ABSTRACT
In work for the blind, this term "blind" refers to both sightless people and sighted people whose vision is seriously impaired. The problem of constructing a definition of blindness revolves around the question of where to draw a line among those with impaired vision. The number of blind people in the United States population is unknown. There is no regularly updated and complete nation-wide census of the blind, nor are complete administrative or other records kept on any substantial portion of the blindness population. These gaps complicate the task of describing the blindness population. According to the Binocular Visual Acuity study, for the period 1960–1962 there were an estimated 889,000 blind people between the ages of 18 and 79 in the non institutional population of the United States. Longevity is greater for women than for men, it is possible that the relationship between sex and blindness is in reality an index of the relationship of blindness to age.
