The retina is fed by the blood flow of oxygen and nutrients from the veins. When there is a blockage in the branch veins of the retina, there can be branch veinous occlusion of the retina (BRVO).
BRVO is a blockage in the small capillaries in the retina. When the main vein of the retina is blocked, this is called central retinal veinous occlusion or CRVO.
The most common symptom of BRVO is blurring or loss of vision on the whole or a part of one eye. Blurring or loss of vision is painless and can develop over a few hours or days. Sometimes there is full and sudden loss in vision. BRVO almost always develops in one eye only.