Eye Stroke

Eye stroke is the everyday name for a retinal artery occlusion. The retina is the light-sensitive layer at the back of the eyeball that turns light into signals for the brain. The artery that supplies the retina branches from the carotid artery, the vessel that also carries blood to the brain. For this reason, the 2021 AHA scientific statement regards retinal artery occlusion as a form of ischemic stroke. An overview of stroke is covered on the Stroke page.

Types of Blockage

When the blockage occurs in the central retinal artery, nearly all vision in one eye is lost within seconds. When a branch is blocked, only part of the visual field goes dark, for example the upper or lower half. Because it is painless, this symptom is often mistaken for tired eyes. There is also a temporary blockage, in which vision in one eye goes dark like a curtain coming down and then returns within a few minutes (amaurosis fugax). This is equivalent to a mini-stroke (transient ischemic attack) and is covered on the Minor Stroke and TIA page. Retinal vein occlusion, which is sometimes also called an eye stroke, is a different condition treated by an eye doctor.

Why You Should Go to the Emergency Room

Retinal cells begin to be damaged within a short time after blood flow stops, so the chance of saving vision depends on speed. In addition, the source of the blockage is often the same as the source of a brain stroke, and the risk of a brain stroke rises, especially in the first few weeks. For this reason, patients are advised to go directly to the emergency room so they can be assessed like stroke patients, rather than waiting for a regular eye appointment. In the emergency room, doctors also check for other signs of stroke in the face, arms, and speech.

Link to the Heart and Neck Arteries

The blockage is usually a fragment of plaque or a small clot carried by the bloodstream. Common sources are cholesterol plaque in the carotid arteries of the neck, covered on the Atherosclerosis page, and clots from the heart in atrial fibrillation or heart valve disease. Research shows that many patients only learn they have vascular risk factors, such as hypertension, diabetes, or carotid narrowing, after a full evaluation. In people over 50, doctors also consider an inflammation of the arteries called giant cell arteritis, because it requires prompt medicine to protect the other eye.

Sudden vision loss needs to be checked as quickly as possible, ideally in the emergency room of a hospital that can treat stroke. An eye doctor examines the retina to confirm an artery blockage: the retina looks pale and swollen, sometimes with a red spot in the center, and small fragments are sometimes visible inside the vessels. In people over 50, blood tests for inflammation are done the same day because giant cell arteritis requires prompt medicine.

Once the blockage is confirmed, the evaluation follows the approach for ischemic stroke: brain MRI, carotid artery testing, an ECG and heart rhythm recording, echocardiography, and blood tests for sugar and cholesterol. These tests should be completed within the first few days so the source of the blockage can be treated before a brain stroke occurs.

Sudden loss of vision in one eye is an emergency. Call 119 or go to an emergency room near you right away, even if your vision returns on its own within a few minutes, and note the time it started. Do not wait for a scheduled eye appointment or try eye drops on your own.

Make a consultation appointment if:

• You have had a brief episode of darkened vision in one eye that has not been checked
• You have just been discharged after an eye stroke and need to find the source of the blockage
• You often have palpitations with an irregular rhythm
• Your blood pressure, blood sugar, or cholesterol is not yet under control