Retinal arteries and veins can become blocked by a blood clot, fat deposit, or a fragment of atherosclerotic plaque. This is usually caused by an underlying disorder such as glaucoma, hypertension, diabetes, coagulation disorders, atherosclerosis, or hyperlipidemia.

The vision loss after retinal vein occlusion is variable. Hemorrhage may be present, and the person may be at risk for developing glaucoma. In retinal artery occlusions, there is a profound visual loss. The degree of loss is, in part, related to the location of the occlusion. There is a risk of stroke because the source of the clots (emboli) affecting the eye could also send emboli to the brain.

Risk factors are related to the possible underlying disorders. Medical attention should be sought to determine if other health problems exist. The condition affects older people more frequently.