To the Editor.
—In the course of the third program of the US National Health Survey,1 the opportunity was taken to estimate incidence of color vision deficiency in a specially selected group, designed to be a fair sample of youths between the ages of 12 and 17 years. Taking into account age, sex, race, family income, geographic region, and population size of place of residence, a stratified probability sample in each of five successive stages was taken; details of the method are given in an appendix.1 The object of the study was to determine factors of physical and intellectual growth and development. Color vision testing was performed in the total sample by means of a selection of seven Ishihara plates, as suggested by Sloan and Habel.2 Those failing any of the Ishihara plate tests were then screened with the American Optical Company (AOC)3 and Hardy-Rand-Rittler (HRR)
Taylor WOG. Color Vision Deficiencies in American Youths. Arch Ophthalmol. 1976;94(6):1056. doi:10.1001/archopht.1976.03910030544028