Time-varying regularity of changes in biomechanical properties of the corneas after removal of anterior corneal tissue

Di Zhang; Xiao Qin; Haixia Zhang; Lin Li

doi:10.1186/s12938-021-00948-7

Time-varying regularity of changes in biomechanical properties of the corneas after removal of anterior corneal tissue

Biomed Eng Online. 2021 Nov 20;20(1):113. doi: 10.1186/s12938-021-00948-7.

Authors

Di Zhang^{1

2}, Xiao Qin^{1

2}, Haixia Zhang^{3

4}, Lin Li^{5

6}

Affiliations

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 School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. zhanghx@ccmu.edu.cn.
⁴ Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China. zhanghx@ccmu.edu.cn.
⁵ School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. lil@ccmu.edu.cn.
⁶ Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China. lil@ccmu.edu.cn.

Abstract

Background: The corneal biomechanical properties with the prolongation of time after corneal refractive surgery are important for providing a mechanical basis for the occurrence of clinical phenomena such as iatrogenic keratectasia and refractive regression. The aim of this study was to explore the changes of corneal elastic modulus, and stress relaxation properties from the 6-month follow-up observations of rabbits after a removal of anterior corneal tissue in simulation to corneal refractive surgery.

Methods: The anterior corneal tissue, 6 mm in diameter and 30-50% of the original corneal thickness, the left eye of the rabbit was removed, and the right eye was kept as the control. The rabbits were normally raised and nursed for 6 months, during which corneal morphology data, and both of corneal hysteresis (CH) and corneal resistance factor (CRF) were gathered. Uniaxial tensile tests of corneal strips were performed at months 1, 3, and 6 from 7 animals, and corneal collagen fibrils were observed at months 1, 3, and 6 from 1 rabbit, respectively.

Results: Compared with the control group, there were statistical differences in the curvature radius at week 2 and month 3, and both CH and CRF at months 1, 2, and 6 in experiment group; there were statistical differences in elastic modulus at 1, 3, and month 6, and stress relaxation degree at month 3 in experiment group. The differences in corneal elastic modulus, stress relaxation degree and the total number of collagen fibrils between experiment and control groups varied gradually with time, and showed significant changes at the 3rd month after the treatment.

Conclusions: Corneas after a removal of anterior corneal tissue undergo dynamic changes in corneal morphology and biomechanical properties. The first 3 months after treatment could be a critical period. The variation of corneal biomechanical properties is worth considering in predicting corneal deformation after a removal of anterior corneal tissue.

Keywords: Corneal elastic modulus; Corneal refractive surgery; Stress relaxation; Uniaxial tests.

MeSH terms

Animals
Biomechanical Phenomena
Computer Simulation
Cornea* / surgery
Elastic Modulus
Rabbits

Abstract

MeSH terms

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