The story
Designed by Dr. Shinobu Ishihara at the University of Tokyo, who first published his tests in 1917.
Etymology from Wiktionary, CC BY-SA 4.0.
Ishihara plate
Today it means: Any of a set of colored plates each containing a pattern of dots of various colors and sizes, forming a number or shape clearly visible to those with normal color vision; used in testing for color blindness. Full definition →