| lens clock | A device for measuring the radii of the curvature of a spectacle lens. Synonym: lens clock. Origin: Geneva, Switzerland (05 Mar 2000) |
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| lens, compound | <microscopy> A lens composed of two or more separate pieces of glass or other optical maternal. These component pieces or elements may or may not be cemented together. A common form of compound lens is a two-element objective, one element being a converging lens of crown glass and the other a diverging lens of flint glass. The combination of suitable glasses or other optical materials (plastics, minerals) properly ground and polished reduces aberrations normally present in a single lens. (05 Aug 1998) |
| lens, eye | <microscopy> The lens in an eyepiece nearest to the eye. (05 Aug 1998) |
| lens implantation, intraocular | Insertion of an artificial lens following removal of the crystalline lens, usually after cataract extraction. (12 Dec 1998) |
| lens-induced uveitis | Intraocular inflammation occurring after extracapsular cataract extraction;probably an immune reaction to the patient's liberated lenticular proteins. Synonym: lens-induced uveitis. (05 Mar 2000) |
| lens, magnetic | <microscopy> Circular electromagnets capable of projecting a precise circular magnetic field in a specified region. The field acts like an optical lens, having the same attributes (focal length angle of divergence etc.) and errors (spherical aberration, chromatic aberration, astigmatism etc.). They are used to focus and steer electrons in an Electron Microscope. (05 Aug 1998) |
| lens, negative | <microscopy> A lens that is thicker on the edges than in the centre, and which causes parallel light rays to diverge. Synonym: diverging lens. (05 Aug 1998) |
| lens neutral proteinase | <enzyme> Degrades alpha 2-crystallin; requires ca and mg; cleaves phe-ser bond in bradykinin; similar enzyme found in human lung Registry number: EC 3.4.24.5 Synonym: neutral proteinase 24.5 (26 Jun 1999) |
| lens pits | The paired depressions formed in the superficial ectoderm of the embryonic head as the lens placodes sink in toward the optic cup; the external openings of the pit's are closed as the lens vesicles are formed. (05 Mar 2000) |
| lens placodes | Paired ectodermal placode's that become invaginated to form the embryonic lens vesicles. Synonym: optic placodes. (05 Mar 2000) |
| lens, simple | <microscopy> A glass disk ground and polished with a spherical figure on one side and a plano, concave, or convex configuration on the other side. (05 Aug 1998) |
| lens stars | Congenital cataracts with opacities along the suture lines of the lens; may be anterior or posterior or both. (05 Mar 2000) |
| lens subluxation | Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ectopia lentis. (12 Dec 1998) |
| lens sutures | 9 to 12 faint lines on the anterior and posterior surfaces of the lens that radiate from the poles toward the equator; they mark the lines along which the ends of lens fibres abut. Synonym: lens stars, lens sutures. (05 Mar 2000) |
| lens vesicle | In the embryo, the ectodermal invagination that forms opposite the optic cup; it is the primordium of the lens of the eye. Synonym: lenticular vesicle. (05 Mar 2000) |