| lens, Bertrand | <microscopy> A small convergent lens placed between objectives and eyepiece. The lens focuses an image of the upper focal plane of the objective on the focal plane of the eyepiece. It is chiefly used with polarized light for inspecting the interference figure. It is also convenient for quickly verifying centreing, size, and uniform illumination of an aperture. (05 Aug 1998) |
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| lens capsule | The capsule enclosing the lens of the eye. Synonym: capsula lentis, crystalline capsule, lenticular capsule, phacocyst. (05 Mar 2000) |
| lens capsule, crystalline | The noncellular outer covering of the crystalline lens, secreted by the embryonic anterior and posterior epithelium. The embryonic posterior epithelium later disappears. (12 Dec 1998) |
| lens clock | A device for measuring the radii of the curvature of a spectacle lens. Synonym: lens clock. Origin: Geneva, Switzerland (05 Mar 2000) |
| 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 cortex, crystalline | The portion of the crystalline lens surrounding the nucleus and bound anteriorly by the epithelium and posteriorly by the capsule. It contains lens fibres and amorphous, intercellular substance. (12 Dec 1998) |
| lens, crystalline | The transparent biconvex body of the eye situated between the posterior chamber and the vitreous body, constituting part of the refracting mechanism of the eye. (12 Dec 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 nucleus, crystalline | The core of the crystalline lens, surrounded by the cortex. (12 Dec 1998) |
| 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) |