Eye Stroke

What is an eye stroke?

An eye stroke is a term for what happens when something blocks an artery that supplies blood to your retina. The medical name for an eye stroke is “retinal artery occlusion.” Occlusion means blockage. The blockage is often a blood clot.

Your retina is the part of your eye that communicates with your brain to turn light into images.

You can also have a blockage in the vein serving your retina. This is called a retinal vein occlusion.

Eye strokes (retinal artery occlusions) are medical emergencies.

Are there different types of eye strokes?

A retinal artery occlusion may have different names based on the location of the blockage. The terms for these can also apply to blockages in veins. Types of retinal artery occlusions include:

• A central retinal artery occlusion (CRAO): This term describes a blockage in the main artery in your eye, which would be like the trunk of a tree. The effects of the stroke can be seen throughout the eye.
• A branch retinal artery occlusion (BRAO): This term refers to a blockage in one of the smaller arteries in your eye, like a branch connected to the trunk of a tree. The effects of the blockage can be seen in a smaller area of the eye.
• A twig retinal artery occlusion: This term describes a blockage in an even smaller blood vessel, like a twig that is part of a branch connected to the trunk of a tree.

How common are eye strokes?

The number of people who have retinal artery occlusion, or eye stroke, is estimated at about 1 to 2 per 100,000 people each year.

What are the signs and symptoms of an eye stroke?

The symptoms of an eye stroke usually don’t include pain. The first and main symptom is usually a sudden loss of vision or change in vision in one eye that may include:

• Floaters and flashes.
• Blurred vision.
• Blind spots or darkness.
• Vision changes that start out small but get worse over time.

What causes a stroke in the eye?

An eye stroke is caused by an interruption of blood flow to your retina. The blockage can be caused by something solid like plaque or infection that breaks off from another part of your body, like the inside of your heart or another artery. This type of blockage is called an embolism.

The blockage can also be caused by blood getting thicker and clotting. This type of blockage is called thrombosis.

These blockages cause fluid to leak and ocular (a term that refers to your vision or eyes) pressure to increase. This pressure can damage the optic nerve, which happens with glaucoma.

What are the risk factors for having an eye stroke?

Most of the risk factors for having a stroke in one of your eyes are similar to the risk factors for having a stroke in general. These things include:

• Having high blood pressure (hypertension).
• Having high cholesterol (hyperlipidemia).
• Having a build-up of plaque in your blood vessels (atherosclerosis).
• Having coronary artery disease.
• Surviving a previous stroke.
• Being older than 60.
• Being a man or a person assigned male at birth.

How is an eye stroke diagnosed?

A sudden complete or partial loss of vision in one eye is a medical emergency. Your provider may:

• Take a medical history and ask about your symptoms.
• Do a complete eye exam. This includes fundoscopy (ophthalmoscopy), where your provider uses a bright light and an ophthalmoscope to look at your eyes.
• Order fluorescein angiography tests. This type of test uses a special dye that shows the way that your blood flows in your eyes.
• Order color fundus photography tests. This test provides images of the fundus, the part of your eye that contains your retina.
• Order optical coherence tomography. This imaging test shows the blood vessels in your retina.

If your provider thinks you might have a disorder like giant cell arteritis (temporal arteritis), they may order other tests, including:

• An ultrasound.
• An echocardiogram.
• Blood tests to check for markers of inflammation.

How is an eye stroke treated?

Treatments for an eye stroke include:

• Medications to reduce pressure in your eye or to dissolve the blood clot.
• Laser treatment to close up leaking blood vessels.
• Massaging the closed eye.
• Paracentesis, which involves using a needle to take fluid from your eye to relieve pressure.
• Hyperbaric oxygen therapy, which involves breathing pure oxygen in a special chamber.

How can I reduce my risk of developing an eye stroke?

You may be able to reduce your risk of an eye stroke by:

• Eating a healthy diet and getting enough exercise.
• Keeping your blood sugar levels steady if you have diabetes.
• Managing your blood pressure, blood cholesterol and eye pressure levels.
• Having regular appointments with your eye care provider.
• Quitting smoking.

What can I expect if I have an eye stroke?

Some eye strokes cause more damage than others. The branch or twig retinal artery occlusions involve smaller portions of your eye than central retinal artery occlusions. Even with treatment, you may have some vision loss.

Having an eye stroke may be an indication that you are at risk of having a brain stroke. Many of the risk factors are the same for both conditions. Speak with your provider to see if you may be at risk.

When should I see my healthcare provider?

You should get immediate help if you suddenly lose vision in one eye. Eye strokes almost always affect just one eye.

Seek medical help even if your vision loss is temporary. Temporary vision loss can be caused by a “mini-stroke” in your eye.

A note from Cleveland Clinic

Having any type of vision loss, even temporarily, can be scary. It’s very important that you seek help immediately if you have vision loss, especially if it’s only in one eye. Just like for a stroke in your brain, getting immediate treatment is best for an eye stroke. Early treatment generally leads to the best outcomes.