The Biomechanics of Accommodation
Stachs O.1, Martin H.2, Guthoff R. F.1
1Augenklinik, Universität Rostock; 2Institut für Biomedizische Technik, Universität Rostock
Purpose: The aim of the study is the development of a biomechanical model for simlulation of accommodation and presbyopia.
Method: A finite elements model of the mechanism of accommodation is used, which contains the biomechanical properties of the lens with capsular bag, zonula and ciliary body. The model is based on literature data and own investigations using 3D- ultrasound biomicroscopy, TEM and Scheimpflug photograph. The deformation and the changes in power of the lens as well as the forces in the zonular insertion points under different conditions were calculated.
Results: The calculations result values for lens power, which correspond to the in vivo measurements. The shape of the lens in accommodation has an important influence on changes in lens power. The lens has to be modeled with nucleus, cortex and capsule in consideration of the material poperties.
Conclusions: The developed model reflects the physiological characteristics of accommodation and confirms the theorie of Helmholtz. The impact of different aging processes (lens stiffness, lens growing, changes in zonula and ciliary body) can be examined by an adjustment of the model.
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