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Distribution of rods and cones along a line passing through the fovea and the blind spot of a human eye [1]. A blind spot, scotoma, is an obscuration of the visual field.A particular blind spot known as the physiological blind spot, "blind point", or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the ...
Normal vision vis-à-vis disturbed vision. In addition to visual snow, many of those affected have other types of visual disturbances such as starbursts, increased afterimages, floaters, trails, and many others. [15] Visual snow likely represents a clinical continuum, with different degrees of severity.
Retreating calving front of the Jacobshavn Isbrae glacier in Greenland from 1851 - 2006. Nature photojournalist James Balog founded the Extreme Ice Survey in 2007 after spending much of the previous two years photographing receding glaciers for National Geographic [4] and The New Yorker. Balog saw extraordinary amounts of ice vanishing with ...
Blind spot (vision), also known as the physiological blind spot, the specific scotoma in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc Optic disc , also known as the anatomical blind spot, the specific region of the retina where the optic nerve and blood vessels pass through to connect to ...
The visual system is the physiological basis of visual perception (the ability to detect and process light).The system detects, transduces and interprets information concerning light within the visible range to construct an image and build a mental model of the surrounding environment.
A scotoma may include and enlarge the normal blind spot. Even a small scotoma that happens to affect central or macular vision will produce a severe visual disability, whereas a large scotoma in the more peripheral part of a visual field may go unnoticed by the bearer because of the normal reduced optical resolution in the peripheral visual field.
Much of the human cerebral cortex is involved in vision. There were two major ancient Greek schools, providing a primitive explanation of how vision works. The first was the "emission theory" of vision which maintained that vision occurs when rays emanate from the eyes and are intercepted by visual objects. If an object was seen directly it was ...
The first two sort of floaters may collect over the fovea (the center of vision), and therefore be more visible, when a person is lying on his or her back looking upwards. Blue field entoptic phenomenon has the appearance of tiny bright dots moving rapidly along squiggly lines in the visual field.