Effect of conicoid asphericity on the Tscherning ellipses of ophthalmic spectacle lenses

Smith, George & Atchison, David A. (1983) Effect of conicoid asphericity on the Tscherning ellipses of ophthalmic spectacle lenses. Journal of the Optical Society of America A: Optics and Image Science, 73(4), pp. 441-445.


One of the criteria in ophthalmic spectacle lens design is the elimination of oblique astigmatism. For a range of equivalent powers, Seidel (primary or third-order) astigmatism can be eliminated, and the solutions of back- (or front-) surface power are commonly displayed graphically in the form of ellipses (Tscherning ellipses). The Tscherning ellipses apply only to lenses constructed from spherical surfaces. If one or both surfaces are made aspheric, the solutions for zero astigmatism are no longer in the form of ellipses. If one surface, usually the front surface, is made as a conicoid aspheric, the solutions for zero astigmatism can be presented graphically similarly to the Tscherning ellipses. For any given equivalent power, there are two or no solutions for spherical lenses. However, there is always one and up to three solutions for conicoid aspheric lenses.

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ID Code: 4625
Item Type: Journal Article
Refereed: Yes
Additional Information: For more information, please refer to the journal's website (see link) or contact the author. Author contact details: d.atchison@qut.edu.au
Additional URLs:
Keywords: conicoid asphericity, Tscherning ellipses, spectacle lens, oblique astigmatism
ISSN: 0740-3232
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 1983 Optical Society of America
Deposited On: 17 Aug 2006 00:00
Last Modified: 15 Jan 2009 07:08

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