What is RVO?
The eye has arteries which bring oxygenated blood into the retina, and veins which take the deoxygenated blood back to the heart. When the blood flow in a retinal vein is blocked, this is called a retinal vein occlusion. Due to the backpressure, the veins leak blood and fluids into the retina, causing swelling (i.e. edema). The blockage can also result in decreased retinal circulation. Sometimes, when there is a severe decrease in the circulation, new leaking blood vessels can form not only in the retina, but within the iris, which is in the front of the eye. This can cause painful, elevated pressure in your eye.
CRVO
CRVO (central retinal vein occlusion) is when the main vein is blocked by a blood clot. Typically, this is the more severe of the two conditions. There are numerous causes including inflammation, high cholesterol, poor general circulation and even an abnormality in one or more of the blood clotting factors. Often there is no known cause.
BRVO
BRVO (branch retinal vein occlusion) is when a small blood vessel attached to the main vein becomes blocked. The most common cause for this is hypertension, and the damage usually occurs where a retinal artery and vein cross over one another. It typically only causes damage to less than half the visual field.
These are chronic conditions which need to be managed. Every patient is different and may require one or more types of treatment, and sometimes no treatment at all apart from monitoring their cardiovascular health. Laser treatment is done less frequently now that intravitreal medications can be injected. Anti – Vascular Endothelial Growth Factor (anti-VEGF) medications, which include Lucentis, Avastin and Eylea, can be administered on a monthly or less frequent basis. Steroids such as Ozurdex and Triesence can also be injected on a periodic basis. Treatment may last only a few months but can sometimes be necessary for years.