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  2. Multifocal intraocular lens - Wikipedia

    en.wikipedia.org/wiki/Multifocal_intraocular_lens

    Intraocular lenses that correct presbyopia are divided into two main categories: [1] Multifocal IOLs: achieve near and distance vision by having two (bifocal) or three (trifocal) focal points simultaneously. The function of multifocal IOL depends on the pupil size for refractive types. The concept is based on the principle that the pupil tends ...

  3. Periscope - Wikipedia

    en.wikipedia.org/wiki/Periscope

    a Objective lens b Field lens c Image erecting lens d Ocular lens e Lens of the observer's eye f Right-angled prism g Image-erecting prism. A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position.

  4. History of photographic lens design - Wikipedia

    en.wikipedia.org/wiki/History_of_photographic...

    They began breaking new ground around 1960: the Nippon Kogaku Auto-Nikkor 8.5–25 cm f/4-4.5 (1959), for the Nikon F, was the first telephoto zoom lens for 35mm still cameras (and second zoom after the Zoomar), the Canon 50mm f/0.95 (1961), for the Canon 7 35mm RF, with its superwide aperture, was the first Japanese lens a photographer might ...

  5. Aspheric lens - Wikipedia

    en.wikipedia.org/wiki/Aspheric_lens

    An aspheric lens or asphere (often labeled ASPH on eye pieces) is a lens whose surface profiles are not portions of a sphere or cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens . The asphere's more complex surface profile can reduce or eliminate spherical aberration and also reduce ...

  6. Eyeglass prescription - Wikipedia

    en.wikipedia.org/wiki/Eyeglass_prescription

    Eyeglass prescription. An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient. If an eye examination indicates that corrective lenses are appropriate, the ...

  7. Lens (geometry) - Wikipedia

    en.wikipedia.org/wiki/Lens_(geometry)

    A lens contained between two circular arcs of radius R, and centers at O1 and O2. In 2-dimensional geometry, a lens is a convex region bounded by two circular arcs joined to each other at their endpoints. In order for this shape to be convex, both arcs must bow outwards (convex-convex). This shape can be formed as the intersection of two ...

  8. Atmospheric diffraction - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_diffraction

    Atmospheric diffraction. Atmospheric diffraction is manifested in the following principal ways: Radio wave diffraction is the scattering of radio frequency or lower frequencies from the Earth's ionosphere, resulting in the ability to achieve greater distance radio broadcasting. Sound wave diffraction is the bending of sound waves, as the sound ...

  9. Optical coating - Wikipedia

    en.wikipedia.org/wiki/Optical_coating

    Optical coating. An optical coating is one or more thin layers of material deposited on an optical component such as a lens, prism or mirror, which alters the way in which the optic reflects and transmits light. These coatings have become a key technology in the field of optics. One type of optical coating is an anti-reflective coating, which ...