著者

小穴 純

出版者

The Japan Society of Applied Physics

雑誌

応用物理 (ISSN:03698009)

巻号頁・発行日

vol.26, no.5, pp.206-210, 1957

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Positive ophthalmic lenses of the Punktal type, stigmatically corrected for an object plane at infinite distance, are often misused for a presbyopic eye to facilitate the viewing of near objects, with the result that these lenses show an astigmatic defect of considerable magnitude.<br> The ideal lens for presbyopia must be corrected, with respect to astigmatism, for an object plane at near distance, say 300mm from the lens. The designing method for these lenses is described and the designed results are tabulated. The results cover the range of ophthalmic power (expressed in diopter, D) from +0.25 D to +8.75 D in steps of 0.25 D each, and in each power three thicknesses and three refractive indices of material glass, i.e. nine variations are included. Thus the total number of the lenses designed amounts to 314.<br> The designing calculation is carried out in the final course of the present work by an electronic computer FUJIC of Fuji Photo Film Co.<br> The designing principle can be successfully applied on the designing of auxiliary lens attachments for photographic objectives used in close-up photography.