What to Know About Eye Strokes: Symptoms, Causes, and More

Medically Reviewed By William C. Lloyd III, MD, FACS

An eye stroke occurs when the artery or vein that exchanges oxygen to the retina gets blocked or has reduced blood flow. It can cause symptoms such as painless loss of vision, vision changes, and eye floaters. If a clot causes an eye stroke and breaks up, the loss of vision may be temporary. In other cases, the blockage may lead to permanent vision loss. 

This article looks at the types of eye strokes, how to recognize symptoms, and what can cause them. It also discusses treatment options, when to contact a doctor, and more.

What are the types of eye stroke?

A person is rubbing their eyes.
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There are four types of eye stroke. Some affect an artery in the eye, while others affect Trusted Source National Eye Institute Governmental authority Go to source the veins.

Central retinal artery occlusion

Central retinal artery occlusion (CRAO) is a blockage in the main artery in the retina, which is the ophthalmic artery.

This type of eye stroke is the most serious because the ophthalmic artery provides the most amount of blood to the retina. When it is blocked, it can cause a severe loss of vision. 

Equally important, the ophthalmic artery is the final leg of the carotid artery circulation. This means that tiny clots, cholesterol plaque fragments, and other circulating microdebris ultimately travel to the eye.

The American Society of Retina Specialists (ASRS) explains that 25% of people who do have a CRAO also happen to have an extra artery in their eyes. This is called a cilioretinal artery. It can actually help preserve vision if you have an eye stroke, as long as it is not blocked.

Branch retinal artery occlusion (BRAO)

Branch retinal artery occlusion (BRAO) affects smaller arteries in just one section of the retina. It may only impact a smaller region of your vision, and you may not recognize the change in your vision. In some cases, a BRAO can lead to a loss of vision on only one side of the eye. 

A BRAO may go unnoticed because the loss of vision is so small and without any other symptoms. 

Central retinal vein occlusion

Central retinal vein occlusion (CRVO) occurs when a blood clot blocks the major vein that drains blood from the retina. CRVO can be either ischemic or nonischemic.

Nonischemic CRVO is a milder form of CRVO, in which the blood vessels leak. Ischemic CRVO is a rapid, more severe form of CRVO that results in decreased blood flow to the retina.

Most people who experience CRVO experience the less severe nonischemic form.

Branch retinal vein occlusion

In some ways, branch retinal vein occlusion (BRVO) is similar to CRVO.

However, BRVO occurs where small arteries and veins cross each other. Atherosclerosis of the nearby small retinal branch artery causes compression and obstruction of the retinal vein.

What are the symptoms of an eye stroke?

The most common symptom of an eye stroke is pain-free loss of vision in one eye. This can affect all your vision or part of your vision, such as only the side of your eye. Vision may also appear blurry.

According to the American Academy of Ophthalmology, you may notice vision changes very suddenly or more slowly. They can develop over the course of several hours or even days. 

Some people may also notice an increase in floaters in their eyes as a result of blood leaking from the retina. Floaters can look like dark spots, lines, or “spiderwebs” that you cannot focus on. 

However, keep in mind that floaters are also usual for most people, so this is not always a cause for concern. 

Many times, eye strokes do not cause pain. However, in very severe cases, some people may also feel pain and pressure in their eye. 

Learn more about vision changes.

What causes an eye stroke?

An eye stroke can happen as a result of blocked or poor blood flow to the optic nerve, which is the nerve in the eye. Reduced blood pressure and flow to the eye nerves can damage nerve tissue and vision. 

There is no clear cause for a CRVO eye stroke. The National Eye Institute Trusted Source National Eye Institute Governmental authority Go to source explains that eye strokes in the retinal veins are more likely to develop in people who are:

Retinal artery eye strokes occur when a blood clot or cholesterol blocks the retinal artery. This is more likely to happen in people with the following conditions:

  • carotid artery disease (CAD)
  • problems with the heart valves
  • heart rhythm disorders
  • diabetes
  • high blood pressure
  • blood clotting disorders 
  • oral contraceptive use
  • pregnancy
  • abnormal blood platelet levels

Contact your doctor if you have concerns about the risk factors for an eye stroke.

Learn more about what can cause vision loss.

What are the treatments for an eye stroke?

There are no cures for either CRAO or CRVO, but there are some treatments that may help. 

