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Line-of-sight range; Line-of-sight (missile), the straight line between the missile and the target; Radar horizon; Line-of-sight propagation, electro-magnetic waves travelling in a straight line Non-line-of-sight propagation; Line-of-sight velocity, an object's speed straight towards or away from an observer
The Amsler grid showing the visual perception of the left eye of a person experiencing metamorphopsia (straight lines appear bent or curved) [1] [2]. Metamorphopsia (from Ancient Greek: μεταμορφοψία, metamorphopsia, 'seeing mutated shapes') is a type of distorted vision in which a grid of straight lines appears wavy or partially blank.
Classical image of the shape and size of the visual field [28]. The outer boundaries of peripheral vision correspond to the boundaries of the visual field as a whole. For a single eye, the extent of the visual field can be (roughly) defined in terms of four angles, each measured from the fixation point, i.e., the point at which one's gaze is directed.
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.
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 ...
Vision of humans and other organisms depends on several organs such as the lens of the eye, and any vision correcting devices, which use optics to focus the image. The eyes of many animals contains a lens that focuses the light of its surroundings onto the retina of the eye. This lens is essential to producing clear images within the eye.
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). [ 23 ] [ 24 ] 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).
Micropsia is a condition affecting human visual perception in which objects are perceived to be smaller than they actually are. Micropsia can be caused by optical factors (such as wearing glasses), by distortion of images in the eye (such as optically, via swelling of the cornea or from changes in the shape of the retina such as from retinal edema, macular degeneration, or central serous ...