BRAO blocks the small arteries in the retina, the light- sensing nerve layer lining the back of the eye. The most common cause of BRAO is a thrombosis, the formation of a blood clot. Sometimes the blockage is caused by an embolus, a clot carried by the blood from another part of the body.
Central vision is lost suddenly if the blocked retinal artery is one that nourishes the macula which is the part of the retina responsible for fine sharp vision. Following BRAO, vision can range from normal (20/20) to barely detecting hand movement. BRAO poses significant risks to vision. If you have had a BRAO or have high blood pressure, regular visits to your ophthalmologist are essential.