Age-related changes in refractive index distribution and power of the human lens as measured by magnetic resonance micro-imaging in vitro

Moffat, Brad A., Atchison, David A., & Pope, James M. (2002) Age-related changes in refractive index distribution and power of the human lens as measured by magnetic resonance micro-imaging in vitro. Vision Research, 42(13), pp. 1683-1693.

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We report a new technique for non-invasively mapping the refractive index distribution through the eye lens using magnetic resonance micro-imaging. The technique is applied to map the refractive index distribution throughout the sagittal plane of 18 human eye lenses ranging in age from 14 to 82 years in vitro. The results are compared with standard models for the human eye lens. They confirm that the refractive index distribution, when plotted as a function of normalised lens radius, is a function of lens age and differs both between the equatorial and axial directions and between the anterior and posterior halves of the optical axis. The refractive index of the lens nucleus exhibits a significant reduction with age amounting to 3:4 0:6 104 years1. The contribution of the gradient index (GRIN) to the lens power decreases by 0:286 0:067 D/year, accounting almost entirely for the estimated overall change in lens power with age for these lenses, which were probably in their most accommodated state. The results provide experimental verification of hypothesised changes in the GRIN that have previously been invoked as contributing to presbyopia and support the hypothesis that changes in the GRIN are sufficient to offset effects of increasing curvature of human lenses with age in their unaccommodated state.

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ID Code: 5476
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:
Keywords: Eye lens, Refractive index, Gradient index, Magnetic resonance imaging
DOI: 10.1016/S0042-6989(02)00078-0
ISSN: 0042-6989
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 2002 Elsevier
Deposited On: 20 Nov 2006 00:00
Last Modified: 15 Jan 2009 07:15

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