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Proceedings Paper

Contact lens design with slope-constrained Q-type aspheres for myopia correction
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Paper Abstract

The design of the rigid contact lens (CL) with slope-constrained Q-type aspheres for myopia correction is presented in this paper. The spherical CL is the most common type for myopia correction, however the spherical aberration (SA) caused from the pupil dilation in dark leads to the degradation of visual acuity which cannot be corrected by spherical surface. The spherical and aspheric CLs are designed respectively based on Liou’s schematic eye model, and the criterion is the modulation transfer function (MTF) at the frequency of 100 line pair per mm, which corresponds to the normal vision of one arc-minute. After optimization, the MTF of the aspheric design is superior to that of the spherical design, because the aspheric surface corrects the SA for improving the visual acuity in dark. For avoiding the scratch caused from the contact profilometer, the aspheric surface is designed to match the measurability of the interferometer. The Q-type aspheric surface is employed to constrain the root-mean-square (rms) slope of the departure from a best-fit sphere directly, because the fringe density is limited by the interferometer. The maximum sag departure from a best-fit sphere is also controlled according to the measurability of the aspheric stitching interferometer (ASI). The inflection point is removed during optimization for measurability and appearance. In this study, the aspheric CL is successfully designed with Q-type aspheres for the measurability of the interferometer. It not only corrects the myopia but also eliminates the SA for improving the visual acuity in dark based on the schematic eye model.

Paper Details

Date Published: 23 August 2017
PDF: 10 pages
Proc. SPIE 10375, Current Developments in Lens Design and Optical Engineering XVIII, 103750T (23 August 2017); doi: 10.1117/12.2273520
Show Author Affiliations
Wei-Jei Peng, Instrument Technology Research Ctr. (Taiwan)
Yuan-Chieh Cheng, Instrument Technology Research Ctr. (Taiwan)
Wei-Yao Hsu, Instrument Technology Research Ctr. (Taiwan)
Zong-Ru Yu, Instrument Technology Research Ctr. (Taiwan)
Cheng-Fang Ho, Instrument Technology Research Ctr. (Taiwan)
Khaled Abou-El-Hossein, Nelson Mandela Metropolitan Univ. (South Africa)


Published in SPIE Proceedings Vol. 10375:
Current Developments in Lens Design and Optical Engineering XVIII
R. Barry Johnson; Virendra N. Mahajan; Simon Thibault, Editor(s)

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