The visual perception of the cataract eyes is composed of three elements, color, brightness, and haze. The color element is related to the reduced transmittance of light at short wavelengths of crystalline lens, the brightness element to the reduced transmittance at entire region of wavelength, and the haze element to the opacity of the crystalline lens. Researchers pay attention to only the color and brightness elements when they discuss on the color perception by the cataract eyes. We will show in this article that the haze element is also related to the color perception. There exists always environment light in our living situation. Light comes to the eyes from every direction. When the light enters the cataract eye it is scattered by the opacity of the crystalline lens and overlaps on the retinal image of objects that the eye is looking at. The environment light is usually white in color, and it reduces the colorimetric purity of the objects. The color appearance of the objects desaturates. This purity change was confirmed colorimetrically by measuring colors of test patches with the cataract simulating goggles placed in front of the lens of a colorimeter. The desaturation was then Confirmed psychophysically by subjects wearing the Goggles, who matched two color patches with and without the goggles. The same experiment was done by a subject whose right eye was operated for the cataract and the left eye was before the operation. Desaturation of color was found, though the desaturation was not as strong as with the goggles. In another psychophysical experiment the subject did the heterochromatic brightness Matching experiment by using his right eye and left eye, respectively, before and after operation. The results were inter-preted that all the color patches presented were perceived as being less saturated by eyes having cataracts. The importance was pointed out that, when we do experiments on the color perception by elderly observers we should not neglect the effect of the environment light. (C) 2008 Wiley Periodicals, Inc.