Color vision in humans is best in a small central region of the retina of the eye. This region, called the fovea, contains a very high proportion of the photoreceptors called cone cells, which are specialized for different wavelengths of the visible spectrum. Cone cells are present but not so densely packed outside the fovea, and we have very little understanding of whether the foveal processes such as "color opponent" mechanisms work in these more peripheral areas where there is a far higher proportion of the rod photoreceptors that are not specialized for color. This study uses a novel approach integrating the latest anatomical data with quantitative psychophysical experiments to determine the role of wavelength and intensity in color vision for stimuli striking outside the fovea. Results will provide an excellent test whether our models for foveal color vision are generally valid or need modification, and will have an impact not only on visual neuroscience, but on artificial vision and the psychology of perception.
