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  2. Refractive error - Wikipedia

    en.wikipedia.org/wiki/Refractive_error

    Rates among adults are between 15 and 49% while rates among children are between 1.2 and 42%. [7] Far-sightedness more commonly affects young children, whose eyes have yet to grow to their full length, and the elderly, who have lost the ability to compensate with their accommodation system .

  3. List of lens designs - Wikipedia

    en.wikipedia.org/wiki/List_of_lens_designs

    This list covers optical lens designs grouped by tasks or overall type. The field of optical lens designing has many variables including the function the lens or group of lenses have to perform, the limits of optical glass because of the index of refraction and dispersion properties, and design constraints including realistic lens element center and edge thicknesses, minimum and maximum air ...

  4. Optical glass - Wikipedia

    en.wikipedia.org/wiki/Optical_glass

    Optical glass refers to a quality of glass suitable for the manufacture of optical systems such as optical lenses, prisms or mirrors.Unlike window glass or crystal, whose formula is adapted to the desired aesthetic effect, optical glass contains additives designed to modify certain optical or mechanical properties of the glass: refractive index, dispersion, transmittance, thermal expansion and ...

  5. Crown glass (optics) - Wikipedia

    en.wikipedia.org/wiki/Crown_glass_(optics)

    Crown glass is a type of optical glass used in lenses and other optical components. It has relatively low refractive index (≈1.52) and low dispersion (with Abbe numbers between 50 and 85). Crown glass is produced from alkali-lime silicates containing approximately 10% potassium oxide and is one of the earliest low dispersion glasses.

  6. Retroreflector - Wikipedia

    en.wikipedia.org/wiki/Retroreflector

    The surface area of the reflector is proportional to the R I value, which increases as the reflective surface increases. [1] The R I value is also a function of the spatial geometry between the observer, light source, and reflector. Figures 1 and 2 show the observation angle and entrance angle between the automobile's headlights, bicycle, and ...

  7. Corrective lens - Wikipedia

    en.wikipedia.org/wiki/Corrective_lens

    Use contact lenses in place of or as well as eyeglasses. A contact lens rests directly on the surface of the cornea and moves in sync with all eye movements; consequently, a contact lens is always almost perfectly aligned on center with the pupil, and there is never any significant off-axis misalignment between the pupil and the optical center ...