The retina is the light sensing tissue at the back of our eye. The veins drain blood out of the retina and return it to the heart. Blockage or occlusion in the vein prevents adequate blood flow in the affected area. The walls of the vein leak blood and excess fluid into the retina. The main retinal vein is blocked.
Blood flow is poor throughout the entire retina.
The amount of visual loss varies in younger people but is often severe in older people. A smaller branch of the main retinal vein is blocked. Only the part of the retina drained by this branch vein is damaged. Blurred vision is the main symptom of retinal vein occlusion. It occurs when the excess fluid leaking from the vein collects in the macula.