Modified forms of Tscherning ellipses.
raytracing
spectacle lenses
third order theory
Journal
Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)
ISSN: 1475-1313
Titre abrégé: Ophthalmic Physiol Opt
Pays: England
ID NLM: 8208839
Informations de publication
Date de publication:
03 2021
03 2021
Historique:
received:
30
08
2020
accepted:
30
10
2020
pubmed:
21
2
2021
medline:
30
11
2021
entrez:
20
2
2021
Statut:
ppublish
Résumé
Third-order equations are well known for determining sagittal and tangential powers of a thin lens, corresponding to an eye rotating behind a lens to view objects away from the optical axis of the lens. These equations are referenced to the back surface of the lens and do not take into account the peripheral thickness of the lens. They do not give the same results as finite raytracing at small angles in which powers are referenced to the vertex sphere, which is the same distance from the centre-of-rotation for all object angles. Modified forms of the third-order sagittal and tangential image vergence error equations are developed to overcome the discrepancies. These are used to determine Tscherning ellipses for zero oblique astigmatism and zero mean oblique power error. While solutions to oblique astigmatism are not affected by the modifications, there are considerable changes to mean oblique error solutions.
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
401-408Informations de copyright
© 2021 The Author Ophthalmic & Physiological Optics © 2020 The College of Optometrists.
Références
Jalie M. Chapter 18. Spectacle lens design. In The Principles of Ophthalmic Lenses (5th ed). Association of Dispensing Opticians. London; 2016.
Atchison DA. Third-order theory and aspheric spectacle lens design. Ophthal Physiol Opt 1984; 4: 179-186.
Whitwell A. On the best form of spectacle lenses - XIX. Optician 1921; 61: 241-246.