Next time you ride on a bus, take a look at the people around you. A lot of the riders -- both young and old -- will probably be wearing glasses. You may be one of them. Even the people without glasses may be giving their eyes assistance with contact lenses.
Your eyes work hard. When you are awake they constantly gather information and transmit it to your brain. Take a break from reading this page and look up at the room where you are sitting. How many objects do your eyes show you? They also show you how much light is in the room, what color everything is, and how close or far away things are.
The process of seeing takes place in a fraction of a second and happens automatically. You don't have to decide to see -- you just do it. But a lot of things happen in that split second it takes to look around.
Your eyes come equipped with several different parts to get the job done. Your eyes are shaped like ping-pong balls, and are about the same size. They're well-protected by your bony skull, and by your eyelids and eyelashes.
A tough coating covers each eyeball. Called the sclera, this is the part of your eye that looks white. A little hole in the sclera lets in light. You can see this hole, called the pupil, in the middle of the colored part of your eye.
The colored part of your eye, called the iris, contains special muscles to open and shut the pupil. You have probably noticed that your pupil is sometimes a tiny black dot, and sometimes a larger black hole. In very bright light, the pupil closes, the way you might pull down a blind on a window. In dimmer light, the pupil opens to let in more rays. You can see this happen if you go to a movie one afternoon with friends. Their pupils will be large in the dark theater and small outside in the bright light. So will yours.
A see-through disc called the cornea covers the outside of your pupil and iris. It collects light and sends it through the hole to the inside of your eyeball. That's where seeing starts.
Once light rays pass through your pupil, they are focused by your lens. This part of your eye looks a lot like the lens of a magnifying glass, but it's smaller. It's also very flexible. It can change shape to focus the light. It projects the light on a sensitive surface lining the back of your eyeball.
This surface is called the retina. An amazing thing happens on the retina. The light rays from outside form an upside-down image, or picture, on the back of the eye. Then special cells turn the picture into nerve signals, which rush off to your brain. The brain turns the picture right-side-up.
You have about 130 million light-sensitive cells on your retina. They come in two shapes, and have different jobs. Rods see black and white images, and can tell whether something is bright or dim. Cones see color. Together, these cells let you see.
All of this equipment sounds pretty complicated. And it is. Your eyes are very sensitivie and complex. Sometimes they don't work exactly right. That's where glasses or contact lenses come in.
To some people, close-up things look blurry. These people are called far-sighted. To others, faraway objects look blurry. These people are called near-sighted. The blurriness happens because the different parts of the eye don't work together quite right. The image formed on the retina isn't sharp and clear. Glasses change the way light enters the eye, allowing the equipment inside to focus clearly.
When you first get glasses, you may find that things look pretty weird. You feel as if you have entered a science fiction world. Objects have funny shapes. You reach for a glass of water on a table, and miss it by six inches. Don't worry. Before you got your glasses, your eyes were working overtime to keep things as clear as possible. Now that it's easier to focus, your brain is a little confused about how far away things are. It takes a few days to readjust.
But having glasses will make things easier for you now -- and as you get older. So polish up your glasses and take a good, sharp look at the world around you. Tips for Parents
Here are 10 symptoms that may indicate vision problems in school-age children:
1. Rubbing the eyes.
2. Closing or covering one eye.
3. Squinting at distant things like a chalkboard or TV screen.
4. Tilting the head to one side.
5. Holding reading material very close.
6. Avoiding books or close work.
7. Complaining of headaches after reading.
8. Moving the head instead of the eyes while reading.
9. Persistent carsickness.