PSY 368 Lecture Notes - Lecture 9: Vitamin A, Monochromacy, Test Light
9 Oct 2017
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Lecture 9 vision and the eye (cont) When looking at center ( a"), every other letter should be equally identifiable. Because acuity decreases w/ visual eccentricity, eccentric letters need to appear larger if they are to be identified as well as foveated letters (slide 33) Why is acuity best at fovea: near the optical axis; images at fovea therefore have fewest lens distortions, very few cell bodies located at fovea. Given that these cells would normally scatter light, their absence allows for clearer image: the type and distribution of photoreceptors at the fovea affect visual acuity. Fovea contains mainly cone" photoreceptors, which are specialized for detailed pattern vision. They are distrib diff on the retina: fovea contains only cones, peripheral retina contains rods and cones but mainly rods. Size of rod-free fovea is defined as the central 1-1. 7 degrees of visual angle. 2 separate visual syst central and peripheral.
