Microstructure visualization of conventional outflow pathway and finite element modeling analysis of trabecular meshwork.
BACKGROUND
The intraocular pressure (IOP) is maintained through a dynamic equilibrium between the production and drainage of aqueous humor. Elevation of intraocular pressure is mainly caused by the blocking of aqueous humor outflow pathway. Therefore, it is particularly important to study the structure of drainage pathway and the effect of ocular hypertension at the process of aqueous humor outflow.


METHODS
Conventional drainage pathway of aqueous humor, including trabecular meshwork (TM), Schlemm's canal (SC) and aqueous vein, were imaged by using trans-scleral imaging method with lateral resolution of 2 μm. For quantitative assessment, the morphological parameters of the TM were measured with different IOP levels via a combination of measurements and simulations.


RESULTS
Images of the TM and the adjacent tissues were obtained. The porosity of TM with normal intraocular pressure varies from 0.63 to 0.74 as the depth increases, while in high IOP it is changed from 0.44 to 0.59. The diameter of aqueous vein varies from 32 to 43 μm, and is smaller than that of SC, which varies from 48 to 64.67 μm.


CONCLUSIONS
Our research provides a non-contact method to visualize the microstructure of tissue for clinical examination associated with the blocking of the outflow pathway of aqueous humor in humans. The three-dimensional (3D) microstructures of limbus and the results of finite element modeling analysis of the TM model will serve for the future evaluation of new glaucoma surgical techniques.
School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.|Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
Jing
J
Zhang
School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.|Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
Lin
L
Ren
School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.|Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
Xi
X
Mei
Shenzhen Key Lab for Molecular Imaging, Research Lab for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
Qiang
Q
Xu
Shenzhen Key Lab for Molecular Imaging, Research Lab for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China. zhengwei@siat.ac.cn.
Wei
W
Zheng
School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. zcliu@ccmu.edu.cn.|Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China. zcliu@ccmu.edu.cn.
Zhicheng
Z
Liu
D000818:Animals; D001082:Aqueous Humor / Q000502:physiology*; D003198:Computer Simulation; D020342:Finite Element Analysis; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007429:Intraocular Pressure; D008833:Microcirculation; D008955:Models, Cardiovascular; D016062:Porosity; D051381:Rats; D012590:Sclera / Q000503:physiopathology; D014065:Tonometry, Ocular / Q000379:methods*; D014129:Trabecular Meshwork / Q000502:physiology*
3D reconstruction; Conventional outflow pathway; Finite element modeling; Porosity; Trans-scleral imaging method