Study on establishment and mechanics application of finite element model of bovine eye

BMC Ophthalmology

Research Article

Kun Xiong¹  Yan-Hui Cui¹  Lei Shang¹  Ju-Fang Huang¹  Si-Ying Cheng²  Wei Wei³  Na Li⁴ 

[1] Department of Anatomy and Neurobiology, Morphological Sciences Building, Central South University, 172 Tongzi Po Road, 410013, Changsha, Hunan, China;Eight-year clinical medicine, 2011 grade, Xiangya Medical School, Central South University, 410013, Changsha, Hunan, China;Laboratoire de Biomécanique Appliquée, MRT24 IFSTTAR-Aix-Marseille Université, Bd. P. Dramard, Faculté de Medecine secteur-Nord, 13916, Marseille, France;Radiology Department, Third Xiangya Hospital, Central South University, 138 Tongzi Po Road, 410013, Changsha, Hunan, China;

关键词: High increased intraocular pressure;    Sclera;    Lamina cribrosa;    Finite element modeling;   

DOI  :  10.1186/s12886-015-0073-4

 received in 2014-11-14, accepted in 2015-07-14,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundGlaucoma mainly induced by increased intraocular pressure (IOP), it was believed that the pressure that wall of eyeball withstands were determined by material properties of the tissue and stereoscopic geometry of the eyeball. In order to study the pressure changes in different parts of interior eyeball wall, it is necessary to develop a novel eye ball FEM with more accurate geometry and material properties. Use this model to study the stress changes in different parts of eyeball, especially the lamina cribrosa (LC) under normal physiological and pathological IOP, and provide a mathematical model for biomechanical studies of selected retinal ganglion cells (RGCs) death.Methods(1) Sclera was cut into 3.8-mm wide, 14.5-mm long strips, and cornea was cut into 9.5-mm-wide and 10-mm-long strips; (2) 858 Mini BionixII biomechanical loading instrument was used to stretch sclera and cornea. The stretching rate for sclera was 0.3 mm/s, 3 mm/s, 30 mm/s, 300 mm/s; and for cornea were 0.3 mm/s and 30 mm/s. The deformation-stress curve was recorded; (3) Naso-temporal and longitudinal distance of LC were measured; (4) Micro-CT was used to accurately scan fresh bovine eyes and obtain the geometrical image and data to establish bovine eye model. 3-D reconstruction was performed using these images and data to work out the geometric shape of bovine eye; (5) IOP levels for eyeball FEM was set and the inner wall of eyeball was used taken as load-bearing part. Simulated eyeball FE modeling was run under the IOP level of 10 mmHg, 30 mmHg, 60 mmHg and 100 mmHg, and the force condition of different parts of eyeball was recorded under different IOP levels.Results(1) We obtained the material parameters more in line with physiological conditions and established a more realistic eyeball model using reversed engineering of parameters optimization method to calculate the complex nonlinear super-elastic and viscoelastic parameters more accurately; (2) We observed the following phenomenon by simulating increased pressure using FEM: as simulative IOP increased, the stress concentration scope on the posterior half of sclera became narrower; in the meantime, the stress-concentration scope on the anterior half of scleral gradually expanded, and the stress on the central part of LC is highest.ConclusionAs simulative IOP increased, stress-concentration scope on the posterior half of sclera gradually narrowed; in the meantime, the stress-concentration scope on the anterior half of sclera gradually expanded, and the stress on the LC is mainly concentrated in the central part, suggesting that IOP is mainly concentrated in the anterior part of the eyeball as it increases. This might provide a biomechanical evidence to explain why RGCs in peripheral part die earlier than RGCs in central part under HIOP.

【 授权许可】

Unknown   
© Cui et al. 2015. This article is published under license to BioMed Central Ltd. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.