Why do some people need glasses and others don't?
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
How Eyes Work
The eyeball includes the
-nee-uh), clear tissue that helps the eye focus; the
, the colored part; the
, which lets light into the eye; and the
, 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 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
will interpret the image, and the more likely you will see the
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?
are common refractive problems. It's easy to get the two
means the person can see stuff that's near, like a book, but
has trouble seeing stuff that's far away.
means the person 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
Another refractive problem is called
-muh-tih-zum). 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 another person. You know this if
you've ever tried on someone else's glasses!
If you need glasses or contact lenses, your doctor will write
down your 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 having trouble with your vision, your mom or dad
can take you for an eye exam. This might happen as part of your
regular checkup at the doctor. But you need to see a vision
specialist if your parents or your doctor think you might need
You might see an ophthalmologist, optometrist, or an optician.
What's the difference? An ophthalmologist is a doctor trained
to treat vision problems who may also do eye surgery.
An optometrist is a licensed professional who specializes in eye
exams and in figuring out the right prescriptions for eyeglasses
and contact lenses. Opticians make or sell eyeglasses and contact
lenses according to an ophthalmologist's or optometrist's
At your eye exam, you'll probably be asked to read from an
eye chart. This is the chart with letters in different sizes. You
also might be asked to look at some text up close, like reading
from a book. These tests measure how well you see from close and
from far away.
If you need glasses or contact lenses, there's a special
gizmo that lets you try a few different prescriptions until you
find the one that gives you the clearest vision. It's kind of
like a big pair of glasses, but a bunch of different lenses can be
switched in and out really quickly.
The person doing your eye exam may switch between two different
lenses and say, "Like this or like this?" You'll have
to say which one looks clearest. If you're not sure, say so.
Remember, the idea is that you get the right prescription so your
vision will be top-notch!
The Fun Part
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 and plastic
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
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. Crunch!
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
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!
Sharon Lehman, MD
Date reviewed: December 2007
Originally reviewed by:
Alexander E. Pogrebniak, MD
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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