Retinal vein occlusion is the blocking of veins in the retina, the tissue at the back of the eyeball that turns light into signals that are sent to the brain via the optic nerve. The blockage can affect either the main vein (central retinal vein occlusion) or one of the small branches attached to the main vein (branch retinal vein occlusion).
The blockage prevents blood from leaving the retina. Symptoms of retinal vein occlusion include blurred vision, cloudy or spotted vision, and eye pain.
People with conditions that affect blood vessels, such as high blood pressure, leukemia, and diabetes, are at risk of developing retinal vein occlusion, as are people who smoke, are overweight, or have experienced eye trauma. There is no known cure for retinal vein occlusion. Treatments such as laser surgery and intraocular injections reduce fluid leakage to improve vision.