Retinal Vein Occlusion (RVO) is blockage of the small veins that carry blood away from the retina. These small veins cleanse and nourish the retina. The retina is the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain. Retinal vein occlusion is most often caused by hardening of the arteries, known as atherosclerosis, and the formation of a blood clot.
There are two types of retinal vein occlusion. Central retinal vein occlusion (CRVO) is obstruction of the retinal vein at the optic nerve while branch retinal vein occlusion (BRVO) is obstruction at a branch of the retinal vein. BRVO often occurs when retinal arteries that have been thickened or hardened by atherosclerosis cross over and place pressure on a retinal vein.
Risk Factors for Retinal Vein Occlusion Include:
- Atherosclerosis, which can be caused by smoking
- High blood pressure (hypertension)
- Cardiovascular disease
- Other eye conditions, such as glaucoma, macular edema, or vitreous hemorrhage
Retinal vein occlusion most often occurs in older patients. People who maintain a healthy lifestyle of eating a low-fat diet, getting regular exercise and not smoking are less likely to develop this condition. Blockage of the retinal veins may cause other eye problems including:
- Macular Edema (swelling of the central retina)
- Sudden blurring or vision loss in all or part of one eye
- Sudden appearance of floating spots or flashing lights
Many people will regain vision, even without treatment. However, vision rarely returns to normal. There is no way to reverse or open the blockage. After the first few months, it may be useful to do a fluorescein angiogram. This test is helpful in analyzing the retinal vessels, particularly the capillaries which may manifest abnormalities. You may need treatment to prevent another blockage from forming in the same eye or the other eye. It is important to control and manage diabetes, high blood pressure, and high cholesterol levels.
Treatment for the complications of retinal vein occlusion may include:
- Focal laser treatment, if macular edema is present
- Intravitreal injections of anti-vascular endothelial growth
- Laser treatment to prevent the growth of new, abnormal blood
vessels that may lead to glaucoma