Noun
Ishihara test (plural Ishihara tests)
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.
The software enables, for instance, a colorblind person to see the numbers in the Ishihara test. Source: Internet