This is one of the biggest myths, eye experts say. Sitting too close to the TV does not make vision worse.

Many eye conditions do not affect central (“seeing”) vision until late in the disease. Regular eye exams, especially if you have diabetes or a family history of eye disease, are important to find problems before your central vision is affected.

The eye is like a video camera; it adjusts to the light.

Eye care providers say that reading glasses purchased over the counter won't do any harm and may solve your problem, as long as that problem is simply the inability to read that often accompanies aging. If you have other problems, such as the inability to focus on distant objects, these glasses won't help. The experts advise you to get an eye exam when any vision problem appears.

You need sunglasses that block ultraviolet (UV) radiation. Dark sunglasses without UV protection may be dangerous, eye experts say. The pupil dilates to adjust to the lack of light, and this allows the eye to absorb rays that may lead to cataracts and could damage the retina.

But eyestrain is usually a combination of tension in the muscles and drying out of the surface of the eyes from staring and not blinking. When we work, we often furrow our brow, hold our heads tense, and stress neck muscles. We blink less often, so the eye surface dries out. To reduce strain, take a break every few minutes. Get your eyes off the screen and roll your head around a bit to stretch the muscles. You may want to use artificial tears if your eyes are very dry.

Eye exercises don't improve how well you see. Your vision—no matter how good or bad it may be—is likely inherited.

Many people have lost vision when hit by a nail deflected by an indirect blow from a hammer. You should wear goggles when using a hammer or other household tools, such as lawnmowers, drills, and jigsaws. Children should also wear safety goggles when mowing lawns or helping with carpentry work.

Some people show up at the eye care provider's office complaining that they just lost the sight in 1 eye, particularly if the cataract is worse in 1 eye. But changes from normal cataracts develop slowly over years. The patient unknowingly compensates with the better eye. They may not notice the slow decrease in vision or change in color perception until it is significant.