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O Stachs, H Martin, T Terwee, k Schmitz, RF Guthoff; 3d Ultrasound Biomicroscopy As A Basis For Fem Simulations Of The Accommodation Process . Invest. Ophthalmol. Vis. Sci. 2002;43(13):411.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Presbyopia is the most common refractive disturbance. The aim of this study was to investigate the benefit of 3D ultrasonic imaging in combination with FEM calculations to simulate accommodative processes. These experiments may provide further information about lens changes during accommodation and may led to a better understanding of the role of the lens and the ciliary body changes in the progression of the presbyopia. Methods: An ultrasound biomicroscope was modified in order to achieve computer-controlled movements of B-scan system in z-axis. After data collection the 3D-reconstruction was carried out using VoxelView. Custom-made software allows a contour analysis of the ciliary muscle. The ciliary muscle contour of different groups of volunteers was determined during various accommodation states. By these derived data and material properties from the literature the lens including the zonular fibres system was modeled using ABAQUS. Results: The three-dimensional presentation allows a extraction of the ciliary muscle from the ciliary body. We are able to distinguish and to analyse the changes in the muscle contour in different accommodation states. The calculation of the outer contours of the lens in accommodation and desaccommodation was performed using FEM with different boundary conditions. The change of optical power of the lens can be computed. Conclusion: The 3D ultrasound biomicroscopy allows an assessment of the individual ciliary muscle activity in consideration of the ciliary processes. In combination with a contour analysis tool we improved the muscle contour determination during different accommodation states. These data form a basis for FEM simulations using ABAQUS including lens, zonular system and ciliary body.
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