Abstract
Objective: The human visual system alters its focus by a shape change of the eye lens. The extent to which the lens can adjust ocular refractive power is dependent to a significant extent on its material properties. Yet, this fundamental link between the optics and mechanics of the lens has been relatively under-investigated. This study aims to investigate this opto-mechanical link within the eye lens to gain insight into the processes of shape alteration and their respective decline with age. Methods: Finite Element models based on biological lenses were developed for five ages: 16, 35, 40, 57, and 62 years by correlating in vivo measurements of the longitudinal modulus using Brillouin scattering with in vitro X-ray interferometric measurements of refractive index and taking into account various directions of zonular force. Results: A model with radial cortical Young's moduli provides the same amount of refractive power with less change in thickness than a model with uniform cortical Young's modulus with a uniform stress distribution and no discontinuities along the cortico-nuclear boundary. The direction of zonular angles can significantly influence curvature change regardless of the modulus distribution. Conclusions: The present paper proposes a modelling approach for the human lens, coupling optical and mechanical properties, which shows the effect of parameter choice on model response. Significance: This advanced modelling approach, considering the important interplay between optical and mechanical properties, has potential for use in design of accommodating implant lenses and for investigating non-biological causes of pathological processes in the lens (e.g., cataract).
Original language | English |
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Article number | 8788637 |
Pages (from-to) | 999-1006 |
Number of pages | 8 |
Journal | IEEE Transactions on Biomedical Engineering |
Volume | 67 |
Issue number | 4 |
Early online date | 5 Aug 2019 |
DOIs | |
Publication status | Published - Apr 2020 |
Bibliographical note
This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/.Keywords
- Opto-mechanical modelling
- accommodation
- finite element analysis
- human eye lens
- radial cortical Young's moduli
- zonules
ASJC Scopus subject areas
- Biomedical Engineering