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 child'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 child 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 and glaucoma, can cause vision problems or blindness.