Light spread and scatter from some common adapting stimuli: computations based on the point-source light profile

A point source of light is not so imaged on the photoreceptor mosaic. The light is distributed over the retina by diffraction, imperfections in the optics of the eye, and scatter. The spatial distribution of light is specified quantitatively by the point-source light profile, which can be used in convolution to determine light spread from more complex visual stimuli. We use the Vos, Walraven and van Meeteren [Vision Res. 16, 215-219 (1976)] light profile to determine spread light in specific regions within the spared area of an illuminated surround, and within a thin spared ring in an otherwise uniformly illuminated circular field. Surrounds of different sizes and rings of various widths and diameters are evaluated.