“Fleeting darkness or blindness” or amaurosis fugax in Greek, is a sudden painless temporary loss of vision in one or both eyes irrespective of the cause. However, it is more accurate to reserve the term amaurosis fugax for episodes resulting from ischemia of the ocular vessels. It usually lasts for a few seconds to a few minutes. Another name is (transient mononuclear vision loss).
It is common for patients to present to an ophthalmologist with a history of a transient visual disturbance (TVD). Vision is often normal again by the time the person seeks medical attention, which can make it harder to find the cause. People often describe it as a curtain or shade coming over their eye.
amaurosis fugax is not a disease itself. Instead, it is a warning sign of other disorders. It can occur from different causes, one cause is blockage of blood flow to or from the retina (retinal artery occlusion or retinal vein occlusion), blockage often happen when a blood clot or a piece of cholesterol plaque travels from a larger artery, such as the carotid artery in the neck or the coronary artery in the heart, to the eye blocking the retinal artery. It can also happen when blood flow to an eye is low. Other causes could be:
- Local ocular condition, 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.
Because of the many causes of transient visual disturbance, a structured approach to both the assessment and the management of these patients is essential. The likely causes of transient vision loss vary according to the age of the patient. Ischemic causes are more likely in patients older than 45 years; however, cases have been reported in children having impending central retinal artery occlusion and central retinal vein occlusion.
Investigations usually depend on the likely cause. If an ischemic event is suspected, then an evaluation of any cardiovascular and cerebrovascular risk factors is needed. If the transient vision loss is monocular, the carotid
system should be investigated, usually via carotid Doppler ultrasonography. Other investigations may include echocardiography, a complete blood count (to rule out anemia), and inflammatory markers when giant cell arteritis is suspected. Neuroimaging is important for ruling out intracranial pathology affecting the visual pathway, particularly in patients with binocular disturbance. In cases where the diagnosis is uncertain, adequate follow-up care is important. Children with unexplained transient visual disturbances should be closely monitored.
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 that a person is at high risk for a stroke. As a result, a doctor will recommend some lifestyle changes to decrease the risk of stroke as:
-Maintaining a balanced healthy diet, refraining from eating high-fat foods, such as fried, processed, or fast foods
-at least 150 mins per week of moderate aerobic exercise.
Sudden vision loss is a medical emergency that requires seeking medical attention quickly. Evaluation may include an eye examination and a neurological examination to test the function of the eyes and brain. The examination and tests are performed to look for specific eye problems as well as generalized medical conditions that may be related to the vision loss.
Investigations usually depend on the likely cause. If an ischemic event is suspected, then an evaluation of any cardiovascular and cerebrovascular risk factors is needed. If the transient vision loss is monocular, the carotid
system should be investigated, usually via carotid Doppler ultrasonography. Other investigations may include echocardiography, a complete blood count (to rule out anemia), and inflammatory markers when giant cell arteritis is suspected. Neuroimaging is important for ruling out intracranial pathology affecting the visual pathway, particularly in patients with binocular disturbance. In cases where the diagnosis is uncertain, adequate follow-up care is important. Children with unexplained transient visual disturbances should be closely monitored.
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 that a person is at high risk for a stroke. As a result, a doctor will recommend some lifestyle changes to decrease the risk of stroke as:
-Maintaining a balanced healthy diet, refraining from eating high-fat foods, such as fried, processed, or fast foods
-at least 150 mins per week of moderate aerobic exercise. -stopping smoking
-Well control of 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.
Your doctor also may prescribe some medications:
-Blood thinners, such as aspirin or warfarin (Coumadin), empiric antiplatelet therapy (eg, daily aspirin) may be indicated while the evaluation is in progress for transient vision loss in patients with vasculopathy. -undergoing a surgical procedure known as a carotid endarterectomy, where a doctor will “clean out” the plaque potentially blocking the carotid arteries may also be required.