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

- Posterior corneal elevation (PCE) changes and corneal biomechanical parameters were evaluated for SMILE and FS-LASIK.
- PCE change in FS-LASIK was greater than SMILE at 12 months post-operation.
- CH and CRF were reduced for both procedures at 6 and 12 months, FS-LASIK demonstrated a greater reduction in CRF than SMILE.
- PCE was moderately correlated with CH and CRF change, indicating an increase in PCE with greater reduction in CH and CRF.

PurposeTo 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).DesignRetrospective observational case series study.Method106 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.ResultsPCE 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.ConclusionFS-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.