Blockage of central retinal arteries and branch retinal arteries

[Agnes]

An artery in the retina (the transparent, light-sensitive structure at the back of the eye) may become blocked, causing sudden, painless loss of vision.

Doctors typically make the diagnosis by looking in the eye with an ophthalmoscope and sometimes by testing.
Treatments are usually unsuccessful in restoring vision.

The central retinal artery is the main vessel that supplies blood to the retina. This artery can become completely blocked by an embolism or thrombosis (formation of a blood clot in the artery). Blockage may occur in the main artery or in its branches.
An embolism is a collection of solid material that floats in the bloodstream until it gets stuck in and blocks a blood vessel. The material that forms an embolus can come from a piece of atherosclerotic plaque, fat, infected material from an infected heart valve (endocarditis), or a noncancerous (benign) tumor in a heart chamber (atrial myxoma).
Giant cell arteritis, an inflammation of the blood vessels, is also a possible cause of retinal artery blockage.
Sometimes the cause of the blockage is unknown.