Wave front aberrations induced from biomechanical effects after customized myopic laser refractive surgery in finite element model

Abstract

A customized myopic refractive surgery was simulated by establishing a finite element model of the human eye,after which we studied the wavefront aberrations induced by biomechanical effects and ablation profile after wavefrontguided LASIK surgery.Methods: Thirty myopia patients (i.e., 60 eyes) without other eye diseases were selected. Their ages, preoperative spherical equivalent, astigmatism, and wavefront aberration were then obtained, in addition to the mean spherical equivalent error range -4 to -8D. Afterward, wavefront-guided customized LASIK surgery was simulated by establishing a finite element eye model, followed by the analysis of the wavefront aberrations induced by the surface displacement from corneal biomechanical effects, as well as customized ablation profile. Finally, the preoperative and induced aberrations were statistically analyzed.Results: Comatic aberrations were the main wavefront abnormality induced by biomechanical effects, and the wavefront aberrations induced by the ablation profile mainly included coma and secondary-coma, as well as sphere and secondarysphere aberrations. Overall, the total high-order aberrations (tHOAs), total coma (C 31 ), and sphere ( 0 4 C ) increased after wavefront-guided customized LASIK surgery. According to our correlation analyses, coma, sphere, and total high-order aberrations were significantly correlated with decentration. Additionally, the material parameters of ocular tissue were found to affect the postoperative wavefront aberrations. When the material parameters of the sclera remained constant but those of cornea increased, the induced wavefront aberrations were reduced. Conclusion:All biomechanical effects of cornea and ablation profile had significant effects on postoperative wavefront aberrations after customized LASIK refractive surgery; however, the effects of the ablation profile were more notorious.Additionally,the characteristics of biomechanical materials have influence on the clinical correction effect.

Clinical outcomes and higher order aberrations of wavefront‐guided LASIK versus SMILE for correction of myopia: A systemic review and meta‐analysis

“…Moreover, the influence of corneal biomechanics and wound healing on spherical aberration cannot be ignored. HOAs are associated with biomechanical weakness of the cornea (Du et al, 2022; Fang et al, 2020). SMILE retains better mechanical properties than LASIK, which also explains the smaller spherical aberration introduced after SMILE (Guo et al, 2019).…”

Changes in Corneal Epithelial Thickness in Relation to Vision, Contrast Sensitivity and Ocular Aberrations After Lasik

“…Researches has shown that increased coma is associated with corneal flap creation and small intraoperative eye movements [17,18]. Du, et al, reported that coma was the main aberration caused by corneal biomechanical changes [19]. One of the limitations of our study is the small sample that was studied.…”