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Proceedings Paper

Decentration of a spectacle lens
Author(s): Janina Bartkowska
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Paper Abstract

The correct placing of the lenses plays an important role in the ophthalmological practice. Centering errors cause disadvantageous prismatic effects and worsen image quality. The optical axes of the spectacles should pass by rotation centers of the eyes. An often met error consists in a faulty center distance, in a wrong positioning of the lenses axis or their placing too high, too low, or in the inclining without lowering. The errors reach some millimeters and some degrees of arc. In technical optics acceptable errors are fractions or hundredths of millimeters and minutes or seconds of arc. Therefore only first powers of decentration are taken into account. In the spectacle optics one cannot omit the second powers of decentration vector. An astigmatism proportional to the square of decentration arises in the center of the field. The off axis aberrations are a quadratic function of the decentration with linear term. The aberrations are calculated by admitting a virtual diaphragm in the point of intersection of the lens axis with the eye's view axis. This method can be applied also to the lenses with aspheric surface and to astigmatic lenses, if the decentration vector lies in one of the principal sections of toroidal surface.

Paper Details

Date Published: 22 October 1998
PDF: 16 pages
Proc. SPIE 3579, Ophthalmic Measurements and Optometry, (22 October 1998); doi: 10.1117/12.328326
Show Author Affiliations
Janina Bartkowska, Institute of Applied Optics (Poland)

Published in SPIE Proceedings Vol. 3579:
Ophthalmic Measurements and Optometry
Maksymilian Pluta; Mariusz Szyjer, Editor(s)

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