Image from page 631 of "The American encyclopedia and dictionary of ophthalmology Edited by Casey A. Wood, assisted by a large staff of collaborators" (1913)
Publisher: Chicago : Cleveland Press
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Binocular Loupe. —there being no distortion. Absolute and comfortable binocular \ision.Great working distance between lenses and object viewed. No ob-struction to the view of surrounding objects. May be used in con-nection with a reflecting mirror or other illuminating apparatus. Maybe worn over spectacles or eyeglasses; or correcting lenses may beinserted in the open cells of the instrument.The sphero-prisms are adjustable horizontally for the purpose of 4612 EXAMINATION OF THE EYE obtaining coiiifoitaKIc liiiiociilar vision—regardless of accommodationor convergence. The Zeiss binocnlar telescopic magnifier is also sliown and is a thor-oughly satisfactor.x- in.stiuniciit. It is a combination of simple magni-fiers with a pi-isni feleseoi)e. Sneh a coinl)ination furnishes magnifyingpowers ranging from 2 to 80 diameters, whilst the instrument can beheld a very considerable distance away from the object. This is aquality which greatly eidiances its utility in the hands of medical men
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CARL ZEISSJElhA Zeiss Electrically Lighted Binocular Telescopic Magnifier Attached to Head Band. and, in fact, all observers to whom a long working distance is an im-portant consideration. For the finer and more thorough examination of the cornea somemeans of higher nuignifieation must be employed. The most perfectmethod is the use of a regular corneal microscope. Czapski s binocularinstrument is one of the latest and most complete. See Vol. V, p. 3390,of tliis Encj/clopedia. The binocular vision in it is obtained not bya division of light passing through a single objective, but by a com-bination of two microscopes, each complete in itself. Each of thecomponent microscopes consists of objective and eye-piece in coml)ina-tion with a Porro prism. EXAMINATION OF THE EYE 4613 The use of the Porro prism permits of a mueli shorter tube lengthand secures a larger field than would be possible otherwise, except bya much more bulky and inconvenient design. Pupillary distances between 56-76 mm.
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