TEST ISHIHARA 10 PLATE BOOK COLOR BLIND TEST UNLETTERED

Ishihara Test Chart Books, For Color Deficiency. 10 Plate Book (Unlettered Persons and Children). 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. Consist 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. Color plates are incased in specially designed album-type books for ease of handling. Detailed instructions included. 1 each.