The human cone photoreceptor spectral sensitivities can differ between individuals. Large changes give rise to colour vision deficiencies, but even among colour-normals there is systematic individual variation. To limit the propagation of any systematic sampling bias in constructing the average spectral sensitivity functions used in research and industrial applications, it is useful to quantify the factors underlying this variation. The amino acid found at position 180 of OPN1LW, the gene responsible for encoding the L cone photopigment, is one source of individual variation in the L-cone spectral sensitivity. In this paper, group differences in the frequency of the L(S180) and L(A180) alleles are analysed from a combination of published reports and the genome sequencing database, gnomAD. We report evidence for significant group differences across ethnicity. Historical sampling bias in the data underlying the average L cone spectral sensitivity function therefore introduces ethnic bias in the applicability of these functions. We discuss the functional consequences of this variation by modelling failures of metamerism when this variability is not accounted for, the challenges of incorporating ethnicity variation in the existing L cone fundamental as adopted by the CIE Commission Internationale de l’Eclairage in 2006, and promising work on personalized cone fundamentals.
Schneider et al. (Tue,) studied this question.