Colour vision is tested with help of the

(C) Ishihara plates # ISHIHARA COLOR TEST is an example of a color perception test for red-green color deficiencies.> It was named after its designer, Dr. Shinobu Ishihara, a professor at the University of Tokyo.> The test consists of a number of colored plates, called Ishihara plates, each of which contains a circle of dots appearing randomized in color and size.> Within the pattern are dots which form a number or shape clearly visible to those with normal color vision, and invisible, or difficult to see, to those with a red-green color vision defect.