A most important source of eyestrain is in our eyes themselves. A large number of us are short-sighted, long-sighted, or astigmatic. These conditions are caused by the shape of the eyeball.

Strabismus (also called cross-eyes and squint) is caused by an imbalance of the muscles of the eyes. Babies are apt to be cross-eyed, but they should begin to lose this tendency by the time they are three months old. Do not put off consulting a doctor if your child is crosseyed. His vision may be impaired unless he is given glasses. Sometimes these will correct the condition, but occasionally a fairly simple surgical operation is necessary.

Fortunately, short-sightedness, long-sightedness, and astigmatism are readily corrected by wearing the proper glasses. Even if your eyes have always been perfect, they tend to change as you get older, and they are then unable to adjust to anything close at hand. That is why you should have your eyes examined as soon as you find yourself holding things off at a distance in order to see them, or notice that you cannot see as well as you used to in a poor light. Always have an ophthalmologist (eye doctor) examine your eyes and prescribe the proper lenses. If an ophthalmologist is not available, an optometrist can examine your eyes and prescribe glasses, if they are needed.

For those who feel that ordinary glasses are a handicap, contact lenses should be discussed with an ophthalmologist.

It is most unwise to try to avoid wearing glasses by spending hours on various systems of exercises that have not as yet been scientifically proved effective. Exercising the eyes can help under some circumstances; in themselves, the exercises usually do no harm. Their main dangers are that they may be used when poor vision is due to some eye disease such as glaucoma; and that people who use the exercises fail to go to an ophthalmologist who might, in his examination, discover some illness that first reveals itself in the eyes. For example, popeyes—eyes that are prominent and staring—may mean an over-active thyroid gland that, unless corrected, may lead to serious damage of the heart.

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