"Blind" is a relative term, legally defined in the United States as vision of 20/200 or less in the better eye. More than 80 percent of blind people can perceive light, the American Foundation of the Blind reports, and many can see shadows. Blindness can be caused by loss of central vision, loss of peripheral vision, or both.
Statistics
In the United States, around 0.5 percent of the population is legally blind, the American Foundation for the Blind reported in 2007, a percentage that rises with age. Around 0.1 percent of the population between ages 40 to 49 is classified as blind, with the number increasing to 7 percent of those over age 80, the National Eye Institute reports.
Causes
The most common causes of blindness in the United States include glaucoma, damage to the optic nerve from elevated pressure within the eye; macular degeneration, which means deterioration in the central point of vision in the retina, the macula; diabetes; elevated blood glucose levels; and accident, MedlinePlus reports. Less than 3 percent of blindness is the result of injury, the American Foundation for the Blind states.
Employment
The employment rate is around 48 percent for blind people between the ages of 21 and 64, Lighthouse International reports, compared with 88 percent of people without disability in the same age group. Blind people can, however, work in a number of jobs, given the proper tools and training.
Low-Vision Aids
Many low-vision aids help blind people perform tasks that would otherwise be impossible. While many people envision a cane and a seeing-eye dog when they think of low-vision aids, only around 10,000 blind people in the United States and Canada have guide dogs, Guide Dogs for the Blind reports. Many more use talking watches, specially made knobs for stoves that have raised print that can be felt, and video magnifiers that project enlarged letters on a computer or television screen.
Braille Use
According to an article published by Jean Parker on March 3, 2008 on the Voice of America site American Life, only around 10 percent of blind people now read Braille, a series of raised dots developed by Louis Braille to allow them to read. While new computer technology such as talking books has in some ways replaced Braille, Chris Danielson of the National Foundation of Blind People says Braille is a necessary skill and that 90 percent of employed blind people know and use Braille. Mainstreaming of blind children in regular classrooms rather than having them attend schools for the blind accounts for some of the drop in Braille use.
