Contrast thresholds versus border enhancement: effect of scattered light.
Contrast thresholds with sine wave grids, spatial frequency thresholds and border enhancement spread were measured while the amount of scattering in the retinal image was varied. Narrow-angle scattering similar to that produced by the cornea and crystalline lens was generated by specially designed filters. The purpose was to assess the effectivity of these widely different responses as measures of small order scattering effects. As noted by other investigators, spatial frequency thresholds proved insensitive to small amounts of scattering. On the other hand, contrast thresholds for high frequency targets and border enhancement spread both showed significant changes with small amounts of scattering. Of these two criteria, border enhancement proved to be the more consistent scattering index.
D006801:Humans; D008027:Light; D012542:Scattering, Radiation; D012684:Sensory Thresholds; D013028:Space Perception; D014794:Visual Fields