What is visual impairment?
Visual impairment happens when there is a problem with one or more parts of the eyes or the parts of the brain needed to process the images sent from the eyes. This prevents a person from seeing properly. People also often use the words “blind” or “blindness” when talking about visual impairment. Many people think blindness means a person can’t see at all, but this isn’t always true. Some people who are considered blind can still see a little light or shadows, but they can not see things clearly.
Causes of visual impairment
A person who is visually impaired may have been born with parts of his eyes that weren’t formed properly. The optic nerve that sends the picture to the brain may not be correctly formed, or the eyes may be damaged. Sometimes the eyes look totally normal, but the brain doesn’t correctly use the information the eye sends to it.
An unborn baby might develop a visual impairment if his mother contracts certain diseases while she is pregnant. Blindness may also be caused by an accident that damages the eye, or by certain diseases, including diabetes. Others lose their vision as they become older. We know also that visual impairment can be caused by heredity (say: huh-reh-dih-tee) or genes, meaning that a person is programmed at birth to develop visual impairment at some stage. Retinitis Pigmentosa (RP) is an example of visual impairment caused by heredity.
How do people who are blind or visually impaired move from one place to another?
People use white canes, guide dogs or the assistance of a person who is sighted to move around. They memorize certain routes that they travel regularly or use special tactile maps. Also, they use their senses of hearing, touch and smell to help them identify what is around them. Often these other senses become enhanced to compensate for their visual weakness.
How do people who are blind or visually impaired read?
Many people read Braille, which is a special code of raised dots that are punched on thick paper. They listen "talking books" - tapes or CDs of books and magazines, or use a special computer with particular software. Many people with low vision hold their book very close or use a magnifier to make the letters bigger.
