Topic
Foveal
About: Foveal is a research topic. Over the lifetime, 2652 publications have been published within this topic receiving 94120 citations.
Papers published on a yearly basis
Papers
More filters
01 Jan 1973
TL;DR: Light-difference thresholds were measured in the center and periphery of the visual field at photopic and scotopic levels to show that peripheral targets at threshold appear brighter than foveal targets atreshold because a peripheral target at threshold has more luminance than a fovea target atreshold.
Abstract: Light-difference thresholds were measured in the center and periphery of the visual field at photopic and scotopic levels. Under photopic conditions the fovea has the lowest light-difference threshold. From the fovea to 10 degrees eccentricity threshold gradually increases. It remains constant up to approximately 35 degrees eccentricity in the temporal visual field (nasal retina). Beyond the edge of this plateau of constant light-difference threshold, it again increases to the limit of the visual field. Under scotopic conditions the extent of the plateau of constant light-difference threshold remains the same as under photopic conditions. The fovea itself, however, and its immediate environment are less sensitive than the plateau area. Subjective brightness of a supra-threshold target is not dependent on its position in the visual field. A target with a given luminance will elicit the same brightness sensation at all retinal positions. As a consequence of this brightness constancy throughout the visual field, peripheral targets at threshold appear brighter than foveal targets at threshold because a peripheral target at threshold has more luminance than a foveal target at threshold.
92 citations
TL;DR: The main result was that identification accuracy was very good, but eye-movement behavior was disrupted when a foveal scotoma was present, suggesting that foveAL information is not necessary but is beneficial for perceptual encoding during object identification.
Abstract: The purpose of the present study was to investigate the degree to which foveal information is necessary for object identification To explore this question, we used an artificial moving scotoma paradigm to eliminate a region of a currently viewed display in real time as a function of eye position Subjects examined linear arrays of four line drawings of objects while their eye movements were recorded Immediately following each array, a test probe was presented to test the degree to which the subject had identified those objects Three conditions were compared, one in which a central foveal scotoma was created, one in which an extrafoveal scotoma was created, and a control condition in which the scotoma was absent The main result was that identification accuracy was very good, but eye-movement behavior was disrupted when a foveal scotoma was present These results suggest that foveal information is not necessary but is beneficial for perceptual encoding during object identification; the loss of foveal information can be overcome as long as compensatory extrafoveal processing is possible
92 citations
TL;DR: The results strongly suggest that the convexiclivate fovea is a device for achieving improved fixation and improved sensitivity to movement of objects in the visual field at some sacrifice of acuity.
Abstract: The structure and distribution of the two principal types of fovea are briefly described. Using the convexiclivate central fovea of the eagle as a type the effect of refraction at the boundary of retina and vitreous humour on the foveal image is computed. It is shown that, when aberration and diffraction are taken into account, no improvement in acuity can result from refraction at the fovea. On the contrary, the results strongly suggest that the convexiclivate fovea is a device for achieving improved fixation and improved sensitivity to movement of objects in the visual field at some sacrifice of acuity. The application of these results to other variants of fovea is discussed, and a scheme indicating possible relations between function and geometrical form is proposed.
92 citations
TL;DR: The results indicate that at photopic background luminances, centre size increases from a foveal diameter of less than 9′ to 1° at 10° eccentricity, then more slowly to 1.75° at 70° eccentricities, and total perceptive field size increases more rapidly from 1° in the fovea to about 6.5° at70° eccentricITY.
92 citations
TL;DR: Overall, this data set provides rich expression profiles of the major human retinal cell types and highlights transcriptomic features that distinguish foveal and peripheral cells.
92 citations