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A pentaprism. A perspective drawing showing a roof pentaprism commonly used in a single lens reflex camera (SLR). The image is flipped laterally by the prism. A pentaprism is a five-sided reflecting prism used to deviate a beam of light by a constant 90°, even if the entry beam is not at 90° to the prism.
A Perger prism or Perger–Porro prism system is a prism, that is used to invert (rotate by 180°) an image. The special feature of this prism is that, like a traditional double Porro prism system, it manages this with only four beam deflections and has neither a roof edge with the accompanying phase correction problems, a mirrored surface or ...
Ophthalmology (/ˌɒfθælˈmɒlədʒi/ OFF-thal-MOL-ə-jee) is a surgical subspecialty within medicine that handles the diagnosis and treatment of eye disorders.[1] [2] Ophthalmologists are physicians (M.D./D.O/have a doctorate in medicine) that undergo subspecialty training in medical and surgical eye care. [3]
Prism adaptation is a sensory-motor adaptation that occurs after the visual field has been artificially shifted laterally or vertically. It was first introduced by Hermann von Helmholtz in late 19th-century Germany as supportive evidence for his perceptual learning theory (Helmholtz, 1909/1962). [1]
The cause of congenital fourth nerve palsy is unclear in most cases. It may be neurogenic in origin, due to a dysgenesis of the CN IV nucleus or nerve, but a clinically similar palsy may result from absence or mechanical dysfunction (e.g., abnormal laxity) of the superior oblique tendon.
Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye. [5] [6] The affected area flickers but is not dark. It then gradually expands outward ...
The Stanford prison experiment (SPE) was a psychological experiment performed during August 1971.It was a two-week simulation of a prison environment that examined the effects of situational variables on participants' reactions and behaviors.
If the beam from the eye travels infinitely fast this is not a problem. [ 32 ] In 55 BC, Lucretius , a Roman who carried on the ideas of earlier Greek atomists , wrote that "The light & heat of the sun; these are composed of minute atoms which, when they are shoved off, lose no time in shooting right across the interspace of air in the ...