Comparison of the change in posterior corneal elevation and corneal biomechanical parameters after small incision lenticule extraction and femtosecond laser-assisted LASIK for high myopia correction.

Abstract Purpose To compare posterior corneal elevation (PCE) changes and corneal biomechanical changes post fematosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) procedures using the Pentacam system and the Ocular Response Analyzer (ORA). Design Retrospective observational case series study. Method 106 patients with bilateral myopia who underwent either FS-LASIK (56 patients) or SMILE (50 patients) were reviewed, only the right eye was used in the analysis. Inclusion criteria include a spherical equivalent of −6.00DS and completion of 12 months follow up. The main outcome evaluated was change in PCE at 3 months, 6 months and 12 months post-operation using the Pentacam system. Corneal biomechanical parameters were evaluated at 6 and 12 months with the ORA. Results PCE change at 3 and 6 months were not significantly different between the two procedures ( p  = 0.064, p  = 0.109 respectively). At 12 months, PCE change was greater in FS-LASIK than SMILE ( p  = 0.048). One-way ANOVA showed that for either procedure, the change in PCE did not differ at 3, 6 or 12 months post operation. CH and CRF values were reduced after both procedures, with FS-LASIK demonstrating a greater reduction in CRF than SMILE at 6 and 12 months ( p  = 0.037 and p  = 0.001). Both CH and CRF reduction correlated with PCE increase at 6 and 12 months. Conclusion FS-LASIK demonstrated a greater increase in PCE than SMILE only at 12 months, as well as a greater reduction of CRF than SMILE. There were no significant differences in PCE change over time within either group.