A retinal vein occlusion is sometimes referred to as an “eye stroke.” It’s the blockage of one of the veins returning blood from your retina back to your heart. Your retina converts light and images into nerve signals and sends them to your brain via the optic nerve. Blockages from blood clots or fluid buildup in your retinal veins impairs your retina’s ability to filter light and your ability to see. The severity of vision loss depends on which vein is blocked.

There are two types of retinal veins. There’s one central vein and many smaller branch veins. Likewise, there are two types of retinal vein occlusion. There’s central retinal vein occlusion and branch retinal vein occlusion.

The primary symptom of retinal vein occlusion is a blurring or loss of vision that’s usually sudden in onset and generally in only one eye. If it isn’t treated, the blurring or loss of vision usually gets worse in hours or days. Sometimes, you’ll see dark spots or floaters, which are tiny clumps of cells or material floating in your eye. In severe cases, a blocked vein will build up pressure and cause pain in your eye.

It’s important to see your doctor right away if you have these symptoms because a retinal vein occlusion can lead to other health problems.

Retinal vein occlusions usually occur because your arteries harden and cause a clot, much like a stroke. Blockages are more common in people with narrowed or damaged blood vessels, or those with chronic conditions that cause them. Such diseases include:

  • atherosclerosis, which is a hardening of the arteries
  • glaucoma, which is optic nerve damage that’s usually caused by increased pressure
  • macular edema, which is fluid leakage into the macula, or the area of the retina that allows for sharp focus
  • diabetes
  • high blood pressure
  • high cholesterol
  • blood disorders that affect clotting
  • people over the age of 60
  • people who smoke

This disease is diagnosed with a comprehensive eye exam, including vision and pressure checks, and examining the surfaces and vessels of your eye. Other tests to diagnose retinal vein occlusion include:

  • optical coherence tomography, in which a high-definition image is taken of your retina
  • ophthalmoscopy, in which your retina is examined with an ophthalmoscope
  • fluorescein angiography, in which a dye is injected into your arm that then travels to your retinal veins to be photographed for blockages

Your doctor may also perform blood tests for diabetes, high cholesterol, and blood clotting disorders.

Blockages in your retinal veins can’t be removed. Treatment focuses on issues arising from the occlusion, such as:

  • laser therapy to reduce edema, or swelling caused by fluid leakage
  • drug injections of corticosteroids to reduce inflammation
  • a vitrectomy, which is the removal of all or part of the jelly-like tissue in your eye called the “vitreous humor”

This clinical trial shows that a combination of ranibizumab and aflibercept is effective in restoring vision in patients with macular edema due to a retinal vein occlusion.

The outlook for people with this condition depends on its severity. Many people will recover and regain most of their vision, however for some, vision may not return.

Those with other eye conditions or complications are less likely to recover fully. Work with your eye doctor to keep your eyes healthy. Regular checkups can help prevent further problems.

The condition will sometimes go away on its own and you can regain vision.

Because this disease occurs in veins, you can reduce your risk of it by protecting your blood vessels and maintaining healthy vascular tissue. Healthy lifestyle and dietary changes include:

  • exercising
  • losing weight if you’re overweight
  • maintaining a healthy weight
  • quitting smoking if you smoke
  • controlling diabetes if you have diabetes
  • reducing your blood pressure if you have high blood pressure
  • reducing your cholesterol if you have high cholesterol
  • taking aspirin or other blood thinners if recommended by your doctor

Getting regular eye exams will help your doctor detect and diagnose any eye diseases early on.