Color vision deficiency (also called color blindness) is a vision disorder in which a person…
The retina (the light-sensitive membrane lining the back of the eye) receives its blood supply from the central retinal artery, a tiny blood vessel that enters the back of the eye through the optic nerve. Sometimes, usually in middle-aged or older people, the central retinal artery or one of its branches becomes blocked, cutting off the blood supply to the retina. The blockage may be caused by a thrombus (blood clot) or by an embolus (a tiny fragment of a blood clot or fatty deposit) that has traveled to the artery from the heart or from a blood vessel elsewhere in the body.
In rare cases, it may be possible to restore some of the lost vision by causing the clot or embolus to move farther along the blood vessel to a position where less of the retina is affected. This may be done by reducing pressure inside the eye, either with medication or by draining excess fluid, within a few hours of the appearance of symptoms.