Glasses and Contact Lenses

Why do some people need glasses and others don't?
Everyone's eyes are a little different — not just the color, but the way they work and how well they see. Sometimes all the parts of the eye don't work together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most people see more clearly.

How Eyes Work

The eyeball includes the cornea, clear tissue that helps the eye focus; the iris, the colored part; the pupil, which lets light into the eye; the lens, which also helps the eye focus; and the retina, at the very back of the eye.
When all of the eyes' parts are working properly, a kid doesn't have vision problems. You can see because your eyes capture an image like a camera and send that image to your brain, where it can be interpreted. For instance, if there's an elephant in front of you, almost instantly, your brain says, "Hey, that's an elephant."
Your eyes need to bend light rays so the image can be focused sharply on your retina. The better your retina records the image, the more likely that your brain will interpret the image, and the more likely you will see the image clearly.
Refracting is a big word that means bending light rays. If a person has vision trouble, it's often a refractive problem. Glasses or contact lenses work so well because they can correct refractive problems. In other words, they bend the light rays in a way that lets you see more clearly.
Laser surgery also can correct some vision problems, but it's not recommended for kids because they're still growing.

Nearsighted and Farsighted — Which Is Which?

Nearsightedness and farsightedness are common refractive problems. It's easy to get the two confused:

• Nearsighted means someone can see stuff that's near, like a book, but has trouble seeing stuff that's far away.
• Farsighted means someone can see stuff that's far away, but has trouble seeing up close, like reading the print in a book.

In both cases, the image is not properly focused on the retina. With nearsightedness, the image becomes focused in front of the retina. With farsightedness, the image is focused behind the retina. The shape of a person's eyeballs also can cause refractive problems.
Another refractive problem is called astigmatism. This means that the cornea is an uneven shape, and it bends the light in different directions. This can distort what a person sees and make things look blurry.
Glasses or contact lenses correct vision because they allow the eye to focus light in the right spot on the retina — the spot that produces the clearest image. Because everyone's eyes are different, a pair of glasses that makes one person see wonderfully may look terribly blurry to someone else. You know this if you've ever tried on somebody else's glasses!
If you need glasses or contact lenses, your doctor will write you a prescription. In this case, a prescription doesn't mean medicine you'll pick up at the drugstore. A vision prescription is a piece of paper with numbers on it. The people who will make your glasses for you need these numbers to create lenses that will correct the way your eye bends light. Remember, the target is right in the center of the retina.

If you're going to get glasses, it's time to pick frames. It can be fun to try these on. Choose ones that are comfortable and sturdy. But also make sure you like them — you'll be wearing them a lot!
The lenses themselves can be made of different materials, such as safety glass or shatterproof plastic (polycarbonate). Because glass tends to be heavy and it may shatter, most glasses today are made of polycarbonate plastic. If you play sports, you may want to ask about special eyewear you can wear on the field.
Glass tends to be heavy and it can shatter. Plastic scratches easily, but it's often the best choice for kids. If you play sports, you may want to ask about eyewear you can wear on the field.
With glasses, you'll also want to find out how to clean them properly. And it helps if you have a glasses case and put them in it when you're not wearing them. The last thing you want is to sit on your new glasses.
If you're going to get contact lenses, you'll get some advice from the ophthalmologist or optician about which kind will be best for you. Some are disposable and others need to be cleaned. When you learn which type you're going to get, you can start becoming an expert in how to wear them safely and keeping them clean. The most important thing about contact lenses is good hygiene to prevent infections in your eye.
But the really fun part of new glasses or contact lenses is how well you can see. They can make your whole world look better!