Have you ever put on a blindfold and pretended that you couldn't see? You probably
bumped into things and got confused about which way you were going. But if you had
to, you could get adjusted and learn to live without your sight.
Lots of people have done just that. They have found ways to learn, play, and work,
even though they have trouble seeing or can't see at all.
How Seeing Happens
Your eyes and your brain work together to see. The eye is made up of many different
parts, including the cornea, iris, lens, and retina. These parts all work together
to focus on light and images. Your eyes then use special nerves to send what you see
to your brain, so your brain can process and recognize what you're seeing. In eyes
that work correctly, this process happens almost instantly.
When this doesn't work the way it should, a person may be visually impaired, or
blind. The problem may affect one eye or both eyes.
When you think of being blind, you might imagine total darkness. But most people
who are blind can still see a little light or shadows. They just can't see things
clearly. People who have some sight, but still need a lot of help, are sometimes called
"legally blind."
What Causes Blindness?
Vision problems can develop before a baby is born. Sometimes, parts of the eyes
don't form the way they should. A kid's eyes might look fine, but the brain has trouble
processing the information they send. The optic nerve sends pictures to the brain,
so if the nerve doesn't form correctly, the baby's brain won't receive the messages
needed for sight.
Blindness can be genetic (or inherited), which means that this problem gets passed
down to a kid from parents through genes.
Blindness also can be caused by an accident, if something hurts the eye. That's
why it's so important to protect your eyes when you play certain sports, such as hockey.
Some illnesses, such as diabetes,
can damage a person's vision over time. Other eye diseases, such as cataracts
(say: KAH-tuh-rakts), can cause vision problems or blindness, but they usually affect
older people.