 Graham-Field Ishihara Test Chart Books for Color Deficiency,24 Plate Book,Each,1255Price: USD275.00 Graham-Field Ishihara Test Chart Books for Color Deficiency are accepted by leading authorities as a simple and accurate method for discovering congenital color blindness and red-green blindness, each in two forms, complete and incomplete. Includes four special plates for tests to determine the kind and degree of defect in color vision. Makes use of the peculiarity that in red-green blindness, blue and yellow appear remarkably bright compared with red and green.Graham-Field Ishihara Test FeaturesConsist of a number of colored plates.On each plate is printed a circle made of many different sized dots of slightly different colors, spread in a random manner.Within the dot pattern, and differentiated only by color, is a number.What, or even if, a number is visible indicates if and what form of color blindness the viewer has.The full test consists of thirty-eight plates, but the existence of a deficiency may be clear after fewer plates.Other products from H e a l t h P r o d u c t s F o r Y o u |