OK镜对不同曲率的非对称角膜生物力学特性的有限元分析

Finite Element Analysis of the Biomechanical Effects of Orthokeratology Lenses on Asymmetric Corneas with Different Curvatures

摘要: 目的：探究非球面角膜塑形镜(OK镜)设计对非对称角膜生物力学影响的差异，以揭示OK镜影响角膜塑形的作用机制。方法：基于角膜非对称结构和上海微创视神医疗科技有限公司合作提供的OK镜设计参数，建立非球面的OK镜–非对称角膜耦合的三维有限元模型，探究OK镜对不同曲率角膜的生物力学性能的影响。结果：角膜前表面最大应力集中区域主要分布于角膜周围区，且在水平和垂直方向上表现出明显的非对称性分布趋势。OK镜基弧的矢高随着角膜曲率的增加而减小，角膜曲率为40D~46D时，角膜最大应力值分别为2938.96 Pa、3203.27 Pa、3419.34 Pa、3036.08 Pa、3749.45 Pa、3766.77 Pa和3685.22 Pa。结论：OK镜的基弧区对角膜中央变平和中周区变陡起作用。且角膜曲率越大，压平效果越好。这一发现强调了在OK镜设计与临床验配过程中，必须充分考虑角膜的非对称生物力学特性，以实现更精准的屈光矫正效果并优化视觉质量。研究结果为OK镜的个性化设计与临床应用提供了重要的理论依据。

Abstract: Objective: To investigate the differences in the biomechanical effects of aspheric orthokeratology (OK) lens design on asymmetric corneas and to elucidate the mechanisms by which OK lenses influence corneal reshaping. Methods: A three-dimensional finite element model of aspheric OK lens-asymmetric cornea coupling was established based on the asymmetric structure of the cornea and the OK lens design parameters provided by MicroVision Medical Technology Co., Ltd. (Shanghai). This model was used to explore the biomechanical effects of OK lenses on corneas with different curvatures. Results: The maximum stress concentration on the anterior corneal surface was primarily distributed in the peripheral zone, exhibiting a significant asymmetric distribution trend in both horizontal and vertical directions. He sagittal height of the base curve of the OK lens decreased with increasing corneal curvature, with maximum stress values of 2938.96 Pa, 3203.27 Pa, 3419.34 Pa, 3036.08 Pa, 3749.45 Pa, 3766.77 Pa, and 3685.22 Pa for corneal curvatures ranging from 40D to 46D. Conclusion: The base curve of the OK lens contributes to the flattening of the central cornea and the steepening of the mid-peripheral region. Moreover, the flattening effect becomes more pronounced with higher corneal curvature. This finding underscores the necessity of considering the asymmetric biomechanical properties of the cornea in the design and clinical fitting of OK lenses to achieve more precise refractive correction and optimize visual quality. The results provide important theoretical insights for the personalized design and clinical application of OK lenses.