The<unk>  is a color perception test for red-green color deficiencies, the first in a class of successful color vision tests called pseudo-isochromatic plates ("PIP"). It was named after its designer, Shinobu<unk> , a professor at the University of Tokyo, who first published his tests in 1917. The test consists of a number of<unk>  plates, each of which depicts a solid circle of colored 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. Other plates are intentionally designed to reveal numbers only to those with a red-green color vision deficiency, and be invisible to those with normal red-green color vision. The full test consists of 38 plates, but the existence of a severe deficiency is usually apparent after only a few plates. There are also<unk> s consisting of 10, 14 or 24 test plates, and plates in some versions ask the viewer to trace a line rather than read a number.
Ishihara test
Spurling's test
Ober's test
Stenger test
Pandy's test
Weber test
Rinne test
Cozen's test