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Central Retinal Vein Occlusion

A central retinal vein occlusion is also known as a CRVO.

The entire body contains multiple arteries, which bring oxygenated blood circulation from the heart to all body organs and tissues as well as multiple veins that carry deoxygenated blood circulation back to the heart. Arteries and veins also play an important function in the eye.

A central retinal vein occlusion, or CRVO occurs in the main vein in the eye. When a CRVO occurs, there is reduced blood flow in the main vein causing the outflow of ocular blood circulation to be reduced, or to possibly stop altogether. When a CRVO occurs and the circulation is poor or absent, the blood flow is blocked, almost like a traffic jam. Blood and fluid may then leak out of the vein and cause macular swelling or edema causing vision loss.

What are the symptoms of a central retinal vein occlusion?

The symptoms of a central retinal vein occlusion, or CRVO most often occur in one eye. When experiencing a CRVO, a person may notice gradual or sudden vision loss in one eye. Central vision may be blurred or absent and floaters or dark spots may obscure vision. A blurry or dark area (scotoma) may affect the upper or lower margins of vision.

What are the causes and risk factors of a central retinal vein occlusion?

Sometimes, a central retinal vein occlusion happens spontaneously without cause. However, a blood clot, narrowed blood vessels, or high pressure in the eye caused by a thickened artery crossing over a vein (arteriosclerosis) may be the cause.

Artery walls may be compared to pipes as they are thicker and heavier. Vein walls can be compared to garden hoses as they are more flexible. When the artery hardens and presses on top of the vein, reduced blood circulation in the vein may occur causing poor or absent blood flow, thus causing a central retinal vein occlusion.


Risk Factors include:

  • High blood pressure
  • Diabetes
  • Glaucoma
  • Arteriosclerosis (hardening of the arteries)

To lower the risk for central retinal vein occlusion:

  • Eat a low-fat diet
  • Maintain an ideal body weight with BMI controlled
  • Maintain a weekly exercise regimen
  • Don’t smoke

What can I expect at a central retinal vein occlusion screening at Retinal Associates of Greater Philadelphia?

After a comprehensive, dilated eye examination is performed by the ophthalmologist, a series of diagnostic tests may be ordered to better evaluate the health of your retina. These tests include, but are not limited to:

  • Fundus Photography
  • Fundus Autofluorescence (FAF)
  • Optical Coherence Tomography (OCT)
  • Optical Coherence Tomography Angiography (OCT-A)
  • Intravenous Fluorescein Angiography (IVFA)

The physician may also order alternate tests to evaluate blood sugar levels as well as cholesterol levels to identify the cause of a central retinal vein occlusion.

How is a Central retinal vein occlusion treated?

There is no absolute cure for a central retinal vein occlusion. However, the retinal specialist will coordinate a plan of care with the primary care provider, or referring physician to aid in the diagnose and cause of the vein occlusion. The arteries and veins have a circuit throughout the entire body. If there is concern in the eye, there may be concern for overall health of the body. Therefore, a work up of body systems may benefit overall health as well as eye health.