[Effect of transparent yellow and orange colored contact lenses on color discrimination in the yellow color range].

BACKGROUND: Colored transparent filters cause a change in color perception and have an impact on the perceptible amount of different colors and especially on the ability to discriminate between them. Yellow or orange tinted contact lenses worn to enhance contrast vision by reducing or blocking short wavelengths also have an effect on color perception.
METHODS: The impact of the yellow and orange tinted contact lenses Wöhlk SPORT CONTRAST on color discrimination was investigated with the Erlangen colour measurement system in a study with 14 and 16 subjects, respectively. In relation to a yellow reference color located at u' = 0.2487/v' = 0.5433, measurements of color discrimination thresholds were taken in up to 6 different color coordinate axes. Based on these thresholds, color discrimination ellipses were calculated. These results are given in the Derrington, Krauskopf and Lennie (DKL) color system.
RESULTS: Both contact lenses caused a shift of the reference color towards higher saturated colors. Color discrimination ability with the yellow and orange colored lenses was significantly enhanced along the blue-yellow axis in comparison to the reference measurements without a tinted filter. Along the red-green axis only the orange lens caused a significant reduction of color discrimination threshold distance to the reference color.
CONCLUSION: Yellow and orange tinted contact lenses enhance the ability of color discrimination. If the transmission spectra and the induced changes are taken into account, these results can also be applied to other filter media, such as blue filter intraocular lenses.