What would happen if you misuse your eyes?

Good evening, everyone. Welcome to this lecture on reading hygiene. Perhaps you would ask what is reading hygiene? Well, hygiene tells us how to live comfortably and healthfully; it helps us to make the best use of our bodies. Reading hygiene, then, tells us how to make the use of our eyes—how to prevent eyestrain and how to read more comfortably.
    First and foremost, let us see what would happen if you misuse your eyes. When your eyes are not used properly, they let you know in various ways. Your eyes may hurt and your eyelids become red. You may not be able to see clearly. You may have headache, feel dizzy, or be uncomfortable in other ways. The human eye will stand hard use, but not abuse.
    Every day you have many opportunities to use your eyes wisely and well. Here are some good hints for good eye health that everyone can follow:
    Rest your eyes before they get tired. If you are reading for a long time, you can just close your eyes from time to time or look off at some distant objects. You will find that doing this relaxes your eye muscles, just as a good stretch relaxes your body.
    Never be careless about lighting. Do not read in either too dim a light or a glare. Be careful not to read in the twilight or in direct sunlight. Have the kind of light in which you see most clearly and comfortably.
    Hold the book at a distance from your eyes at which you can read most easily and comfortably. Many people read comfortably with the book about fourteen inches from their eyes. But each of us must find the distance that is best for him.
    Try not to read much while traveling on a moving train or bus. That causes eyestrain for many people. You can use the time doing other things, or thinking about what you’ve read.
    Your eyes are your most faithful servants. Like friends, if treated well, they will help you for many years.