Quantitative analyses of color vision using the Farns-worth-Munsell 100-hue test confirm that the mode of inheritance is important for the prognosis of retinopathia pigmentosa. Cases involving the autosomal dominant mode of inheritance are characterized by slight functional losses whereas patients with the autosomal-recessive or the X-chromosomal-recessive mode of inheritance show pronounced defects in the photopic system. With time the degeneration affects the blue, the green and finally the red areas of the color spectrum.