Vision Impairment and Blindness or Low vision

Vision Impairment and Blindness or Low vision 

Vision impairment, or low vision, means that even with eyeglasses, contact lenses, medicine or surgery, you don't see well. Vision impairment can range from mild to severe. The leading causes of vision impairment and blindness in the United States are age-related eye diseases: macular degeneration, cataract and glaucoma. Other eye disorders, eye injuries and birth defects can also cause vision loss.
A loss of vision means that you may have to reorganize your life and learn new ways of doing things. If you have some vision, visual aids such as special glasses and large print books can make life easier. There are also devices to help those with no vision, like text-reading software and braille books.
Sometimes, vision loss is preventable. Regular comprehensive eye exams and prompt treatment are critical.

NIH: National Eye Institute

source:http://www.nlm.nih.gov/medlineplus/visionimpairmentandblindness.html