Comparison Of Corneal Biomechanics In Post-Smile, Post-Lasek, And Normal Eyes With Brillouin Microscopy

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

Fudan University Eye & ENT Hospital, China

A total of 177 eyes (79 post-SMILE, 24 post-LASEK, and 74 normal eyes) from 177 myopic patients underwent Pentacam HR and Brillouin microscopy measurements. Mean differences among the groups were assessed by analysis of variance. Paired-sample t-tests were used to evaluate the Brillouin metric differences pre- and post-operatively for within-subject comparisons. The correlation between clinical parameters and Brillouin modulus (BM) was analyzed using the Variance Inflation Factor (VIF) method and multiple linear regression.

No 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 LASEK groups, while Max–Min BM significantly increased. In post-SMILE corneas, Std BM was significantly higher than in normal Within-subjects comparisons. Multiple linear regression analysis revealed a negative correlation between Central BM and post-operative corneal thickness in post-SMILE corneas (coefficient=–0.016). In the post-LASEK group, Max-Min BM showed a positive correlation with K_mean (coefficient=0.031). In the within-subject comparison of eyes after SMILE, changes in Central BM and time after surgery were negatively correlated (coefficient=–0.043).

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

Mean BM have emerged as a reliable Brillouin metric.