The known unknowns of anomalous trichromacy

Anomalous trichromacy is the most common minority color vision phenotype, yet the category label obscures a large range of individual differences both in the underlying genetics and in color perception. This review explores both, particularly considering possible reasons for the smaller than expected observed relationship between the spectral sensitivities of anomalous cones and color discrimination. Also considered is the putative process of postreceptoral compensation, where anomalous trichromats may amplify the reduced color signals they receive from their cones to relatively normalize their color vision postreceptorally.