The visual characteristics of a case of Pigmentfarbenanomalie

Abstract

Observers with normal Rayleigh color matches who make errors on pigment tests have been classified as having Pigmentfarbenanomalie (PFA). We studied the visual characteristics of a case of PFA by measuring spectral sensitivities under various conditions. The spectral sensitivities on a white background showed three peaks although the peaks for the long-(L) and middle-wavelength (M) cone system were not as prominent as those of a normal observer. The patterns of sensitivity on a 430 nm background coincided with the sensitivity curve for L cones. The spectral sensitivity curve on a 700 nm background shows a broader shape in the middle and long wavelength region than that of either the L or M cones. The patterns of the field sensitivity action spectra for the middle and the long wavelength sensitive mechanisms coincided with the II₄ and the II₅ mechanisms of the normal observer respectively. The Fechner fraction of the M cone system showed significantly higher values than that of the L cone system. As a result, we are able to confirm the existence of both the L and M cones in PFA.