However, treatments for any blockages in the eyes must be given as early as possible. Most treatments are aimed at catching an early blockage and preventing the damage from getting worse. 

Some of the treatments a doctor may offer for a retinal artery eye stroke include:

  • dilating the retinal artery with an inhaled mixture of oxygen and carbon dioxide to dislodge the clot
  • using a needle to remove fluid from the front of the eye
  • medication to reduce eye pressure
  • manual thumb massage to dislodge the clot 

For a vein eye stroke, a doctor may try Trusted Source National Eye Institute Governmental authority Go to source :

  • steroid medications to reduce swelling
  • an injection with anti-VEGF medication to bring down swelling
  • laser treatment to help prevent additional swelling in the retina 

There is also some evidence Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source that hyperbaric oxygen treatment may help with an eye stroke, although this is not routine practice. 

The exact treatment for an eye stroke will depend on how severe your condition is and how long the blockage has been occurring. Some people may also need to repeat treatments over time to help prevent further damage. 

What can I expect during recovery from an eye stroke?

Your doctor will help guide your exact recovery plan, but for some people, it may not become apparent right away if any vision loss you experience is permanent. 

Some people may recover part or all of their vision after an eye stroke. In some situations, treatments will be administered immediately after the eye stroke and further treatment may also be necessary years later Trusted Source National Eye Institute Governmental authority Go to source .

Any kind of retinal vascular occlusion is a serious medical concern, so it is important to treat the underlying condition during recovery. This includes managing any other medical conditions you might have that could contribute to your risk of another eye stroke, such as diabetes, heart conditions, or high blood pressure. 

The problems that affected your retina could also endanger your heart, kidneys, or brain, so it is important to receive treatment for these problems or conditions.

Some healthcare facilities also offer resources such as low vision specialists that can help you adapt to changed vision after an eye stroke. 

There are also assistive devices and emotional support services to address the changes that an eye stroke can bring to you and your family. 

When should I see a doctor?

You should contact a doctor for any new or sudden changes to your vision, including:

  • seeing floaters
  • flashes of lights
  • losing full or partial vision in one or both eyes

Find out more about when to see a doctor for blurred vision.

How do doctors diagnose an eye stroke?

A doctor may diagnose an eye stroke by performing a physical exam, taking a full medical history, and asking questions about your symptoms.

Tests they may then carry out can help to:

  • measure your visual acuity and field
  • test how far your vision goes
  • dilate your eyes to look at the optic nerve and retina 
  • check your optic nerve to look for color changes or swelling 

Your doctor will be able to explain what the tests involve and answer any questions you may have.

What are the possible complications of an eye stroke?

The primary and most serious complication of an eye stroke is partial or full vision loss. 

If vision loss has already occurred, there is no guaranteed treatment that can bring it back. Some people may be able to recover some of their vision, while for others the vision loss may be permanent. 

Your doctor will be able to advise on treatments that may help to restore your vision or improve any symptoms you are experiencing.

Receiving treatment for conditions that can cause an eye stroke can help to reduce your risk of the stroke and related complications.

Can I prevent an eye stroke?

You may be able to lower your risk of developing an eye stroke by managing a medical condition that puts you at risk. This can include:

  • managing your blood sugar levels if you have diabetes
  • keeping your blood pressure at healthy levels
  • taking medications as prescribed by your doctor

It may also help if you keep up on regular eye checks with an optometrist or eye doctor. They can help identify any possible problems with your eyes and recommend treatment if needed early on. 

It might also help prevent serious complications from an eye stroke if you seek medical attention as soon as possible if you notice blurry or lost vision in one or both of your eyes. For instance, if you have an eye stroke caused by CRAO, treatment must be given within 4–6 hours to be effective. 

It is important to seek medical help as soon as you experience symptoms of an eye stroke.

Learn more

Summary

An eye stroke occurs when the blood vessels that support the eye are blocked or experience reduced blood flow. 

People with heart conditions, diabetes, and high blood pressure may be especially at risk for an eye stroke. 

If you experience an eye stroke, you might have blurry vision or lose some or all of your vision in one or both eyes. The most serious complication of an eye stroke is permanent vision loss. 

The best way to reduce the risk of losing your vision with an eye stroke is to seek treatment right away. Some people may be able to regain partial vision after an eye stroke. Managing any health conditions you have and keeping up on checkups with an eye doctor may help reduce your risk of an eye stroke. 

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2023 Feb 26
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