File:The American encyclopedia and dictionary of ophthalmology Edited by Casey A. Wood, assisted by a large staff of collaborators (1913) (14579044988).jpg

Identifier: encyclopediaopth06wood (find matches)
Title: The American encyclopedia and dictionary of ophthalmology Edited by Casey A. Wood, assisted by a large staff of collaborators
Year: 1913 (1910s)
Authors: Wood, Casey A. (Casey Albert), 1856-1942
Subjects: Ophthalmology
Publisher: Chicago : Cleveland Press
Contributing Library: University of California Libraries
Digitizing Sponsor: Internet Archive

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the prism ocular of the Czapski loupe. He reflects the lightinto the eye, not wdth silvered glass, but with a plate of glass, thesides of which are inclined at an angle of one-quarter degree tosuperimpose the doubled reflections from the two surfaces of the plate. The De Zeng electric amplifying ophthalmoscope consists of anophthalmoscopic mirror, a telescope, a miniature electric lamp andcondenser, so connected and mounted as to form a small, hand, self-luminous amplifying ophthalmoscope. The position of the mirror wdth respect to the light source directsthe illuminating rays into the eye under observation in a line parallelwith the optical axis of the telescope. The light emanating from theobserved eye, in passing through the telescope to the ol^servers eye,causes the objects in view to be magnified in accordance with theamplifying power of the telescope, times the usual magnification asseen witli the nrdin;iry ophtlialnioscope while employing the direct EXAMINATION OF THE EYE 4759
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Gullstrands Largo Oiihthalmosoope. 4760 EXAMINATION OF THE EYE method of cxjiiiiiiiation. If tlir fundus of Ihc normal ■(• is viewedundci a iiui<i:nilication of 14 diamrtrrs when tlie direct method is em-))loye(l witli the ordinary ophthalmoseoi)e, the same fundus would beseen under an amplification of 42 diameters if observed tlirou^rh a 3-diameter amplifyint? telescope. The telescot)e has an amplifying jjower of 3 diameters, and is pro-vided with a graduated focusing adjustment for estimating theametroj)ia. The telescope, therefore, obviates the necessity of neutra-lizing lenses in the ordinary ophthalmoscope, since, by the relativeadjustment of tlie objective and eye-piece, all of the spherical equiva-lents in both plus and minus can ))e quickly and accurately obtained.There are three styles of mirrors employed. The circular mirror withcentral ajXrture is best adapted to all working distances beyond twoinches, the half mirror to very close range, and the small mir

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