- Central retinal vein occlusion (CRVO) is a blockage of the main vein that carries blood away from the retina in the back of the eye. It can lead to macular edema, a swelling of the retina that is a common source of vision loss. Studies suggest that inflammation might be a cause. Minocycline is a drug that might help prevent cells involved in inflammation from becoming activated. It is approved for use as an antibiotic, but it has not yet been tested to see if it can treat CRVO.