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Retinal artery occlusion is a blockage of the blood supply in the arteries to the retina -- the light-sensitive tissue in the back of the eye.

Alternative Names:

Central retinal artery occlusion; Branch retinal artery occlusion; CRAO; BRAO

Causes, incidence, and risk factors:

Retinal arteries may become blocked by a blood clot or substances (such as fat or plaque) that get stuck in the arteries. These blockages may occur due to hardening of the arteries in the eye.

Also, clots may travel from other parts of the body and block an artery in the retina. A common source of a clot would be from the carotid artery in the neck or from the heart lining.

Most clots are caused by conditions such as:

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

Retinal artery blockage or occlusions may last from only a few seconds to a few minutes. They also may cause permanent vision loss. The amount of vision loss is partly related to the location of the blockage.

People with retinal arterial occlusion, whether it is temporary or permanent, have a risk of stroke because clots may also move to the brain.

Retinal vessel occlusion more often affects older people. Risk factors are related to the disorders that cause the blockage.

  • Sudden blurring or loss of vision in all or part of one eye

Signs and tests:

Tests to evaluate the retina may include:

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

  • Echocardiogram
  • Heart monitor for abnormal heart rhythm
  • Ultrasound or Doppler ultrasound of the carotid arteries

Other tests may include:

  • Blood pressure
  • Cholesterol and triglyceride levels
  • Complete physical exam


Breathing in (inhaling) a carbon dioxide-oxygen mixture has been used to treat blockages in the arteries. This treatment causes the arteries of the retina to widen (dilate). It may allow the clot to move down the artery and sometimes break up, which reduces the area of the retina that is affected.

The health care provider should look for the cause of the blockage. Blockages may be signs of a life-threatening medical problem. Patients with retinal artery occlusions should be screened for:

  • Cranial arteritis
  • Carotid artery blockage
  • Heart rhythm disturbances
  • Heart valve disease
  • High blood pressure

The use of the clot-busting drug, tissue plasminogen activator (tPA), within a few hours of retinal artery occlusion may be helpful.

Support Groups:

Expectations (prognosis):

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

  • Partial or complete loss of vision in the affected eye
  • Similar problem occurring again in the same or the other eye
  • Stroke

Calling your health care provider:

Call your health care 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 of retinal artery occlusion. These include:

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

Aspirin is commonly used to prevent the artery from becoming blocked again. It is also helpful to control atrial fibrillation.


Vortmann M, Schneider JI. Acute monocular visual loss. Emerg Med Clin North Am. 2008;26:73-96.

Pokhrel PK, Loftus SA. Ocular emergencies. Am Fam Physician. 2007;76:829-836.

Review Date: 4/22/2008
Reviewed By: Andrew A. Dahl, MD, F.A.C.S., Director of Ophthalmology Training, Institute for Family Health, Assistant Professor of Ophthalmology, New York College of Medicine, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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