What Is a Retinal Artery Occlusion?

What is a retinal artery occlusion?

Most people know that having high blood pressure and heart disease is dangerous to your health. But did you know that high blood pressure can affect your vision too? Having high blood pressure can damage arteries that carry blood in the eye.

If a blood clot or cholesterol builds up and blocks blood flow in one or more of your retina’s arteries, it is called a retinal artery occlusion (RAO). This is like having a stroke (when blood flow to the brain is cut off), but in your eye instead of your brain.

There are two types of RAOs:

• Branch retinal artery occlusion (BRAO) blocks the small arteries in your retina.
• Central retinal artery occlusion (CRAO) is when the central artery in your retina becomes blocked. This is a form of a stroke in the eye, and is a risk factor for having a brain stroke. CRAO is a serious emergency, just like a brain stroke, so it is important to go to a hospital Emergency Room right away to be checked and treated immediately.

What are symptoms of a retinal artery occlusion (RAO)?

The most common symptom of a retinal artery occlusion (RAO) is sudden, painless vision loss. You may lose vision in all of one eye (due to CRAO), or in part of one eye (from BRAO). In some cases, vision may have been lost in the past but come back again due to blood clots.

Other symptoms include the sudden appearance of:

• Complete loss of vision
• Loss of your side (peripheral) vision
• Distorted vision, where things may look wavy or out of shape
• Blind spots in your vision

If you have any of these symptoms, go to a hospital Emergency Room right away! Having a trained doctor quickly find and treat RAO can help prevent a brain stroke and may help save your vision.

Who is at risk for a retinal artery occlusion (RAO)?

RAO is most commonly found in people in their 60’s—especially men, though women can have it too. Having certain health problems increases your risk of RAO. These include:

• smoking
• obesity
• older age
• heart/lung disease
• diabetes
• high cholesterol
• high blood pressure
• narrowing of the carotid (neck) artery
• blood clotting problems

How is a retinal artery occlusion (RAO) diagnosed?

If you experience sudden vision loss, you should go to a hospital Emergency Room right away. Doctors will look closely at your retina during a dilated eye exam.

Doctors may do other tests too, including:

• Fluorescein angiography. This imaging test uses a special camera to take photos of the retina. A small amount of yellow dye (fluorescein) is injected into a vein in your arm. Photos of fluorescein dye traveling throughout the retinal arteries show if arteries are blocked.
• Intraocular pressure (pressure inside the eye)
• How your pupil responds to light
• Other photos of the retina
• Optical Coherence Tomography (OCT)
• A slit lamp exam
• Testing of your side vision (visual field examination)
• Visual acuity (sharpness of vision), to see how well you can read an eye chart

People who have RAOs are at risk for having a brain stroke. The risk of having a stroke is very high right after and up to four weeks after having RAO.

Your ophthalmologist or regular doctor may order other tests to help look for artery blockage, including:

• an ultrasound of your carotid arteries (the main blood vessels in your neck that send blood to your eyes and brain). This test uses soundwaves to create images of the organs and tissues inside your body.
• imaging tests looking at the blood vessels in the head and the neck.
• an echocardiogram (an ultrasound of the heart).

Treatment

Certain studies have shown having an untreated RAO for just over an hour and a half can lead to permanent vision loss. Also, someone who is having RAO may also be having a brain stroke at the same time. This is why it is so important to get to a hospital Emergency Room right away if you have RAO symptoms.

There are a few treatments for retinal artery occlusion (RAO) that doctors may try, but these treatments have not been proven to help all of the time.

Treatments may include:

• Breathing in a carbon dioxide-oxygen mixture. This causes the arteries of the retina to widen (dilate).
• Removing some liquid from the eye, or massaging the eye to allow the clot to move away from the center of the retina.
• In some cases, having a drug given through a vein (infusion) to break up clots. Only certain people may be given this drug. For the best chance of working, this treatment has to be given within several hours of losing vision. Also, there is a risk of bleeding in the brain with this medicine.

Often people lose vision permanently, especially with a central retinal artery occlusion. Some people do get their vision back after having RAO, although they may not see as well as they did before.

Even if your vision does not improve after RAO, it is important to continue seeing your ophthalmologist. There may be more eye complications from RAO later, so your ophthalmologist will want to monitor and treat any problems to help prevent further vision loss.