- another term for protanopia, a form of color-blindness
- ‘The number of colour-blind artists in the history of art is probably larger than usually assumed, bur it is not possible to demonstrate daltonism simply by looking at an artist's pictures.’
- ‘It is one of the tests of reference to screen daltonism.’
- ‘The most common form of colorblindness is daltonism or a problem with red/green.’
Mid 19th century: from the name of John Dalton (see Dalton, John) + -ism.