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Showing papers on "Foveal published in 1969"


Journal ArticleDOI
TL;DR: Fovea centralis in the human retina was studied with light and electron microscopes on a glutaraldehyde-osmium tetroxide fixed and epoxy resin embedded specimen and a relatively large amount of Muller cell processes is recognized at the center of the fovea.
Abstract: Fovea centralis in the human retina was studied with light and electron microscopes on a glutaraldehyde-osmium tetroxide fixed and epoxy resin embedded specimen. A relatively large amount of Muller cell processes is recognized at the center of the fovea. These cells constitute the floor of the fundus and possess a watery cytoplasm among central cone fibers in an area about 50μ in diameter. The mitochondria of the foveal cone tend to be dispersed in the inner segment and outer cone fiber. At the center, no ellipsoid is discernible in the inner segment of the foveal cone. The basal lamina along the vitreal surface is extremely thin at the fundus of the fovea. The center of the fovea externa, about 80μ in diameter, shows a slight convex elevation.

275 citations


Journal ArticleDOI
TL;DR: The results are interpreted as reflecting the effect of an attention-demanding central task on the size of the functional visual field.
Abstract: The effect of a central task on peripheral vision was investigated by obtaining luminance thresholds for stimuli presented from 20° to 90° in the periphery. A control group observed a steady foveal...

103 citations


Journal ArticleDOI
TL;DR: The results obtained with four observers confirm the presence of tritanopia when small brief stimuli are viewed foveally but fail to confirm it in the periphery, giving support to the notion that fovealtritanopia is due to the depressed sensitivity of the blue receptor mechanism found in the central fovea.
Abstract: The names given to spectral stimuli from 480 to 610 mμ and to a white-light test stimulus were obtained using 11′ or 21′ diam stimulus fields, exposed for 20 msec in the fovea and for 20 and 200 msec at 5° and 10° in the periphery The experiment was designed to test the hypothesis that normal color vision is replaced by tritanopic vision in all parts of the retina if the total luminous energy is sufficiently reduced The results obtained with four observers confirm the presence of tritanopia when small brief stimuli are viewed foveally but fail to confirm it in the periphery Rather, reduced color vision in the periphery is more nearly characteristic of deuteranomaly which ends ultimately in colorless vision These results are discussed as giving support to the notion that foveal tritanopia is due to the depressed sensitivity of the blue receptor mechanism found in the central fovea

45 citations


Journal ArticleDOI
TL;DR: The threshold velocity at which a light, rotated in a fronto-parallel plane around a foveal fixation target, appears as a “filled” band of light rather than a moving luminous object was determined with parametric manipulation of eccentricity of the moving target; arc length traversed; and luminance and wavelength composition of the target.

16 citations


Journal ArticleDOI
Adam Atkin1
TL;DR: The results indicated that a small nonfoveal region of the retina may provide the dominant controlling input for saccade-associated pursuit initiation even in the presence of conflicting velocity information from the fovea or from other parts ofThe retina.

12 citations