1 Cone Monochromatism

Abstract

In the preceding paper (Spivey, 1965) some of the visual characteristics of a number of members of a family with congenital monochromatism were described. In the present paper the results of spectral tests on the color vision of one of these patients (the propositus) are reported. Spivey found convincing evidence for the existence of two different kinds of photoreceptors in the propositus' retina, one recovering rather quickly following a bright light bleach, the other more or less slowly. It is quite unlikely that the second of these is anything but normal retinal rods, but there are at least two reasonable interpretations of the early adapting photoreceptors: They are the same as the quickly adapting "high intensity" photoreceptors of typical total color blindness which have the spectral sensitivity of rods (Sloan, 1958; Alpern et al, 1960; Blackwell and Blackwell, 1961, among others). They are one of the three types