The Ishihara Test


While discussing ‘Colour Blindness’ before SC [Pranay Poddar v. State of Tripura, Civil Appeal No. 4393 of 2017], Senior Advocate K.V. Vishwanathan quoted Shinobu Ishihara, a Professor at Tokyo Imperial University, who, in 1916, had developed a diagnostic method which is still the most common test for ‘Colour Vision Deficiency’; and is called Ishihara.

The test consists of a number of coloured plates, called Ishihara as well, 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 existence of a deficiency is usually clear after a few plates.

Ishihara Plate No. 1
Ishihara Plate No. 1

Though many methods for color vision testing are available there is no consensus on the ideal method, with different countries using different tests. In India, Ishihara charts are most widely used, with additional use of Edridge-Green Lantern in Civil Services.


Eldridge-Green Lantern, 1891 was used by U.S. Navy for qualification of midshipmen and line officers prior to adoption of test of Farnsworth Lantern (FALANT) in 1953. FALANT is the final qualifying test for U.S. Navy, U.S. Coast Guard Academy and U.S. Merchant Marine Academy.

One might remember Professor Hubert J. Farnsworth from Futurama, an American animated science fiction sitcom [IMDb 8.5/10].

Professor Farnsworth

In ‘All the Presidents’ Heads’ [23rd Episode, 6th Season] he reveals, he has descended from Dean Farnsworth, creator of FALANT.