Comparison of Changes in Corneal Thickness and Curvature After Myopia Correction Between SMILE and FS-LASIK

Abstract

Purpose:

To comparatively investigate the changes in corneal thickness and curvature between small incision lenticule extraction (SMILE) and femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK).

Methods:

Data were collected preoperatively and postoperatively at 1 week, 1 month, and 3 months, including central corneal thickness (CCT), midperipheral corneal thickness (MPCT), peripheral corneal thickness (PCT), central keratometry (CK), midperipheral keratometry (MPK), and peripheral keratometry (PK), using a dual rotating Scheimpflug analyzer.

Results:

At 1 week postoperatively, changes in CCT, MPCT, PCT, and PK were significantly greater in the SMILE group than in the FS-LASIK group ( P = .003 for CCT and < .001 for MPCT, PCT, and PK), but no significant inter-group differences were found between changes in CK and MPK ( P = .883 and .513, respectively). CCT, MPCT, and PK values showed a similar increase in both groups, but significantly more increase in PCT and significantly less increase in CK and MPK was observed in the SMILE group from 1 week to 3 months after surgery. At 3 months postoperatively, CCT and MPCT were significantly thinner in the SMILE group than in the FSLASIK group ( P = .018 and .022, respectively), and there was no significant difference in PCT, CK, MPK, and PK between the two groups.

Conclusions:

SMILE caused significantly more corneal thinning at the center, midperiphery, and periphery, and more corneal flattening at the periphery, compared to FS-LASIK. A different pattern of corneal remodeling was observed between the two surgeries during the 3-month follow-up period.

[ J Refract Surg . 2023;39(1):15–22.]