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The inner boundaries of peripheral vision can be defined in any of several ways depending on the context. In everyday language the term "peripheral vision" is often used to refer to what in technical usage would be called "far peripheral vision." This is vision outside of the range of stereoscopic vision.
Peripheral vision of the human eye. Vision span or perceptual span is a controversial concept referring to the angular span (vertically and horizontally), within which the human eye has sharp enough vision to perform an action accurately (reading or face recognition).
For example, binocular vision, which is the basis for stereopsis and is important for depth perception, covers 114 degrees (horizontally) of the visual field in humans; [7] the remaining peripheral ~50 degrees on each side [6] have no binocular vision (because only one eye can see those parts of the visual field). Some birds have a scant 10 to ...
Tubular vision: Since macular fibers are the most resistant to glaucomatous damage, central vision remains unaffected until the end stages of glaucoma. It results in tubular vision, or tunnel vision , by the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.
In the expression 6/x vision, the numerator (6) is the distance in metres between the subject and the chart and the denominator (x) the distance at which a person with 6/6 acuity would discern the same optotype. Thus, 6/12 means that a person with 6/6 vision would discern the same optotype from 12 metres away (i.e. at twice the distance).
Rods impact the eyes' light sensitivity and are responsible for peripheral vision, according to the American Academy of Ophthalmology. Cats can see up to six times better than the average human in ...
At the low end of the range is the absolute threshold of vision for a steady light across a wide field of view, about 10 −6 cd/m 2 (0.000001 candela per square meter). [ 22 ] [ 23 ] The upper end of the range is given in terms of normal visual performance as 10 8 cd/m 2 (100,000,000 or one hundred million candelas per square meter).
An examiner presents a test light of variable size and intensity. The light may move towards the center from the perimeter (kinetic perimetry), or it may remain in one location (static perimetry). The Goldmann method is able to test the entire range of peripheral vision and has been used for years to follow vision changes in glaucoma patients. [3]