The fundamental spectral sensitivity functions of the human visual system define a color space which ca.n be employed to design better color user interfaces. In particular, this color space makes it possible to accomodate individuals with color deficient vision. In order to screen potential users of computer graphics systems, traditional color vision tests, such as the Farnsworth-Munsell 100 hues test, can be implemented using a digitally controlled color television monitor, and these tests can be extended in ways that improve the specificity of their diagnoses. To assist in the design of computer graphic displays, a picture of the world as seen by color deficient observers can be synthesized and guidelines can be given for the selection of colors to be presented to color deficient observers.