Retinal artery occlusions are caused by blockages in the retinal arteries. The blockage can occur in the form of a blood clot or thrombus but can also be caused by a piece of clot that breaks off (embolus) from another major artery in the body and lodges in a retinal artery. As soon as a retinal artery becomes blocked, there is rapid loss of vision in the area of retina served by the artery. In cases involving the central retinal artery (the main artery supplying the entire retina), severe and sudden vision loss occurs. Without treatment, irreversible vision loss occurs after about 90 minutes. One of the key risk factors for retinal artery blockage is arteriosclerosis (hardening of the arteries).

Central Retinal Artery Occlusion

Branch Artery Occlusion with Embolus

How are retinal artery occlusions treated?

Unfortunately, there is no proven treatment yet. In many instances, an attempt is made to abruptly lower the eye pressure by removing a small amount of fluid from the eye in hopes of dislodging the clot, but it is rarely successful. Attempts to use laser to break up the clot have had very limited success, with the exception of a few case reports. One investigational method involves using systemic medication to dissolve the clot, but this medication must be delivered with an invasive catheter threaded through major arteries in the head and neck and is not without the risk of causing stroke and bleeding in the brain. When a retinal artery occlusion is detected, a careful systemic vascular evaluation is recommended.