Have you ever wondered whether there's any truth in some of the stuff you may have been told about how to treat your eyes?For example, you may have been concern that sitting too close to the TV or computer can ruin your eyes. But actually that's wrong. You may also have heard that using a night-light (instead of bright light) to read will cause shortsightedness, but there's no clear scientific evidence to support this idea. You can't strain your eyes in low light when you read.
So what's the reason of many common vision harms?Often, eye shape is the culprit. Someone with perfect 20/20 vision has eyes that are principally round like a baseball. Someone who needs corrective lenses to see usually has eyes that are shaped in a different way.
Myopia or nearsightedness is one of the most common troubles teens have with their eyes. When a teen has myopia, he or she is powerless to focus correctly on things that are far away. People with myopia have eyes that are a little longer than normal, measuring from the front of the eyeball to the back. This extra length earnings that light focuses in front of the retina instead of on it, and that affects vision. Glasses or contacts can easily correct this problem.
Hyperopia or farsightedness, is another problem. People with hyperopia have difficulty focusing on things close up because their eyes are too "short"from front to back. In people with hyperopia, light focuses behind the retina instead of on it, causing shadowy vision. Someone with momentous foresight will need glasses to correct his or her vision. But here's an interesting fact: Many babies are born farsighted! Their eyeballs get longer as they grow, and most of them outgrow the condition.
Another condition where the eye is differently shaped is astigmatism. Here, the cornea isn't perfectly round. To be able to see well — either close up or far away — the person needs contact lenses or glasses.
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