What Is It?
The retina is the light-sensitive layer at the back of the eye that is responsible for vision. Blood circulation to most of the retina's surface is through only one artery and only one vein. If either blood vessel or one of their smaller branches is blocked, blood circulation to the retina can be significantly disrupted. The blockage is called an occlusion. When this happens, the eye typically loses vision, often suddenly. The condition is painless.
Retinal Artery Occlusion
In adults, there are two main reasons that the retina's artery would become blocked: a thrombus or an embolus.
Less often, a retinal artery occlusion may be caused by vasculitis (inflammation of the artery's wall), trauma, sickle cell disease, clotting disorders, oral contraceptives or damage from radiation treatments. Overall, retinal artery occlusion is a rare illness that is responsible for only one out of every 10,000 visits to ophthalmologists (physicians who specialize in eye problems) in the United States. The average person with the illness is between 50 and 70 years old and has a history of heart disease, high blood pressure or diabetes. In almost all cases, only one eye is affected.
In the past, retinal artery occlusion has not included diabetic retinopathy. However, in some respects, diabetic retinopathy (which is a common condition) can be thought of as an occlusive condition of the retinal blood vessels. In diabetic retinopathy, the blood vessels affected are much smaller than the arteries involved in classic retinal artery occlusion.
Retinal Vein Occlusion
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