Numerical study of critical straight, frown, and chevron incisions in small incision cataract surgery

Yang Han; Nan Qi

doi:10.3389/fbioe.2023.1283293

Numerical study of critical straight, frown, and chevron incisions in small incision cataract surgery

Front Bioeng Biotechnol. 2023 Oct 20:11:1283293. doi: 10.3389/fbioe.2023.1283293. eCollection 2023.

Authors

Yang Han^{1

2}, Nan Qi^{1

3}

Affiliations

¹ Research Center for Mathematics and Interdisciplinary Sciences, Shandong University, Qingdao, Shandong, China.
² Institute of Marine Science and Technology, Shandong University, Qingdao, China.
³ Frontiers Science Center for Nonlinear Expectations, Shandong University, Qingdao, Shandong, China.

Abstract

Introduction: When an intraocular lens (IOL) injector is inserted through a pre-cut corneal incision (e.g., an empirical size of 2.2 mm) during small incision cataract surgery, uncontrollable tearing to the corneal tissue may occur, which is highly associated with the incision shape, size, and location. The goal of this numerical study was to investigate the optimal incision scheme amongst three typical shapes, i.e., straight, frown, and chevron incisions using mechanical modeling and finite element analysis. Methods: Assuming that the damage is caused by the tissue fracture at the incision tips and is governed by the classical energy release rate (ERR) theory which compares the current ERR value subject to IOL injection and the material's intrinsic parameter, critical ERR G _c. Results: It was found that for chevron incisions, the incision shape with an angle of 170° was superior which induced minimal ERR value, while for frown incisions, the shape with a central angle of 6° was optimal. Both chevron and frown incisions could allow a larger size of injector to inject through than a straight pre-cut. In particular, the frown incision performed the best due to its lowest corresponding ERR and easy operation. Discussion: It was also observed that regions where the embedded fibrils are more dispersed and exhibit high isotropy were more favorable. If necessary, the chevron incision was recommended to be more aligned with the direction exhibiting a larger modulus, for example, along the circumferential direction near the limbus. This study provides useful knowledge in operation design and a deep insight into mechanical damage to corneal wounds in small incision cataract surgery.

Keywords: chevron incision; energy release rate; finite element analysis; frown incision; small incision cataract surgery.

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. We gratefully acknowledge the financial support from the National Natural Science Foundation of China (No. 11902181).