enow.com Web Search

  1. Ads

    related to: cheap contact lenses

Search results

  1. Results from the WOW.Com Content Network
  2. Ice lens - Wikipedia

    en.wikipedia.org/wiki/Ice_lens

    Ice lens. Pingo formed in arctic tundra as a result of periodically spaced ice lens formation. Ice lenses are bodies of ice formed when moisture, diffused within soil or rock, accumulates in a localized zone. The ice initially accumulates within small collocated pores or pre-existing crack, and, as long as the conditions remain favorable ...

  3. Low-dispersion glass - Wikipedia

    en.wikipedia.org/wiki/Low-dispersion_glass

    Low-dispersion glass ( LD glass) is a type of glass with a reduction in chromatic aberration (less rainbow effect). Crown glass is an example of a relatively inexpensive low-dispersion glass. Special low dispersion glass (SLD glass) and extraordinary low-dispersion glass (ELD glass) are glasses with yet lower dispersion (and yet higher price).

  4. Chromatic aberration - Wikipedia

    en.wikipedia.org/wiki/Chromatic_aberration

    For a doublet consisting of two thin lenses in contact, the Abbe number of the lens materials is used to calculate the correct focal length of the lenses to ensure correction of chromatic aberration. If the focal lengths of the two lenses for light at the yellow Fraunhofer D-line (589.2 nm) are f 1 and f 2 , then best correction occurs for the ...

  5. Acuvue - Wikipedia

    en.wikipedia.org/wiki/Acuvue

    Acuvue lenses got their start at Frontier Contact Lens Company, founded in Buffalo, New York in 1959 by Dr. Allen Isen, George Sitterle, and Dr. William Feinbloom. [1] Its early growth was attributed to its highly successful toric lens. In 1962, Seymour Marco joined the venture and Frontier moved its operations to Jacksonville, Florida. [2]

  6. Orthokeratology - Wikipedia

    en.wikipedia.org/wiki/Orthokeratology

    Orthokeratology, also referred to as Night lenses, Ortho-K, OK, Overnight Vision Correction, Corneal Refractive Therapy (CRT), Accelerated Orthokeretology, Cornea Corrective Contacts, Eccentricity Zero Molding, and Gentle Vision Shaping System (GVSS), is the use of gas-permeable contact lenses that temporarily reshape the cornea to reduce refractive errors such as myopia, hyperopia, and ...

  7. Focal length - Wikipedia

    en.wikipedia.org/wiki/Focal_length

    Focal length. The focal point F and focal length f of a positive (convex) lens, a negative (concave) lens, a concave mirror, and a convex mirror. The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a ...

  1. Ads

    related to: cheap contact lenses