Ishihara test

This term refers to a specific clinical diagnostic tool. It is used primarily in medical and optometric settings to screen for red-green color vision deficiency. The test relies on pseudoisochromatic plates, where the target figure is hidden among dots of varying colors and sizes to prevent those with color blindness from using luminance or shape cues to guess the answer.

Because it is a proper noun derived from the name of its creator, Shinobu Ishihara, the word "Ishihara" is always capitalized. In professional medical reports, it is often referred to simply as "Ishihara plates" when discussing the physical materials used during the examination.