Transient visual loss is the term used to describe loss of part or all of the vision in one or both eyes temporarily. Some people do not experience a complete loss of the affected vision and instead describe the abnormality as “blurring” or like “looking through a veil.” The vision typically returns to normal before a person is able to be examined by an ophthalmologist, so the examination may be normal. Undergoing an eye examination is still very important, as diagnostic clues can sometimes help an eye doctor narrow down the possible causes. Even if the vision returns to normal, transient vision loss can be a sign of serious abnormalities of the eye, brain, or blood vessels that can lead to permanent vision loss or even to a brain stroke, without prompt recognition and treatment.
If the vision loss episode is thought to be due to a blood clot blocking the flow of blood to a part of your eye or brain, this is treated in the same way as a transient ischemic attack (TIA; temporary blood flow interruption in the brain) or stroke. Urgent evaluation in an emergency department that can treat patients for stroke is necessary. There, health care providers can evaluate the patient, and if a blood clot is suspected to be the cause of transient visual loss, further testing may be performed. Evaluations may include an MRI of the brain, blood vessel imaging of the head and neck, bloodwork, heart rhythm monitoring (electrocardiogram), and an ultrasound of the heart (echocardiogram). The results of these tests will help determine the best treatments to help protect your vision and brain from future damage. Medicines that reduce blood clotting such as aspirin may be started, and in some cases, a surgery to open up blockage in a neck artery may be recommended.
Other causes of transient visual loss can still be serious or may be benign. With details from the description of your visual loss events and the help of other tests, your health care provider can provide more details about the specific cause of your visual loss episodes.
As your eye examination may be normal after an episode of transient visual loss, the details of your episodes are very important in determining the cause and what to do next. Keeping careful track of the answers to the following questions can help narrow down the possibilities:
Amaurosis fugax is a mix of terms from Greek (amauros – “dark”) and Latin (fugax – “fleeting”) that usually means a temporary loss of vision in one eye from an interruption in blood flow. This term is not typically used to describe other forms of transient visual loss.
Migraine with aura, from the Mayo Clinic
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