Central retinal artery occlusion

Central retinal artery occlusion (CRAO) is a disease of the eye where the flow of blood through the central retinal artery is blocked (occluded). There are several different causes of this occlusion; the most common is carotid artery atherosclerosis.

Central retinal artery occlusions cause sudden, acute, and painless loss of vision in one eye. Fundoscopic exam will show a red lesion, called a "cherry red spot," with surrounding pale retina (the pale color is caused by ischemia of the retina).

The ophthalmic artery branches off into the central retinal artery which travels with the optic nerve until it enters the eye. This central retinal artery provides nutrients to the retina of the eye, more specifically the inner retina and the surface of the optic nerve. Variations, such as branch retinal artery occlusion, can also occur. Some people have cilioretinal arterial branches, which may or may not be included in the blocked portion.

Risk factors for CRAO include the following: being between 60 and 65 years of age, being over the age of 40, male gender, hypertension, caucasian, smoking and diabetes mellitus. Additional risk factors include endocarditis, atrial myxoma, inflammatory diseases of the blood vessels, and predisposition to forming blood clots.

The most common cause for CRAO is carotid artery atherosclerosis. In patients of 70 years of age and older, giant cell arteritis is more likely to be the cause than in younger patients. Other causes can include dissecting aneurysms and arterial spasms.

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