Because it's such a gradual process, people frequently don't realize how bad their sight has become. Eventually grandpa will back into somebody at a gas station, or inadvertently run off the road, and his insurance company will permanently sideline him. Losing one's driving privileges can be very traumatic - especially for someone who has been behind the wheel a long time. Elderly people can become withdrawn and severely depressed over losing their driving privileges. Fortunately, research shows that a simple dietary supplement, lutein, may prevent age-related macular degeneration.
Macular degeneration is, literally, degeneration of the spot.
In the case of the human eye, we're talking about a spot on the retina about the size of a pencil eraser. The retina is the part of the eye where all the action is. A layer of cells on the inside of the eyeball, the retina is actually an extension of the brain. It is composed of nerve cells that connect to the brain. Rods, which perceive light intensity, and cones which perceive color, are two types of nerve cells found in the retina.