TY - JOUR
T1 - Model of accommodation
T2 - Contributions of lens geometry and mechanical properties to the development of presbyopia
AU - Van De Sompel, Dominique
AU - Kunkel, Gary J.
AU - Hersh, Peter S.
AU - Smits, Alexander J.
N1 - Funding Information:
Supported in part by the Princeton Institute for the Science and Technology of Materials . Dominique Van de Sompel was supported by the Morgan W. McKinzie 1993 Senior Thesis Fund and a Davis United World Colleges Scholarship, Princeton University . Dr. Kunkel was partially funded by Princeton University as a Council on Science and Technology Postdoctoral Teaching Fellow .
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2010/11
Y1 - 2010/11
N2 - Purpose: To determine the relative importance of lens geometry and mechanical properties for the mechanics of accommodation and the role of these elements in the causes and potential correction of presbyopia. Setting: Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, USA. Design: Experimental study. Methods: Finite element methods and ray-tracing algorithms were used to model the deformation and optical power of the human crystalline lens during accommodation. The mechanical model treats the lens as an axisymmetric object, and the optical model incorporates a gradient refractive index. Using these models, the accommodation of a broad range of lenses with different geometries and mechanical properties were investigated. Results: The most significant result was that reshaping the 45-year-old lens to the geometry of the 29-year-old lens, while retaining the mechanical properties, restored the former's accommodation amplitude to 72% to 94% of that of the 29-year-old lens, depending on ciliary body displacement. That is, reshaping can add 1.8 to 3.7 diopters of accommodation. A sensitivity analysis showed that this result was robust over a wide range of mechanical and geometrical properties. Conclusion: The study results suggest that a significant amount of the loss of accommodation is due to changes in lens geometry. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.
AB - Purpose: To determine the relative importance of lens geometry and mechanical properties for the mechanics of accommodation and the role of these elements in the causes and potential correction of presbyopia. Setting: Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, USA. Design: Experimental study. Methods: Finite element methods and ray-tracing algorithms were used to model the deformation and optical power of the human crystalline lens during accommodation. The mechanical model treats the lens as an axisymmetric object, and the optical model incorporates a gradient refractive index. Using these models, the accommodation of a broad range of lenses with different geometries and mechanical properties were investigated. Results: The most significant result was that reshaping the 45-year-old lens to the geometry of the 29-year-old lens, while retaining the mechanical properties, restored the former's accommodation amplitude to 72% to 94% of that of the 29-year-old lens, depending on ciliary body displacement. That is, reshaping can add 1.8 to 3.7 diopters of accommodation. A sensitivity analysis showed that this result was robust over a wide range of mechanical and geometrical properties. Conclusion: The study results suggest that a significant amount of the loss of accommodation is due to changes in lens geometry. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.
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U2 - 10.1016/j.jcrs.2010.09.001
DO - 10.1016/j.jcrs.2010.09.001
M3 - Article
C2 - 21029906
AN - SCOPUS:78049276335
SN - 0886-3350
VL - 36
SP - 1960
EP - 1971
JO - Journal of Cataract and Refractive Surgery
JF - Journal of Cataract and Refractive Surgery
IS - 11
ER -