ishihara test

noun Ophthalmology.

1. a test for determining color blindness by means of a series of cards each having colored dots that form one pattern to the normal eye and a different pattern to the eye that is color-blind.

n.

1. A test for color-vision deficiency employing a series of plates on which numbers or letters are printed in dots of primary colors surrounded by dots of other colors; the figures are discernible by individuals with normal color vision.