| omnifocal lens | A lens for near and distant vision in which the reading portion is a continuously variable curve. (05 Mar 2000) |
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| orthoscopic lens | A spectacle lens corrected for distortion and curvature of the periphery. (05 Mar 2000) |
| electromagnetic lens | <apparatus> An electromagnet designed to produce a suitably shaped magnetic field for the focusing and deflection of electrons or other charged particles in electron optical instruments (cf. Electrostatic lens.) See: microscope, electron. (05 Aug 1998) |
| electron lens | <physics> A device for focusing an electron beam. (05 Aug 1998) |
| electrostatic lens | <physics> A lens employing a permanent magnet to produce a potential field capable of deflecting electron rays to form an image of an object. (cf. Electromagnetic lens). (05 Aug 1998) |
| toric lens | A lens in which both meridians are curved but not to the same degree. (05 Mar 2000) |
| trifocal lens | A lens with segments of three focal powers: distant, intermediate, and near. (05 Mar 2000) |
| epithelium of lens | The layer of cuboidal cells lying on the anterior surface of the crystalline lens inside the lens capsule. at the equator the cells elongate and give rise to the lens fibres. Synonym: epithelium lentis. (05 Mar 2000) |
| equator of lens | The periphery of the lens lying between the two layers of the ciliary zonule. Synonym: equator lentis. (05 Mar 2000) |
| exfoliation of lens | Sheetlike separation of the capsule of the lens; it may occur if the eyes are exposed to intense heat. (05 Mar 2000) |
| eye lens | <physics> The lens nearest the eye in any ocular. (05 Aug 1998) |
| fibres of lens | <biology, ophthalmology, physiology> The elongated cells of ectodermal origin forming the substance of the crystalline lens of the eye. Synonym: fibrae lentis. (05 Mar 2000) |
| field lens | <physics> The lower lens in an ocular, the lens nearest the object field. (05 Aug 1998) |
| lamina of lens | One of a series of concentric layers composed of the lens fibres that make up the substance of the lens. (05 Mar 2000) |
| Fresnel lens | <physics> A lens built up, progressively, in zones or steps, each zone with its own individual radius. Considerable spherical correction is attained, and the weight of the lens is greatly reduced. Fresnel lenses were originally designed for lighthouses but they are now attainable for small spotlights, automobile headlights, and similar uses. (05 Aug 1998) |