Have you ever wondered why some people seem to have eyes that don't look straight ahead? Maybe you've noticed that sometimes their eyes go in different directions when they're looking at an object or at you.

Let's find out why some eyes don't see straight and how kids with this problem get help to fix it.

Why Are Some Eyes Not Straight?

Strabismus (say: struh-biz-mus) is the term used for eyes that are not straight and do not focus on the same object. Eyes can turn in (toward the nose) or out (toward the ear) if the muscles that move the eyes do not work right or if the eyes are not able to focus properly. Strabismus is also sometimes called crossed eyes, when they turn in, or walleye, when they turn out. It affects about 4 out of every 100 kids in the United States.

You may have heard someone describe an eye that is not straight as a lazy eye, but that is not what lazy eye means. It means that a person's vision is weak or lazy. The medical term for lazy eye is amblyopia (say: am-blee-o-pee-uh).

Strabismus and amblyopia are closely related and often (but not always) occur together. Sometimes strabismus can cause amblyopia, and sometimes it's the other way around with amblyopia causing strabismus. When a kid has both conditions, it may be difficult to say which came first.

The Eyes Have It!

So what happens when a kid has an eye that isn't straight? To understand, first you need to know a little bit about the eye. The eye is like a camera, and the back of the eye, called the retina, is the film. Objects that your eyes see are projected onto the retina, and these pictures are sent to the brain by way of nerve signals. The brain detects these signals, puts them together to form an image, and that's how you see. It's amazing that it all happens so quickly — in a split second!

When a kid has strabismus, the eyes don't focus together on the same object and each eye sends a different picture to the brain. As a result, the brain might see two images (double vision) or the object looks blurry.

Kids' brains are really smart, and they don't like getting two different pictures instead of one. To fix the problem, the brain may ignore the picture coming from the one eye so it gets only one clear image. By shutting off the bad eye in favor of the good one, the bad eye gets weak or lazy (causing amblyopia), and without treatment the bad eye might eventually even become blind.

What Will the Doctor Do?

Usually doctors diagnose strabismus when a baby or young kid has a regular checkup. If a doctor or parent suspects a kid has strabismus, he or she will be sent to a special eye doctor called an ophthalmologist (say: af-thuh-mah-luh-jist). The doctor will examine the kid's eyes and ask him or her to read a chart on the wall or look into a microscope-type machine. None of these tests hurt.

If the doctor thinks a kid has strabismus, there are different ways to treat it. Some kids just need to wear glasses. Others may need surgery to straighten their eyes. Kids who have amblyopia will need to wear a patch over the good eye to strengthen the weaker one. For any kid who has strabismus or amblyopia, starting treatment as soon as possible is the best way to improve vision.

What's It Like?

Sometimes kids who have strabismus get teased. Like teasing for any reason, this causes hurt feelings. If you know someone with strabismus, be a friend and do not tease him or her.

And if you are the one who has strabismus, talk with a parent, teacher, or counselor if you are being teased. The good news is that this condition almost always can be treated, so someday you can say so long to strabismus!

Reviewed by: Jonathan H. Salvin, MD
Date reviewed: August 2010