Central Retinal Vein Occlusion (CRVO)


Arteries and veins carry blood throughout your body, including your eyes. The eye’s retina has one main artery and one main vein. When the main retinal vein becomes blocked, it is called central retinal vein occlusion (CRVO).

When the vein is blocked, blood and fluid spills out into the retina. The macula can swell from this fluid, affecting your central vision. Eventually, without blood circulation, nerve cells in the eye can die and you can lose more vision.


What are symptoms of CRVO?

The most common symptom of CRVO is vision loss or blurry vision in part or all of one eye. It can happen suddenly or become worse over several hours or days. Sometimes, you can lose all vision suddenly.

You may notice floaters. These are dark spots, lines or squiggles in your vision. These are shadows from tiny clumps of blood leaking into the vitreous from retinal vessels.

In some more severe cases of CRVO, you may feel pain and pressure in the affected eye.

CRVO almost always happens only in one eye.

Who is at risk for CRVO?

CRVO usually happens in people who are aged 50 and older.

People who have the following health problems have a greater risk of CRVO:

  • high blood pressure
  • diabetes
  • glaucoma
  • hardening of the arteries (called arteriosclerosis)

To lower your risk for CRVO, you should do the following:

  • eat a low-fat diet
  • get regular exercise
  • maintain an ideal weight
  • don’t smoke

What causes CRVO?

CRVO happens when a blood clot blocks the flow of blood through the retina’s main vein. Disease can make the walls of your arteries more narrow, which can lead to CRVO. 

How is CRVO treated?

The blocked vein in CRVO cannot be unblocked. The main goal of treatment is to keep your vision stable. This is usually done by sealing off any leaking blood vessels in the retina. This helps prevent further swelling of the macula.

Your ophthalmologist may treat your CRVO with medication injections in the eye called “anti-VEGF injections.” The medicine can help reduce the swelling of he macula. Sometimes steroid medicine may be injected into the eye to help treat the swelling.

If your CRVO is very severe, your ophthalmologist may do a form of laser surgery. This is called panretinal photocoagulation (PRP). A laser is used to make tiny burns to areas of the retina. This helps lower the chance of bleeding in the eye and keeps eye pressure from rising too much.

It usually takes a few months after treatment before you notice your vision improving. While most people see some improvement in their vision, some people won’t have any improvement.