AO PseudoIsochromatic Plates

A colorblind test published by the American Optical Company starting in 1940. At the outset of WWII, it became difficult for the USA and the allies to procure the two most popular colorblind tests at the time, the Stilling Test out of Germany, and the Ishihara test out of Japan. Instead, the AOC plagiarized a selection of the Stilling and Ishihara Plates. They did not hold the same level of quality as the plates that it draws from (Hardy 1947), but were used until the American Dvorine plates were created in 1944, and until the Ishihara Plates became available again after WWII.