Richmond Products, a US‐based manufacturer of ophthalmic equipment, published this test in 1991. It still works on the principles of the Hardy Rand Rittler original test, but has been revised.
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The Ishihara test is a colour perception test for red-green colour deficiencies, the first in a class of successful colour vision tests called pseudo-isochromatic plates (“PIP”).
The Farnsworth–Munsell (FM) 100 Hue Test is the most famous D-15 dichotomous test which was originally introduced in 1947 by Mr. Farnsworth. The D-15 test is a so called arrangement test.

