Tests for Color Deficiency Based the Pseudoisochromatic Principle

Tests composed of pseudoisochromatic plates provide one of the simplest methods of distinguishing between normal and deficient red-green color perception. During World War II the only such test generally available in the United States was the series of 46 plates printed by Beck & Co. and distributed by the American Optical Company. In several investigations reviewed by Farnsworth and Kimble, 1 it was shown that this series included many poor plates, some of which were failed almost as frequently by normal as by color-deficient subjects. To obtain a shorter and a more efficient dichotomous test, various selections of the more highly diagnostic plates were proposed. One of the earliest, a selection of 17 plates, known as the Abridged AOC Test, 2 has been used since about 1944 by the Army Air Forces. A selection of 18 plates was proposed by Hardy, Rand, and Rittler, 3 in 1947, spon- sored by