Color Matching in Diabetes: Optical Density of the Crystalline Lens and Macular Pigments

PURPOSE. To measure the optical density of the crystalline lens and macular pigments in a group of patients with diabetes mellitus and compare the results with those in a group of control subjects. METHODS. Color matches were performed using a Wright tri-stimulus colorimeter. The reference wavelength used was 490 nm, desaturated with 650 nm. Lens optical density was mea-sured by mixing spectral primaries of wavelengths 420, 515, and 650 nm to match the reference. Wavelengths 420 and 515 nm were chosen, because they are absorbed equally by the macular pigment. To measure macular pigment density, two color matches were performed, one foveal and one 5 ° extrafo-veal. The reference stimulus was matched by mixing spectral primaries of 460, 530, and 650 nm. The ratio of the foveal to extrafoveal color match gives the optical density of the macula