Parts of the eyes
Eyes are made up of several layers. The outer layer is made up of a curved and clear layer called the CORNEA. The white part of your eye is called the SCLERA. The sclera is a tough membrane that covers most of the eye and helps it have the shape it does.
The colored part of your eye is called the IRIS. The iris is the next layer of your eye. In the center of your iris you can see a small black circle, which is called the PUPIL. The pupil lets light into your eye.
Behind the iris is the LENS and the area behind the lens is called the VITREOUS BODY, which is filled with a gel-like substance called the VITREOUS HUMOR. The RETINA is in the very back of the eyeball
Light passes through your cornea and enters the pupil. The muscles of your eyes will cause your pupils to shrink or get bigger, which helps the pupil control how much light goes into your eye. So, when you are in a dark place your pupils get really big and when you are in bright light, your pupils get really small.
The light goes to the lens of your eye. Your lens can change shapes to help you see clearly. When you are looking at something close up, the lens gets thick and when you are trying to focus on something far away the lens gets thin. When the lens does this it helps the retina focus on what you are seeing. Whatever you are looking at appears upside-down in the retina. The retina then processes what you are looking at and turns the image into nerve impulses, which are sent to your brain through the optic nerve. When the message is received in your brain everything turns upright again
Common Eye Problems
Do you or any of your friends wear glasses or contact lenses? Ever wonder why? Here is a list of eye conditions that might cause people to wear glasses or contact lenses.
Nearsightedness
You have probably heard people say they are nearsighted but what does that mean? It means, basically, that you can see things that are near-clearly. Things that are far away might appear fuzzy or blurry. This is because the lens or the cornea is not refracting light properly. Sometimes one or both of the eyes is too long. Images get focused right in front of the retina instead of on the surface of the retina.
Farsightedness
This is when you can see things far away-clearly, but objects that are close to you are fuzzy or blurry. Unlike someone who is nearsighted, when you are farsighted your eyeballs are too short. When the eyeball is too short images are focused behind the retina's surface instead of right on it.
Astigmatism
This means the cornea is an uneven shape and it bends light in different directions. When this happens what you see is distorted and appears fuzzy or blurry.
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Eye Safety Tips
Always use proper lighting when reading, writing, watching television, or using your computer.
Don't point with sharp objects; you never know who you might accidentally bump into.
Don't run or walk quickly with sharp objects in your hands.
Don't throw pointy or sharp objects in the direction of others.
Wash your eyes out with water if you feel like something (like a bug) gets in there. You can also get an adult to look into your eye so that they can get the foreign object out.
If you are having trouble seeing the chalkboard or overhead at school let your parents know. It might be time for you to visit the eye doctor.
Give your eyes a rest when reading, watching TV, or working on the computer.
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