hard lens

hard lens
a contact lens of rigid plastic or silicon, exerting light pressure on the cornea of the eye, used for correcting various vision problems including astigmatism. Cf. soft lens.

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Universalium. 2010.

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  • hard lens — hard′ lens′ n. oph a contact lens of rigid plastic or silicon, exerting light pressure on the cornea of the eye Compare soft lens …   From formal English to slang

  • hard lens — a contact lens of rigid plastic or silicon, exerting light pressure on the cornea of the eye, used for correcting various vision problems including astigmatism. Cf. soft lens. * * * hard lens, a contact lens made firm plastic that adheres to the… …   Useful english dictionary

  • Lens speed — refers to the maximum aperture diameter, or minimum f number, of a photographic lens. A lens with a larger maximum aperture (that is, a smaller minimum f number) is a fast lens because it delivers more light intensity (illuminance) to the focal… …   Wikipedia

  • Lens clock — A lens clock is a mechanical dial caliper that is used to measure dioptric power of a lens. It is a specialized version of a spherometer. A lens clock measures the curvature of a surface, but gives the result in diopters, assuming the lens is… …   Wikipedia

  • hard — {{Roman}}I.{{/Roman}} adj. 1 solid/stiff VERBS ▪ be, feel, look, seem ▪ The chairs felt hard and uncomfortable. ▪ become, go …   Collocations dictionary

  • lens — n 1. eyepiece, Optics. ocular, Optics. objective, Optics. object glass or lens; telescope, field glass, spy glass; magnifier, magnifying glass, glass, hand lens, loupe; monocle, eyeglass. 2. lenses binoculars, opera glasses, lorgnette; eyeglasses …   A Note on the Style of the synonym finder

  • contact lens — one of a pair of small plastic disks that are held in place over the cornea by surface tension and correct vision defects inconspicuously. Cf. hard lens, intraocular lens, soft lens. [1885 90] * * * Thin artificial lens worn on the surface of the …   Universalium

  • soft lens — a nonrigid contact lens made of porous plastic, having a high water content that is replenished from eye surface moisture. Also called hydrophilic. Cf. hard lens. * * * soft lens noun A flexible contact lens of a hydrophylic material which allows …   Useful english dictionary

  • soft lens — a nonrigid contact lens made of porous plastic, having a high water content that is replenished from eye surface moisture. Also called hydrophilic. Cf. hard lens. * * * …   Universalium

  • contact lens hydrophobic — hard contact l …   Medical dictionary

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