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Central Retinal Artery Occlusion

​​​​​​​​​​​​​​​​​​​​​A central retinal artery occlusion blocks blood to your eye and is a medical emergency.

The blockage, often a blood clot, causes loss of vision that can be permanent or partial.

Marshfield Clinic Eye Specialists diagnose and treat conditions and diseases of the eye.

Central Retinal Artery Occlusion

When one of the vessels that carry blood to your eye’s retina gets blocked, it can cause you to lose your eyesight.

This problem often happens suddenly and without any pain. This called a central retinal artery occlusion (CRAO).

Your retina is the layer of nerves at the back of your inner eye that sense light. Like a tiny video camera, your retina turns images into electrical signals.

Your optic nerve carries these signals to your brain. If a blockage of a blood vessel happens in your retina, it can be very serious.

The blockage usually comes from a clot or fatty deposit in your blood vessel. This is an emergency.

You will need medical help right away. If the blood clot breaks free and moves to the brain, it can cause a stroke.

The after effects of CRAO can come quickly and be very serious. Most often you will have some loss of eyesight.

Even after treatment, your eyesight may not get better.A disease that is like CRAO is branch retinal artery occlusion. This is a blockage in 1 branch of the arteries that brings blood to your retina.

With this form of the disease, recovery is more likely. After treatment you are often able to keep fair to good eyesight.

What causes central retinal artery occlusion?

Central retinal artery occlusion is a blockage of the central retinal artery. The blockage usually comes from a clot or fatty deposit in your blood vessel.  

Who is at risk for central retinal artery occlusion?

High blood pressure and aging are the main risks for CRAO. Glaucoma and diabetes can also raise your risk. So can problems in which your blood is thicker and stickier than normal. In women, the problem has been linked to the use of birth control pills.

What are the symptoms of central retinal artery occlusion?

The signs of CRAO are easy to spot. They are:

  • Sudden blindness in 1 of your eyes

  • Sudden, complete blurring of eyesight in 1 eye

  • Steady loss of eyesight in 1 eye over a few weeks

The symptoms may last a few seconds or minutes. Or, they might be permanent. If you have only partial blurring or loss of eyesight, you likely have branch retinal artery occlusion.

The symptoms of CRAO may look like other medical problems. Always talk with your health care provider for a diagnosis.

How is central retinal artery occlusion diagnosed?

If your health care provider thinks that you have CRAO, he or she will do a physical exam of the eye. Your eye will be dilated first. Your health care provider may also do a number of other eye tests. These are done to find out the type of blockage and how much damage you have. One eye test that can make a clear diagnosis is called a fundoscopy. This test is sometimes done with a biomicroscope and slit lamp.

You will be tested for high blood pressure, glaucoma, and diabetes. If you are young, your health care provider may check whether your blood is thicker than normal. This can be done with a blood test called a complete blood count.

Your health care provider may also make other checks of your heart health to see if you have problems with clotting elsewhere. These health problems are often related.

How is central retinal artery occlusion treated?

Your health care provider will figure out the best treatment for you based on:

  • Your age

  • Your overall health and medical history

  • How sick you are

  • How well you can handle specific medicines, procedures, or therapies

  • How long the condition is expected to last

  • Your opinion or preference

The symptoms of CRAO sometimes look like other medical problems. Always see your health care provider for a diagnosis.

Doctors sometimes use a laser to fix the blockage. Experts say that if you arrive at the hospital with at least 20/40 vision, you will likely have fairly good eyesight later on. But if your vision in the eye is 20/200 or worse, the outlook for recovery is not good.

Some people have been treated with high pressure (hyperbaric) oxygen. The retina takes in more oxygen than any other organ in the body. This makes the retina more likely to be harmed if a blockage keeps oxygen-rich blood from reaching it.

In many cases, hyperbaric oxygen therapy can give enough extra oxygen to keep the retina healthy until normal blood flow returns. You will breathe pure oxygen in a special room. The extra oxygen in the blood can sometimes cause the arteries in your retina to get wider. This can help your eyesight get better.

How well this works depends on the type of blockage. It also depends on how quickly therapy begins after the blockage forms. This therapy may work best if started within 8 hours after the blockage begins.

In other cases, your doctor might try to open up the retinas manually. He or she will do this by massaging the affected area. Or he or she may use a clot-busting drug such as a tissue-plasminogen activator or t-PA. Several other treatments have been tried but they don’t work as well.

What are the complications of central retinal artery occlusion?

Central retinal artery occlusion can lead to partial to permanent loss of eyesight in the affected eye.

Can central retinal artery occlusion be prevented?

Central retinal artery occlusion is often linked to diabetes or heart problems. But these health problems don’t cause it. A good preventive step is to keep your heart healthy. You can do this by:

  • Staying at a healthy weight

  • Eating a healthy diet

  • Exercising regularly

  • Not smoking

Also, if you have diabetes, work to keep your blood sugar at a healthy level.

Key points

  • Central retinal artery occlusion is the blockage of blood to the retina of 1 eye.

  • It usually causes sudden loss of eyesight in 1 eye.

  • You are higher risk if you are older or have high blood pressure, glaucoma, or diabetes.

  • You are also at higher risk if your blood is thicker and stickier than normal.

  • Central retinal artery occlusion is a medical emergency. You need to get medical help right away.

  • Treatment choices include laser surgery, hyperbaric oxygen therapy, and clot-busting drugs.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

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