The Ishihara Colour Test is an example of a colour perception test for red-green colour deficiencies. It was named after its designer, Dr. Shinobu Ishihara, a professor at the University of Tokyo, who first published his tests in 1917.
The test consists of a number of coloured plates, called Ishihara plates, each of which contains a circle of dots appearing randomized in colour and size. Within the pattern are dots which form a number or shape clearly visible to those with normal colour vision, and invisible, or difficult to see, to those with a red-green colour vision defect, or the other way around. The full test consists of 38 plates, but the existence of a deficiency is usually clear after a few plates. There is also the smaller test consisting only 24 plates.
Dhines Kumar has produced a short 8 minute video on YouTube on the Ishihara Colour Test with 24 plates. I have taped a few seconds of his presentation in the video below or if you want to watch the full video click here.