If you look at a clear blue sky or a white background, you may see gray spots drifting across your vision. When you move your eyes rapidly, the spots move quite swiftly. When you try to focus on them, they appear a float slowly across the eyeball. That is why these moving shadows, cast on the retina are usually known as floaters.
They are a minor nuisance, but fortunately are normal and quite harmless. The shadows comes from tiny bits of tissue or debris in the vitreous humor, a jellylike and transparent part of the eye which lies behind the lens.
Some people who suddenly notice floaters in their field of vision believe they have detached retina. If the spots appear in a cloud like mass and are accompanied by flashing lights or dramatic sparks, that may indeed be so, Anybody with these symptoms should see an ophthalmologist as soon as possible.
The retina is a light-sensitive membrane lining the inside of the back of the eye. In many ways it resembles the film in a camera. The cornea and the lens cast images on the retina. Special nerve cells convert light into impulses that are carried via the optic nerve to the brain. Some parts of the retina away from the back of the eye. More often, a detached retina follows a tar or split in the retina. This may come through degeneration, which often makes the membrane thinner. Short-sighted people and those who have had cataract surgery commonly suffer the condition. A detached retina causes no pain, and sometimes a victim may be unaware of it until a dark curtain obscures vision in the affected eye. Fortunately, surgery for a detached retina today has a high rate of success but, as with many afflictions, swift attention improves a victim’s chances.