The retinal vein carries blood away from the retina, so when the vein is blocked, blood flow backs up and can cause bleeding (hemorrhages) and swelling in the retina. Retinal vein occlusions can also present as gradual or sudden and painless vision loss that ranges from mild to severe. Not everyone has symptoms, but symptoms may include blurry vision, loss of vision, or dark spots in or floating in the vision. Risk factors for this type of occlusion include diabetes, high blood pressure, smoking, glaucoma, and other blood clotting disorders.

Depending on the severity and location of the occlusion, treatment may include close monitoring, injected medications, or laser treatment to the eye. With treatment, many patients retain good vision.