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 primarily through one artery and 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.
If a main vessel becomes occluded, the eye typically loses vision, often suddenly. If blockage occurs in a smaller branch vessel, there may be partial vision loss or no symptoms. The condition is often painless.
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