Retinal artery occlusion

Retinal arteries may become blocked when a blood clot or fat deposits get stuck in the arteries. These blockages are more likely if there is hardening of the arteries (atherosclerosis) in the eye.

Clots may travel from other parts of the body and block an artery in the retina. The most common sources of clots are the heart and carotid artery in the neck.

Most blockages occur in people with conditions such as:

• Carotid artery disease, in which the two large blood vessels in the neck become narrowed or blocked
• Diabetes
• Heart rhythm problem (mainly atrial fibrillation)
• Heart valve problem
• High levels of fat in the blood (hyperlipidemia)
• High blood pressure
• Intravenous drug abuse
• Temporal arteritis (inflammation of arteries due to an immune response)

If a branch of the retinal artery is blocked, part of the retina will not receive enough blood and oxygen. If this happens, you may lose part of your vision.

Sudden blurring or loss of vision may occur in:

• All of one eye (central retinal artery occlusion or CRAO)
• Part of one eye (branch retinal artery occlusion or BRAO)

The retinal artery occlusion may last for only a few seconds or minutes, or it may be permanent.

A blood clot in the eye may be a warning sign of clots elsewhere. A clot in the brain may cause a stroke.

Tests to evaluate the retina may include:

• Examination of the retina after dilating the pupil
• Fluorescein angiography
• Intraocular pressure
• Pupil reflex response
• Refraction
• Retinal photography
• Slit lamp examination
• Testing of side vision (visual field examination)
• Visual acuity

General tests should include:

• Blood pressure
• Blood tests, including cholesterol and triglyceride levels and the erythrocyte sedimentation rate
• Physical examination

Tests to identify the source of a clot from another part of the body:

• Echocardiogram
• Electrocardiogram (ECG)
• Heart monitor for abnormal heart rhythm
• Duplex Doppler ultrasound of the carotid arteries

There is no proven treatment for vision loss that involves the whole eye, unless it is caused by another illness that can be treated.

Several treatments may be tried. To be helpful, these treatments must be given within 2 to 4 hours after symptoms begin. However, the benefit of these treatments has never been proven, and they are rarely used.

• Breathing in (inhaling) a carbon dioxide-oxygen mixture. This treatment causes the arteries of the retina to widen (dilate).
• Massage of the eye.
• Removal of fluid from within the eye. An eye doctor uses a needle to drain a small amount of fluid from the front of the eye. This causes a sudden drop in eye pressure, which can sometimes cause the clot to move into a smaller branch artery where it will cause less damage.
• The clot-busting drug, tissue plasminogen activator (tPA).

The health care provider should look for the cause of the blockage. Blockages may be signs of a life-threatening medical problem.

People with blockages of the retinal artery may not get their vision back.

Complications may include:

• Glaucoma (CRAO only)
• Partial or complete loss of vision in the affected eye
• Stroke (due to the same factors that contribute to retinal artery occlusion, not due to the occlusion itself)

Contact your provider if you have sudden blurring or vision loss.

Measures used to prevent other blood vessel (vascular) diseases, such as coronary artery disease, may decrease the risk for retinal artery occlusion. These include:

• Eating a low-fat diet
• Exercising
• Stopping smoking
• Losing weight if you are overweight

Sometimes, blood thinners may be used to prevent the artery from becoming blocked again. Aspirin or other anti-clotting drugs are used if the problem is in the carotid arteries. Warfarin or other more potent blood thinners are used if the problem is in the heart.

Central retinal artery occlusion; CRAO; Branch retinal artery occlusion; BRAO; Vision loss - retinal artery occlusion; Blurry vision - retinal artery occlusion

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Updated by: Audrey Tai, DO, MS, Athena Eye Care, Mission Viejo, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.