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Factors accounting for the great difference between peripheral and central vision are of three kinds. They are physical, such as the distortion of images from oblique rays, retinal, due to the distribution of rods and cones, and central, due to the interpretation of the images in consciousness. The present report describes the author's experiments to investigate these central factors. An apparatus was arranged in which an observer fixed a light through an aperture while objects were exposed at angles of 20, 40, 60 and 80° from the center of fixation by means of a projection apparatus. By means of a shutter, the time of exposure could be varied, but was usually one-tenth second. Six psychologists were used as observers for about 800 readings, the images exposed being drawn as accurately as the visual impression would allow. The figures used were geometric figures, combinations of circles and lines. As
Gifford SR. Psychological Factors in Peripheral Vision. Arch Ophthalmol. 1932;8(2):311. doi:10.1001/archopht.1932.00820150163022
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