Numerical Simulation for the Safe Retention Value of Residual Stromal Bed Thickness in Laser-Assisted in situ Keratomileusis
10.16156/j.1004-7220.2020.06.12
- VernacularTitle:LASIK手术剩余基质床厚度安全保留值的数值模拟
- Author:
Zhichao DONG
1
;
Zhipeng GAO
2
;
Xiaogang WU
2
;
Yu CHEN
1
;
Wentao JIANG
1
Author Information
1. Department of Mechanics and Engineering, Sichuan University
2. College of Biomedical Engineering, Taiyuan University of Technology
- Publication Type:Journal Article
- Keywords:
keratoconus;
glaucoma;
corneal flap;
apical displacement;
curvature radius;
tensile stress
- From:
Journal of Medical Biomechanics
2020;35(6):E725-E731
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the effects of different residual stromal bed thickness (RSBT) in laser-assisted in situ keratomileusis (LASIK) surgery on geometric deformation and stress changes of the cornea under different intraocular pressures (IOP), and evaluate safety of the three retention values (250, 280, 300 μm). Methods The models of normal cornea and corneas with different RSBT after surgery were established by the finite element software ABAQUS. Appropriate loading and boundary conditions were set and then the corresponding displacement and stress were calculated. Results The apical displacement of the postoperative cornea (RSBT=250 μm) under IOP=2.66 kPa was basically the same as that of the normal cornea (RSBT=550 μm) under IOP=5.32 kPa. RSBT=280 μm was in the low risk area of keratoconus, while RSBT=250 μm was in the high-risk area. At a value between 280 μm and 300 μm of RSBT, the stress distribution was nearly consistent with that of the normal cornea. With RSBT=300 μm, the stromal layer of the cornea lost 40% of the strongest strength against tissue tension. Conclusions RSBT=250 μm is the minimum retention value for LASIK surgery. RSBT=250 μm is the high risk value. With RSBT=330-340 μm, LASIK surgery is safe enough for most patients.
