Retinal artery occlusion is a blockage in one of the small arteries that carry blood to the retina—the layer of tissue in the back of the eye that senses light. Retinal arteries may become blocked by a blood clot or fat deposits that get stuck in the arteries. These blockages are more likely if there is any hardening of the arteries (atherosclerosis) in the eye.
Clots may travel from other parts of the body and block an artery in the retina. The most common sources of clots are the carotid artery in the neck and the heart. Most clots occur in people with carotid artery disease, diabetes, atrial fibrillation or heart valve problems, hyperlipidemia, high blood pressure, intravenous drug abuse or damage to arteries due to an immune response.
If a branch of the retinal artery is blocked, part of the retina will not receive enough blood and oxygen. If this happens, you may lose part of your vision. Symptoms of branch retinal artery occlusion include the sudden blurring or loss of vision in all of one eye (central retinal artery occlusion or CRAO), or only in part of one eye (branch retinal artery occlusion or BRAO). The retinal artery occlusion may last for only a few seconds or minutes, or it may be permanent. If the blood clot moves to another part of the brain, symptoms of a stroke may develop.