Contrast is enhanced by yellow lenses because of selective reduction of short-wavelength light.
PURPOSE: Although many studies have shown a subjective preference for yellow lenses, there has been little success in determining the clinical nature of this benefit. METHOD: Contrast sensitivity, color vision, accommodative-convergence, and visual acuity were measured in a group of 20 young subjects along with subjective rating of their perception through clear control lenses (380-nm cut-off), yellow lenses (450-nm cut-off), dark yellow lenses (511-nm cut-off), and orange lenses (527-nm cut-off). RESULTS: A systematic detriment to color vision was found to occur with increasing cut-off wavelength of the yellow lenses (p < 0.001) and this was significantly correlated to subjective ratings of color (r = -0.66) and brightness (r = -0.34). Perceived brightness significantly improved for the yellow (450-nm cut-off) lens only (p < 0.001). Although tinted lenses reduced contrast sensitivity to a white on black grating, there was a significant improvement in low to midrange spatial frequencies when measured using a white-on-blue grating. CONCLUSIONS: The detriment in color vision caused by yellow-colored lenses enhances contrast when viewing bright objects against a blue-based background, such as the sky. Contrast of overlying objects is enhanced is due to the selective reduction of short-wavelength light by the yellow lenses.