Comparison of corneal biomechanics in post-smile, post-LASEK, and normal eyes with Brillouin microscopy

J Optom. 2025 Oct-Dec;18(4):100579. doi: 10.1016/j.optom.2025.100579. Epub 2025 Aug 26.

ABSTRACT

PURPOSE: To characterize corneal biomechanics in post-small-incision lenticule extraction (SMILE), post-laser-assisted subepithelial keratomileusis (LASEK), and normal eyes using Brillouin microscopy.

METHODS: This study included myopic patients who underwent corneal refractive surgery (SMILE or LASEK) at least 1 month prior to ensure corneal stability. A total of 177 eyes (79 post-SMILE, 24 post-LASEK, and 74 untreated normal eyes) from 177 patients were evaluated using Pentacam HR and Brillouin microscopy for morphological and biomechanical assessment, respectively. Among them, 30 eyes (20 post-SMILE and 10 post-LASEK) from 30 participants underwent both pre- and post-operative Brillouin and Pentacam examinations, enabling within-subject comparisons. Corneal biomechanics were assessed using Brillouin modulus (BM), where lower values indicate weaker biomechanical properties.

RESULTS: No significant differences were observed in Central BM, Mean BM, or Max BM among the groups. Compared with the normal eyes, Min BM was significantly lower in the post-SMILE and post-LASEK groups (P = 0.004 and 0.002, respectively) and Max-Min BM significantly increased after SMILE and LASEK (both P < 0.001). In post-SMILE corneas, standardized deviation BM was significantly higher than in normal corneas (P < 0.001). Within-subjects comparisons (pre- vs post-operation) further confirmed above results. Multiple linear regression analysis revealed a negative correlation between Central BM and post-operative corneal thickness in post-SMILE corneas (coefficient = -0.016, P = 0.025). In the post-LASEK group, Max-Min BM showed a positive correlation with mean corneal curvature (coefficient = 0.031, P = 0.001).

CONCLUSION: SMILE and LASEK can induce localized changes in corneal biomechanics, as observed by Brillouin microscopy, while maintaining overall corneal biomechanics.

PMID:40865157 | PMC:PMC12409421 | DOI:10.1016/j.optom.2025.100579