeting (short duration) condition, and its symptoms last from a few minutes to a few hours, but it indicates a severe underlying medical condition. Furthermore, it can be deadly as it is considered an indicator of stroke. Therefore, signs of ignorance can harm a patient's future condition.
What Is the Prognosis for Amaurosis Fugax?
As the condition is serious because it is a symptom of the condition, it indicates that the person might experience a stroke in the future. So immediately after experiencing temporary blindness, patients should visit a doctor to avoid further worsening the condition. The sooner one treats the condition, the less severity or complications will appear in the future.
Conclusion
Amaurosis fugax is a symptom of different conditions, but it is not a disease. But ignorance of symptoms can be detrimental to patients, so the immediate diagnosis of the underlying cause is mandatory. After proper diagnosis, prompt treatment of symptoms and causes should be done to avoid further complications.
