When there is a blockage of blood flow through the main retinal vein, a condition called Central Vein Occlusion occurs. This condition is usually associated with arteriosclerosis and hypertension (high blood pressure) and is found frequently in diabetic patients. The blockage of blood flow causes the pressure in the retinal veins to increase resulting in hemorrhage and swelling of the retina. Vision can be affected mildly or severely, especially if the central retina is involved.
Treatment may include laser and of injections of medicine into the eye to reduce the amount of hemorrhage and swelling. Lucentis (ranibizumab), Eylea (aflibercept), and Ozurdex (dexamethasone) are all FDA-approved for vein occlusions. Some ophthalmologists also use another anti-VEGF drug called Avastin (bevacizumab). This use of Avastin is “off label.” These anti-VEGF drugs are used to stop or slow down new vessel growth.
In some cases, new blood vessels are formed in the tissue that has been damaged. These new blood vessels (called neovascularization) are fragile and bleed easily, causing additional visual loss. Another late complication is Neovascular Glaucoma. In selected cases, laser and/or injection may be considered to prevent or control these secondary complications.
If the blockage is only partial, vision may not be lost but may be decreased and will fluctuate from time to time. In these cases, treatment is directed toward easing the blood flow within the eye by using medicines that thin the blood.