A retinal artery occlusion occurs when the central retinal artery or one of the arteries that branch off of it becomes blocked.  This blockage is typically caused by a tiny embolus (blood clot) in the blood stream. The occlusion decreases the oxygen supply to the area of the retina nourished by the affected artery, causing permanent vision loss. Retinal artery obstruction is like a stroke in the eye. the damage can be relatively mild or quite severe, depending on the extent to which the blood flow has been disrupted.
Treatments to improve vision in retinal artery occlusion can work only if the patient can reach the OT within an hour of the incident.. Some patients experience a substantial improvement in vision that usually occurs in the first few hours or days after onset of the symptoms.
It is extremely important that the eye care is closely followed after a retinal artery obstruction. An uncommon but significant complication is the development of a severe form of glaucoma, which can completely eliminate vision and cause the eye to be red and painful. Laser treatment can be used to reduce the glaucoma, though it does not improve vision. Newer treatments like intravitreal injections are helpful in the management of neovascular glaucoma.
Any patient with CRAO or BRAO should have a medical evaluation to look for source of embolism. Often the blockage is the result of hardening or cholesterol deposition in  the arteries, with a fragment of cholesterol or a clot breaking off from a large blood vessel and floating to eventually obstruct a smaller blood vessel in the eye. An evaluation by a cardiologist is usually quite helpful in identifying the source of the obstruction. It may be necessary to undergo blood tests or other diagnostic tests such as ultrasound of the heart and neck. Sometimes anticlotting agents are helpful in preventing future blockages. Though these medications will not improve the sight in your affected eye, they may have a long-term benefit for you.
If a patient experiences any marked decrease in vision, or if the eye becomes painful, see your doctor immediately. Otherwise, keep to scheduled appointments.