Tolerance and Nature of Residual Refraction in Symmetric Power Space as Principal Lens Powers and Meridians Change

Joint Authors

Abelman, Herven
Abelman, Shirley

Source

Computational and Mathematical Methods in Medicine

Issue

Vol. 2014, Issue 2014 (31 Dec. 2014), pp.1-8, 8 p.

Publisher

Hindawi Publishing Corporation

Publication Date

2014-11-11

Country of Publication

Egypt

No. of Pages

8

Main Subjects

Medicine

Abstract EN

Unacceptable principal powers in well-centred lenses may require a toric over-refraction which differs in nature from the one where correct powers have misplaced meridians.

This paper calculates residual (over) refractions and their natures.

The magnitude of the power of the over-refraction serves as a general, reliable, real scalar criterion for acceptance or tolerance of lenses whose surface relative curvatures change or whose meridians are rotated and cause powers to differ.

Principal powers and meridians of lenses are analogous to eigenvalues and eigenvectors of symmetric matrices, which facilitates the calculation of powers and their residuals.

Geometric paths in symmetric power space link intended refractive correction and these carefully chosen, undue refractive corrections.

Principal meridians alone vary along an arc of a circle centred at the origin and corresponding powers vary autonomously along select diameters of that circle in symmetric power space.

Depending on the path of the power change, residual lenses different from their prescription in principal powers and meridians are pure cross-cylindrical or spherocylindrical in nature.

The location of residual power in symmetric dioptric power space and its optical cross-representation characterize the lens that must be added to the compensation to attain the power in the prescription.

American Psychological Association (APA)

Abelman, Herven& Abelman, Shirley. 2014. Tolerance and Nature of Residual Refraction in Symmetric Power Space as Principal Lens Powers and Meridians Change. Computational and Mathematical Methods in Medicine،Vol. 2014, no. 2014, pp.1-8.
https://search.emarefa.net/detail/BIM-1016823

Modern Language Association (MLA)

Abelman, Herven& Abelman, Shirley. Tolerance and Nature of Residual Refraction in Symmetric Power Space as Principal Lens Powers and Meridians Change. Computational and Mathematical Methods in Medicine No. 2014 (2014), pp.1-8.
https://search.emarefa.net/detail/BIM-1016823

American Medical Association (AMA)

Abelman, Herven& Abelman, Shirley. Tolerance and Nature of Residual Refraction in Symmetric Power Space as Principal Lens Powers and Meridians Change. Computational and Mathematical Methods in Medicine. 2014. Vol. 2014, no. 2014, pp.1-8.
https://search.emarefa.net/detail/BIM-1016823

Data Type

Journal Articles

Language

English

Notes

Includes bibliographical references

Record ID

BIM-1016823