Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia

[Purpose]: The modification of the mechanical properties of the human crystalline lens with age can be a major cause of presbyopia. Since these properties cannot be measured in vivo, numerical simulation can be used to estimate them. We propose an inverse method to determine age-dependent change in...

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Detalles Bibliográficos
Autores: Lanchares, Elena, Navarro, Rafael, Calvo, Begoña
Tipo de recurso: artículo
Fecha de publicación:2012
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/73613
Acceso en línea:http://hdl.handle.net/10261/73613
Access Level:acceso abierto
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spelling Hyperelastic modelling of the crystalline lens: Accommodation and presbyopiaLanchares, ElenaNavarro, RafaelCalvo, Begoña[Purpose]: The modification of the mechanical properties of the human crystalline lens with age can be a major cause of presbyopia. Since these properties cannot be measured in vivo, numerical simulation can be used to estimate them. We propose an inverse method to determine age-dependent change in the material properties of the tissues composing the human crystalline lens. [Methods]: A finite element model of a 30-year-old lens in the accommodated state was developed. The force necessary to achieve full accommodation in a 30-year-old lens of known external geometry was computed using this model. Two additional numerical models of the lens corresponding to the ages of 40 and 50 years were then built. Assuming that the accommodative force applied to the lens remains constant with age, the material properties of nucleus and cortex were estimated by inverse analysis. [Results]: The zonular force necessary to reshape the model of a 30-year-old lens from the accommodated to the unaccommodated geometry was 0.078 newton (N). Both nucleus and cortex became stiffer with age. The stiffness of the nucleus increased with age at a higher rate than the cortex. [Conclusions]: In agreement with the classical theory of Helmholtz, on which we based our model, our results indicate that a major cause of presbyopia is that both nucleus and cortex become stiffer with age; therefore, a constant value of the zonular forces with aging does not achieve full accommodation, that is, the accommodation capability decreases. © 2012 Spanish General Council of Optometry.The authors gratefully acknowledge the Instituto de Salud Carlos III (ISCIII) ahd the CIBER-BBN (Centro de Investigación Biomédica En Red en Bioingeniería, Biomateriales y Nanomedicina) initiative, and also the research support of the Spanish Ministry of Education and Science through the research projects DPI2008-02335 and FIS2008-00697.Peer ReviewedElsevier España2013201320122013info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501http://hdl.handle.net/10261/73613reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1016/j.optom.2012.05.006info:eu-repo/semantics/openAccessoai:digital.csic.es:10261/736132026-05-22T06:33:51Z
dc.title.none.fl_str_mv Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
title Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
spellingShingle Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
Lanchares, Elena
title_short Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
title_full Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
title_fullStr Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
title_full_unstemmed Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
title_sort Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia
dc.creator.none.fl_str_mv Lanchares, Elena
Navarro, Rafael
Calvo, Begoña
author Lanchares, Elena
author_facet Lanchares, Elena
Navarro, Rafael
Calvo, Begoña
author_role author
author2 Navarro, Rafael
Calvo, Begoña
author2_role author
author
description [Purpose]: The modification of the mechanical properties of the human crystalline lens with age can be a major cause of presbyopia. Since these properties cannot be measured in vivo, numerical simulation can be used to estimate them. We propose an inverse method to determine age-dependent change in the material properties of the tissues composing the human crystalline lens. [Methods]: A finite element model of a 30-year-old lens in the accommodated state was developed. The force necessary to achieve full accommodation in a 30-year-old lens of known external geometry was computed using this model. Two additional numerical models of the lens corresponding to the ages of 40 and 50 years were then built. Assuming that the accommodative force applied to the lens remains constant with age, the material properties of nucleus and cortex were estimated by inverse analysis. [Results]: The zonular force necessary to reshape the model of a 30-year-old lens from the accommodated to the unaccommodated geometry was 0.078 newton (N). Both nucleus and cortex became stiffer with age. The stiffness of the nucleus increased with age at a higher rate than the cortex. [Conclusions]: In agreement with the classical theory of Helmholtz, on which we based our model, our results indicate that a major cause of presbyopia is that both nucleus and cortex become stiffer with age; therefore, a constant value of the zonular forces with aging does not achieve full accommodation, that is, the accommodation capability decreases. © 2012 Spanish General Council of Optometry.
publishDate 2012
dc.date.none.fl_str_mv 2012
2013
2013
2013
dc.type.none.fl_str_mv info:eu-repo/semantics/article
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dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/73613
url http://hdl.handle.net/10261/73613
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1016/j.optom.2012.05.006
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier España
publisher.none.fl_str_mv Elsevier España
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
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