What is a Retinal Vein Occlusion (RVO)?
A RVO is a blockage of the major vein that drains blood from the retina. This can be caused by a blood clot or fluid build up in the vein. It may lead to varying degrees of vision loss, depending on the severity and location of the blockage. It affects about 1 to 2% of people over 40, although most cases occur in people over 60. Although the amount of vision loss can be significant, especially if it affects the central part of the retina (macula), this disease will not cause total or black blindness. It usually only occurs in one eye, although about 10% of people with RVO will eventually develop the problem in the other eye.
There are two types of retinal vein occlusion: Central retinal vein occlusion (CRVO) is the blockage of the main retinal vein. Branch retinal vein occlusion (BRVO) is the blockage of one of the smaller branch veins.
Causes and Symptoms:
A RVO is usually caused by hardening of the arteries which compress the underlying vein. Hypertension, diabetes, high cholesterol and/or smoking contribute to hardening of the arteries. Glaucoma can also predispose an individual to the development of a RVO. A RVO causes fairly sudden, painless, blurred vision usually in one eye.
There are two reasons why people with a RVO may require treatment. The most common reason is swelling in the macula. Less common is the growth of abnormal blood vessels on the retina, optic nerve or iris that may cause bleeding within the eye or a dangerous increase in the pressure within the eye. Swelling within the macula is treated with intravitreal injections of medications such as Lucentis, Avastin, Eylea,or steroids into the eye. Abnormal blood vessels growing within the eye are treated with retinal laser and occasionally with injections.