Full-spectrum cone sensitivity functions for X-chromosome-linked anomalous trichromats

Abstract

We derived the cone fundamentals for X-chromosome-linked anomalous trichromats for the wavelength range of 400–700 nm. Pigment templates were constructed from the cone fundamentals of normal trichromats after correction for ocular media absorption. The resultant retinal-level sensitivities had small irregularities in the short-wavelength region that were smoothed. The pigment templates, expressed as quantal sensitivities, were then shifted on a frequency abscissa to solve for the λ_max of the pigments of anomalous trichromats needed to predict average anomaloscope matching data. We found that the protanomalous M- and L′-cone pigments are separated by 10 nm and the deuteranomalous M′- and L-cone pigments are separated by 6 nm (rounded to the nearest nanometer), where M and L indicate middle- and long-wavelength sensitive, respectively. The triads of peak wavelengths for the corneal energy-based sensitivities were as follows: normal: 440, 543, and 566 nm; protanomalous: 440, 543, and 553 nm; and deuteranomalous: 440, 560, and 566 nm.