The eye is often compared to a camera. The front of the eye contains a lens that focuses images on the inside of the back of the eye. This area, called the retina is covered with special nerve cells that react to light.
Nerve cells need a constant supply of blood to deliver oxygen and nutrients. Most people understand what happens in a “stroke.” A small blood clot blocks the flow of blood through one of the arteries in the brain, and the area that is not getting blood becomes damaged. This same type of damage can happen anywhere in the body, not just the brain.
When the flow of blood from the retina is blocked, it is often because of a retinal vein occlusion. If this happens, the nerve cells of the retina can die and vision may be lost. Because all of the blood from the retina drains through one large vein, a blockage of that vein can affect all the vision in that eye.
Why does this happen?
Retinal vein occlusion happens when a blood clot blocks the vein. Sometimes it happens because the veins of the eye are too narrow. It is more likely to occur in people with diabetes, and possibly high blood pressure, high cholesterol levels, or other health problems that affect blood flow.