The front of the eye contains a lens that focuses the images on the inside of the back of the eye. This area is the retina. The retina is where the eye focuses the images we see. It is covered with special nerve cells that convert light into signals sent through the optic nerve to the brain, where they are recognized as images. The conditions affecting the retina affect the ability to see.
The arteries carry blood from the heart to other parts of the body, and the veins carry the blood back to the heart. An obstruction in an artery or vein is called an occlusion or stroke. When blood flow from the retina is blocked, it is often because a clot blocks retinal vein. This condition is called retinal vein occlusion.
Nerve cells need a constant supply of blood to provide oxygen and nutrients. Blood vessels provide this supply. In a stroke, a small blood clot blocks the flow of blood through one of the arteries of the brain, and the area that does not take blood is damaged.
This same type of damage can occur anywhere on the body. When a vein of the retina is blocked, it cannot drain blood from the retina. This leads to hemorrhages and leakage of fluid from the blocked blood vessels.
There are two types of retinal vein occlusion:
Obstruction of the vein of retinal vein occurs 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.
Symptoms of retinal vein occlusion range from subtle to very obvious. There is painless blurring or loss of vision. It almost always happens to a single eye. At first, blurring or loss of vision may be slight, but it gets worse overthe next few hours or days. Sometimes there is complete loss of vision almost immediately.
If these symptoms occur, it is important to schedule an appointment with your doctor as soon as possible. Retinal vein occlusion often causes permanent damage to the retina and loss of vision.
Unfortunately, there is no way actually to unblock the retinal veins. However, your doctor may treat any health problems that appear to be related to retinal vein occlusion.
Vision may return to some eyes that have had retinal vein occlusion. About 1/3 has some improvement, about 1/3 remains the same, and about 1/3 gradually improves, but it may take a year or more to find out the final result. In some cases, blocked vessels will lead to fluid accumulation in the retina. In others, they can provoke the formation of new blood vessels.
Return visits are recommended to monitor the progression of your disease. It is important to detect changes in your condition and formulate treatment plans as needed. It is also important to tell your primary care doctor about the obstruction of the vein of the retina so that he can evaluate and treat any underlying systemic diseases.