Central Retinal Vein Occlusion (CRVO)

What You Need To Know

Your eyes are a marvel of the human body, but don’t forget that your eyes are also organs. Like every other organ in your body, your eyes rely on arteries to take nutrient and oxygen rich blood to them and veins to take the oxygen poor blood and waste away. Each eye has just one major artery and one major vein. This vein is known as the central retinal vein.

If the central retinal vein becomes blocked, this is known as central retinal vein occlusion, or CRVO for short. A blockage causes the vein to leak blood and fluids out into the delicate tissues of the retina. This fluid will often begin to pool in the area known as the macula (say MACK-you-la) and cause swelling. The macula is the part of the retina that is responsible for your central vision. So it’s no surprise that if this happens, the vision in the center of your visual field could become blurry. If left untreated for too long, nerve cells may begin to die and cause permanent damage to your vision.


Some people who have mild CRVO may not know it because they experience symptoms that come and go, or no symptoms at all. However, most patients who have CRVO will experience blurry and/or distorted vision, due to the leakage of fluid from the vein into the tissues of the retina. You may also experience floaters in your vision caused by blood leaking into the vitreous. In severe cases redness, pain and irritation can occur. Almost all cases of CRVO occur in just one eye.

As with any unexplained change in your vision, if you experience any of these symptoms, please see your eye professional immediately for proper diagnosis and treatment.


People who smoke, have diabetes, high blood pressure, glaucoma and/or atherosclerosis (hardened arteries) are at increased risk for developing CRVO. The exact cause of CRVO is still unknown, but you can help prevent CRVO by eating a healthy diet, not smoking and exercising regularly.

CRVO happens when a clot forms in the central retinal vein or when there is reduced blood flow in central retinal vein and it cannot properly drain the retina. There are quite a few diseases that can put people at an increased risk for blood clots. Although some doctors advise that you get tested for these diseases if you develop CRVO, we still don’t know exactly how these diseases are related to CRVO. However, CRVO may be a clue to pre-existing condition such as diabetes or high blood pressure. CRVO in both eyes at the same time or in people under 40, may be a sign that you have a disease involving a blood clotting disorder, and referral to a blood specialist may be necessary. Only an eye specialist will be able to distinguish your unique needs.

In general, younger people who develop CRVO have a better outcome than older people. In patients who do not seek treatment, CRVO may get better on its own, cause symptoms to remain the same, or symptoms may worsen.

How Is CRVO Treated?

Since the central retinal vein cannot be unclogged, the aim of treatment is to keep the swelling in the macula down. The most common treatment for CRVO involves a series of injections into the eye of a drug that works to reduce swelling by sealing off leaky blood vessels and to prevent the growth of new blood vessels likely to bleed. These injections, given by our Retinal Specialist, Dr. David W. Switzer Jr., can help to control symptoms but they are not a cure. Most patients require a series of regular injections spread out over a few years. In severe cases of CRVO the injections sometimes have to be boosted with laser treatments to control symptoms. CRVO can worsen, so if you have been diagnosed, it’s really important to see your eye doctor on a regular basis.

The bottom line is this: with early detection and treatment, most patients with CRVO can escape severe vision loss. So see your eye professional on a regular basis for checkups!

Video Library

Visit Our Video Library
© Copyright - Billings Retina and Macula @ Eye Physicians & Surgeons - Designed by Authentic Imaging