Most people know that high blood pressure and other vascular (blood vessel) diseases pose risks to overall health, but many may not know that high blood pressure can affect vision by damaging the arteries in the eye.
Central retinal artery occlusion (CRAO) is a disease of the retina. The retina is a layer of light-sensing cells lining the back of your eye. This condition nearly always damages a portion of the retina called the macula, which is located in the center of the retina and enables you to see fine details clearly. You rely on your macula whenever you read, drive, or do other activities that require you to focus on fine details.
CRAO blocks the central artery in your retina, and is often called a stroke of the retina or a stroke of the eye. The first sign of CRAO is a sudden and painless loss of vision that leaves you barely able to count fingers or determine light from dark.
Loss of vision can be permanent without immediate treatment. Irreversible retinal damage occurs after 90 minutes, but even 24 hours after symptoms begin, vision can still be saved. The goal of emergency treatment is to restore retinal blood flow. If you have signs or symptoms of a CRAO, call 9-1-1 immediately. After emergency treatment, you should have a thorough medical evaluation.
CRAO usually occurs in people between the ages of 50 and 70. The most common medical problem associated with CRAO is arteriosclerosis or atherosclerosis (hardening of the arteries). Carotid artery disease is found in almost half the people with CRAO.
The most common cause of CRAO is a thrombosis (an abnormal blood clot formation). CRAO can also be caused by an embolus, a clot that breaks off from another area of the body and is carried to the retina by the bloodstream.
If you have had a CRAO, regular visits to your eye doctor are essential to protect vision. Be sure to discuss your options with your eye doctor.