Preliminary study on determination of mechanical parameters of cornea after refractive surgery based on inflation tests(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2018年第4期
- Page:
- 449-454
- Research Field:
- 医学生物物理
- Publishing date:
Info
- Title:
- Preliminary study on determination of mechanical parameters of cornea after refractive surgery based on inflation tests
- Author(s):
- ZHANG Di1; 2; Muhammad A. Khan3; 4; QIN Xiao1; 2; ZHANG Haixia1; 2; LI Lin1; 2; LIN Ding3; 4; LIU Zhicheng1; 2
- 1. School of Biomedical Engineering, Capital Medical University, Beijing 100069, China; 2. Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China; 3. Aier School of Ophthalmology, Central South University, Changsha 410015, China; 4. Changsha Aier Eye Hospital, Changsha 410015, China
- Keywords:
- ; laser in situ keratomileusis; corneal; inflation test; mechanical parameters; second order Ogden model; finite element method
- PACS:
- R318.01
- DOI:
- DOI:10.3969/j.issn.1005-202X.2018.04.015
- Abstract:
- Objective To explore a method for determining the mechanical parameters of cornea after refractive surgery with the use of finite element method based on the data of the corneal apex and the pressure obtained by in vitro inflation tests. Methods The left eyes of 4 New Zealand rabbits were the surgical eyes and their right eyes were the controls. Two rabbits were treated with standard laser in situ keratomileusis (LASIK), and for the other 2 rabbits, only LASIK flaps were created. The in vitro corneal inflation tests were performed at different time points after surgery. In the inflation test, corneal apex displacements, inner corneal surface pressures and corneal front profile images were obtained by displacement sensor, pressure sensor and microscope, separately. The inflation test was simulated by finite element method. In the simulated calculation, the corneal geometry model was constructed based on the obtained corneal profile images, and the second order Ogden model was used to describe the corneal constitutive relation. Finally, the corneal mechanical parameters were determined by comparing the experimental data with the calculated results. Moreover, the mechanical properties of the cornea were studied after the refractive surgery. Results Corneal apex displacements were nonlinear with the pressure. Under the same pressure, the corneal apex displacements of postoperative cornea were smaller than those of the controls. The second order Ogden model provided a good description of corneal mechanical properties after refractive surgery. The elastic moduli of the experimental eyes were larger than those of the controls. Conclusion Based on the experimental data of inflation tests, using finite element method to simulate corneal inflation tests and obtain mechanical parameters of cornea after refractive surgery is feasible.
Last Update: 2018-04-23