Design of Spectral Transmittance Factor for Sunglasses Using CIECAM02

An index for quantitative evaluation of the color discrimination property of sunglass lenses was calculated as the ratio of the color gamut area formed by the eight CIE-1974 test-color samples for the general color rendering index on the CIECAM02 colorfulness plane under the standard illuminant D65 after passing through the sunglass lenses under test to the gamut area formed by the samples on the plane under the illuminant D65. The index was validated by a very high simple correlation coef fi cient between the visual evaluation results and the indices of the color discrimination property. Furthermore, it was shown that blocking the spectral component around 565 nm effectively improves the color discrimination property and that a spectral transmittance factor that blocks wavelength components in a 500-nm area effectively improves color discrimination and enhances colorfulness for the color yellow simultaneously.