A retinal occlusion occurs when the circulation of a retinal vein becomes obstructed by an adjacent blood vessel. This results in the stoppage of blood flow, causing hemorrhages in the retina. The retinal veins are the small “pipes” in the retina that drain blood out of the retina, and back to the heart. The veins drain the blood out of the eye, while the retinal arteries are the small blood vessels that deliver the blood (from the heart) to the retina.

Types of Occlusion

Nonischemic (also called venous stasis retinopathy) occlusions are relatively benign and account for 75-80% of all cases. The body develops alternate pathways for blood vessels that may result in macular edema but rarely in neovascularization with its accompanying problems. Nonischemic (also called venous stasis retinopathy) occlusions are relatively benign and account for 75-80% of all cases. The body develops alternate pathways for blood vessels that may result in macular edema but rarely in neovascularization with its accompanying problems.

Ischemic (hemorrhagic retinopathy) means that there is an inadequate blood supply, resulting in a marked decrease in vision. Hemorrhagic retinopathy results in complications such as macular edema, macular ischemia, and neovascularization that can lead to blindness in two-thirds of people diagnosed with this disorder.