Search results
Results from the WOW.Com Content Network
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 (optics) An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are not prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base and rectangular sides.
White light is dispersed by a prism into the colors of the visible spectrum. The visible spectrum is the band of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light (or simply light). The optical spectrum is sometimes considered to be the same as the ...
Corrective lens. A pair of contact lenses, positioned with the concave side facing upward. A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia.
The effect of this will be that when a vertical beam of light in the distance travels towards the eye, the "minus" cylinder (which is placed with its axis lying horizontally – meaning in line with the patient's horizontal meridian relative to the excessively steep vertical meridian) will cause this vertical beam of light to slightly "diverge ...
Size of this PNG preview of this SVG file: 275 × 300 pixels. Other resolutions: 220 × 240 pixels | 440 × 480 pixels | 704 × 768 pixels | 939 × 1,024 pixels | 1,877 × 2,048 pixels . Original file (SVG file, nominally 275 × 300 pixels, file size: 36 KB)
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 most common application for this is the treatment of strabismus. By moving the image in front of the deviated eye, double vision can be avoided and comfortable binocular vision can be achieved. Other applications include yoked prism where the image is shifted an equal amount in each eye.
What links here; Upload file; Special pages; Printable version; Page information
Size of this PNG preview of this SVG file: 235 × 170 pixels. Other resolutions: 320 × 231 pixels | 640 × 463 pixels | 1,024 × 741 pixels | 1,280 × 926 pixels | 2,560 × 1,852 pixels . Original file (SVG file, nominally 235 × 170 pixels, file size: 6 KB)