Age-dependence of the average and equivalent refractive indices of the crystalline lens

Charman, W. Neil & Atchison, David A. (2014) Age-dependence of the average and equivalent refractive indices of the crystalline lens. Biomedical Optics Express, 5(1), pp. 31-39.

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Abstract

Lens average and equivalent refractive indices are required for purposes such as lens thickness estimation and optical modeling. We modeled the refractive index gradient as a power function of the normalized distance from lens center. Average index along the lens axis was estimated by integration. Equivalent index was estimated by raytracing through a model eye to establish ocular refraction, and then backward raytracing to determine the constant refractive index yielding the same refraction. Assuming center and edge indices remained constant with age, at 1.415 and 1.37 respectively, average axial refractive index increased (1.408 to 1.411) and equivalent index decreased (1.425 to 1.420) with age increase from 20 to 70 years. These values agree well with experimental estimates based on different techniques, although the latter show considerable scatter. The simple model of index gradient gives reasonable estimates of average and equivalent lens indices, although refinements in modeling and measurements are required.

Impact and interest:

3 citations in Scopus
3 citations in Web of Science®
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ID Code: 64997
Item Type: Journal Article
Refereed: Yes
Keywords: ophthalmic optics and devices, gradient indiex, lens, modelling, vision
DOI: 10.1364/BOE.5.000031
ISSN: 2156-7085
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Optometry & Vision Science
Copyright Owner: Copyright 2013 OSA
Deposited On: 03 Dec 2013 22:48
Last Modified: 17 Dec 2013 11:42

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