Dr Shinobu Ishihara from Japan introduced the most popularly known color blindness test in 1917. The test is a color perception test for red-green color deficiencies. It consists of a set of colored dotted plates (PseudoIsochromatic Plate or PIP), each of which shows certain numbers or patterns such as random lines.
Color blindness is a condition in which a person is unable to differentiate between colors. Color blindness is not a form of complete blindness instead it is a deficiency which doesn’t allow a person to see certain specific colors such as yellow and blue or red and green.