Retinal arteries and veins can become blocked by a blood clot or substances (such as fat or plaque) that get stuck in the blood vessels. This is usually caused by an underlying disorder such as glaucoma, hypertension, diabetes, coagulation disorders, atherosclerosis, or hyperlipidemia. Vision loss after retinal vein occlusion varies. Hemorrhage (bleeding) may be present, and the person may be at risk for developing glaucoma. However, in retinal artery occlusions, there is considerable visual loss. The degree of loss is partly related to the location of the occlusion. People with retinal vessel occlusion have a risk of stroke because the source of the clots (emboli) affecting the eye could also send clots to the brain. Retinal vessel occlusion more frequently affects older people. Risk factors are related to the possible disorders that cause the blockage.
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