Symptoms of CMV retinitis often appear relatively suddenly. They include general blurriness, seeing flashes or floaters, sudden loss of peripheral (side) vision, or blind spots in central vision. These symptoms all appear as the virus attacks the retina, the light-sensitive layer of nerves at the back of the eye. If left untreated, the virus can cause retinal detachment and will eventually destroy the retina and damage the optic nerve, causing permanent vision loss. Usually there is no pain felt as the retinal damage is taking place. Symptoms usually start in one eye and but can spread to the other eye as well.