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Scintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache , but can also occur acephalgically (without headache), also known as visual migraine or migraine aura. [ 4 ]
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]
During an eye examination, the presence of suppression and the size and location of the suppression scotoma may be the Worth 4 dot test (a subjective test that is considered to be the most precise suppression test), or with other subjective tests such as the Bagolini striated lens test, or with objective tests such as the 4 prism base out test.
It expands the visual field by 20 degrees. He tested this concept on several patients in his private practice with great success using 40Δ Fresnel press-on prisms (Peli 2000). [ 1 ] Development of the lens and clinical trials were funded by NEI-NIH Grant EY014723 awarded to Chadwick Optical.
The visual field is "that portion of space in which objects are visible at the same moment during steady fixation of the gaze in one direction"; [1] in ophthalmology and neurology the emphasis is mostly on the structure inside the visual field and it is then considered “the field of functional capacity obtained and recorded by means of perimetry”.
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 ...
Prism spectacles with a single prism perform a relative displacement of the two eyes, thereby correcting eso-, exo, hyper- or hypotropia. In contrast, spectacles with prisms of equal power for both eyes, called yoked prisms (also: conjugate prisms, ambient lenses or performance glasses) shift the visual field of both eyes to the same extent. [5]
Cyclovergence can also be evoked by cyclodisparity of the visual field; the cyclodisparity can be introduced by dove prisms. [6] Here, use is made of the fact that a pair of dove prisms rotate an image optically if they are arranged one after the other and with an angular displacement relative to each other.