Grafco Ishihara Test Chart Book, for Color Deficiency, 14 Plate Book, 1/Ea, GHF1254

Product Description

Test Chart Books Features: 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. The full test consists of thirty-eight plates, but the existence of a deficiency may be clear after fewer plates. The Ishihara Color charts are accepted by leading authorities worldwide as a simple and accurate test method. Color plates encased in specially designed album-type books for ease of handling. Detailed instructions included. What is colorblindness? Color blindness (color vision deficiency) is a condition in which certain colors cannot be distinguished, and is most commonly due to an inherited condition. Red/Green color blindness is by far the most common (99%) form and causes problems in distinguishing reds and greens. Another color deficiency Blue/Yellow also exists, but is rare (1%) and there is no commonly available test for it. There is no treatment for color blindness, nor is it usually the cause of any significant disability. However, it can be very frustrating for individuals affected by it. Those who are not color blind seem to have the misconcepti

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