Blindness is the condition of lacking visual perception - simply stated, a lack of vision. It can also refer to a loss of vision that cannot be corrected by contacts or glasses. People with vision worse than 20/200 are considered legally blind in most states. Partial blindness means that you have very limited vision while complete blindness means that you cannot see anything or any light. Blindness is due to physiological or neurological factors. The most common causes of blindness are cataracts and glaucoma. Sometimes blindness is caused by an injury to the eye, a genetic defect (albinism for example), or poisoning.
Many blind people can and do travel independently and they use a wide variety of tools and techniques in order to do so. Orientation and mobility specialists teach people with visual impairments how to travel safely and confidently by helping them to become familiar with the environment they live and often travel in. Blind people use tools such a white canes with red tips because these canes extend the person's range of touch sensation and can easily detect obstacles when swung in a circular motion on the ground around the user. Surprisingly, only a small number of blind people use guide dogs to help them get around. Guide dogs are trained to navigate around various obstacles and they also indicate when their owner should step down or up on the stairs. It is said that the helpfulness of guide dogs is limited by the inability of dogs to understand complex directions. More recently, blind people are using GPS technology as an aid for mobility. These programs assist the visually impaired person with orientation and navigation but haven't been proven to work better than canes or guide dogs. With the help of braille, blind people can read and use computers.
Blind people, like deaf people and others with so called "disabilities" can live normal, independent lives. White canes, guide dogs, braille, and orientation specialist assist the visually impaired with daily tasks such as reading and traveling.