The story
Devised by Shinobu Ishihara, a professor at the University of Tokyo, who first published his tests in 1917.
Etymology from Wiktionary, CC BY-SA 4.0.
Ishihara test
Today it means: A test for red-green color blindness, using a number of colored plates (Ishihara plates), each of which contains a circle of dots of various colors and sizes. Depending on the person's vision, certain dots within the pattern will appear to form recognizable numbers or shapes. Full definition →