A Guide to Central Retinal Vein Occlusion (CRVO)

Medically Reviewed By Katherine E. Duncan, MD

Central retinal vein occlusion (CRVO) is a blockage or reduction in blood flow out of the main vein of the eye’s retina. CRVO can sometimes lead to vision loss. However, treatment can help protect your vision.  The retina is a light-sensitive layer of tissue at the back of the eye. It transmits light and visual information to the brain via electrical signals, helping to produce vision.

CRVO occurs when the central retinal vein is blocked or has reduced blood flow from the eye. The central retinal vein is the main blood vessel that helps blood flow away from the retina.

Key facts about central retinal vein occlusion (CRVO)

  • CRVO is when the main vein of the retina is blocked or has reduced blood flow.
  • You may not experience noticeable symptoms with mild CRVO. You later might develop blurry vision or eye irritation.
  • Researchers are trying to find the cause of CRVO. However, specific health conditions may increase the risk of CRVO.
  • Treatment options such as injected medications and laser therapy may help protect your vision and slow the condition’s progress.

Central retinal vein occlusion types

An eye doctor uses a slit lamp to look into someones eyes.
Sean Locke/Stocksy United

CRVO has two primary types Trusted Source National Eye Institute Governmental authority Go to source :

  • Non-ischemic CRVO: This causes blood vessels in the retina to leak. It’s usually milder than other CRVO cases, but without treatment, it can become severe. Non-ischemic CRVO is also more common than ischemic CRVO.
  • Ischemic CRVO: This is when blood flow to the vessels in the retina is blocked or reduced. Generally, it is more severe than non-ischemic CRVO.

Branch retinal vein occlusion (BRVO) is another type of retinal vein occlusion. BRVO affects the smaller retinal veins instead of the main central retinal vein affected by CRVO.

CRVO also differs from central retinal artery occlusion (CRAO). CRAO is a type of stroke that affects the retina’s main artery — the type of blood vessel that takes blood to the retina. By contrast, CRVO affects the retina’s central vein — the blood vessel that takes blood away from the retina.

Central retinal vein occlusion symptoms

Mild CRVO may not cause noticeable symptoms until it progresses. However, many people develop blurry vision.

CRVO can also cause symptoms such as:

Vision loss and blurry vision may affect one section or all of your vision. They may develop suddenly or more slowly, over hours to days.

Some people also report that their symptoms come and go.

Central retinal vein occlusion causes and risk factors

Researchers are working to understand the exact cause of CRVO. However, experts know that CRVO develops due to reduced blood flow Trusted Source National Eye Institute Governmental authority Go to source in the central retinal vein. This sometimes occurs because of a blood clot.

Reduced blood flow and blood clots may mean blood and other substances leak into the retina, causing swelling and vision impairments. This swelling is called macular edema.

Read more about macular edema and its treatment.

If blood flow is severely reduced, the cells in the retina cannot receive enough oxygen. A lack of oxygen can damage the cells, further affecting vision.

Reduced blood flow can also trigger neovascularization, the growth of new, fragile blood vessels in the retina. These blood vessels may also leak blood and fluids, causing more damage.

Factors that may increase the risk of developing CRVO include:

  • being age 50 or older
  • smoking
  • having any of the following health conditions:
    • diabetes

When to see a doctor

Contact an eye doctor promptly if you notice new, persistent, or concerning eye symptoms.

Some eye symptoms may need emergency care. Call 911 or your local emergency services for any of the following symptoms:

Routine eye checkups are essential to protect your eye vision and eye health. Many eye conditions don’t cause Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source noticeable symptoms until they are severe.

Talk with an eye doctor about how often you should have a comprehensive exam. Recommendations can vary per person, depending on your age, health, and ethnicity.

For example, the Centers for Disease Control and Prevention (CDC) Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source recommends that people with diabetes get a dilated eye exam at least once a year.

Central retinal vein occlusion diagnosis

A comprehensive dilated eye exam is the primary method of diagnosing CRVO and ruling out other conditions. Also, an eye doctor may scan the retina to look for signs of swelling.

Other tests that can help diagnose CRVO include:

Doctors may also ask about your:

  • symptoms
  • medical history
  • family medical history

Central retinal vein occlusion treatment

The primary aim of CRVO treatment is to protect your vision by preventing further swelling and bleeding.

Treatment options include Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source :

  • Anti-VEGF medications: A doctor injects these medications into the eye to prevent and reduce swelling and bleeding. They can also help stop neovascularization.
  • Steroid medications: Steroid injections may help reduce swelling.
  • Laser therapy: Panretinal photocoagulation (PRP) uses a laser to make tiny, deliberate burns in the retina. This can help stop bleeding and prevent pressure in the eye from increasing too much. Doctors may recommend PRP only for severe CRVO.
  • Vitrectomy: Vitrectomy Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source surgery allows doctors to remove blood and other debris that may have developed due to CRVO.

Learn more about injections for macular edema and vitrectomy surgery.

Central retinal vein occlusion prevention and management

Experts do not know the cause of CRVO, and there are no specific ways to prevent it. 

However, the following steps may help lower your risk of CRVO and support your overall eye health:

  • following your doctor’s recommendations for any health conditions you have
  • avoiding smoking or using tobacco
  • getting regular physical activity
  • maintaining a moderate weight
  • eating a balanced diet as recommended by a doctor or registered dietitian

Nutritional needs can vary per person, but a balanced diet that supports eye health typically includes:

  • eating a variety of fruits and vegetables
  • prioritizing whole grains, lean proteins, and oily fish
  • limiting your intake of:
    • sodium or salt
    • added sugar
    • saturated fats
    • refined grains, such as white bread, rice, and pasta

Learn more about nutrients to include and vision loss prevention.

Central retinal vein occlusion outlook

The outlook of CRVO can vary from person to person. 

A 2023 review Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source suggests that CRVO may have better outcomes in younger people.

In some cases, CRVO may improve without treatment, whereas in others, it may worsen. 

CRVO can also lead to permanent vision loss. Most often, vision impairments with CRVO occur due to developing chronic macular edema.

However, early and effective treatment can help prevent or stop vision loss.

Talk with a doctor for personalized advice about your outlook and treatment.

Find more support for blindness and vision loss.

Summary

CRVO is when the main vein of the retina becomes blocked, causing swelling and eye damage.

Researchers do not yet know the cause of CRVO. However, health conditions such as diabetes and high blood pressure may raise your risks.

As CRVO and other eye conditions may not initially cause symptoms, regular eye checkups protect your vision.

Talk with a doctor as soon as possible if you notice any eye symptoms or have questions about CRVO.

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Medical Reviewer: Katherine E. Duncan, MD
Last Review Date: 2024 May 10
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