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Retinal Vein Occlusion (BRVO and CRVO)

What is Retinal Vein Occlusion (RVO)?

A retinal vein occlusion occurs when one of the veins of the retina becomes blocked and cannot drain blood from the retina normally. This blockage leads to a backup of blood and fluid into the retina and can be seen in the retina as hemorrhages. The amount of swelling in the retina varies and depends on the degree of blockage of the retinal vein.

There are two types of retinal vein occlusion:

Central Retinal Vein Occlusion (CRVO)

If the blockage involves the central vein to the retina, located at the optic nerve, it is called a central retinal vein occlusion. In these cases, hemorrhages can be scattered throughout the retina, and often the central portion of the retina, the macula, can become swollen.

Branch Retinal Vein Occlusion (BRVO)

If the blockage involves only one of the smaller retinal veins, it is called a branch retinal vein occlusion. In these cases, hemorrhages and swelling are limited to the area of the retina that is drained by that particular vein.


Symptoms of a retinal vein occlusion can vary based on the severity of the blockage in the vein and amount of swelling in the retina. It typically occurs in just one eye, and common symptoms include:

  • Painless loss of vision
  • Blurry vision
  • Floaters — dark spots or lines in your vision
  • In severe cases, pain from increased eye pressure

Risk Factors

  • High blood pressure
  • Diabetes
  • Glaucoma
  • Age 50+
  • Arteriosclerosis (hardening of the arteries)
  • Blood clotting disorders

To lower your risk, you should do the following:

  • Eat a low-fat diet
  • Maintain an ideal weight
  • Exercise regularly
  • Avoid smoking


Your doctor can diagnose a CRVO or BRVO when examining your eyes based on the appearance of hemorrhages and swelling in the retina. Other diagnostic tests such as fluorescein angiogram and optical coherence tomography (OCT) can be performed to examine the degree of blockage of the vein and the amount of swelling present in the retina.


There is no cure for a vein occlusion. However, the main reason for decreased vision from a retinal vein occlusion is swelling in the central part of the retina called macular edema. Treatments for swelling include:

  • Steroid injection
  • Injection with medicines that decrease blood vessel leakage
    (Avastin, Lucentis, Eylea)
  • Laser treatment

In mild vein occlusions, often there is no significant swelling, and no treatment is indicated. In severe cases of CRVO, abnormal blood vessels can develop that can lead to glaucoma. These cases are often treated with laser and/or injection with a medication to decrease blood vessel leakage. Some patients do require surgery to control eye pressure even after laser or injections.