Meta-analysis of Corneal Biomechanical Effects after SMILE and FS-LASIK

Abstract

Background: To evaluate and compare corneal biomechanics after treatment of myopia using small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Methods: We performed a meta-analysis and searched for reports concerning corneal biomechanics after SMILE and FS-LASIK using MEDLINE, EMbase, CNKI and the Cochrane Library. The analysis included corneal hysteresis (CH) and corneal resistance factor (CRF) before and 3 months after the surgery. The quality of the reports was evaluated using the Newcastle-Ottawa scale (NOS). Statistical analysis was performed using RevMan5. Results: Only six studies with a total of 771 eyes were ultimately included in this meta-analysis, and the random effects model was adopted. The preoperative and three-month postoperative CH and CRF of SMILE and FS-LASIK were compared by the meta-analysis. No statistically significant difference was found in CH or CRF between the SMILE group and the FS-LASIK group before the surgery (WMD，-0.12; 95% CI，-0.31～0.06; P，0.19; WMD，-0.05; 95% CI，-0.29～0.19; P，0.69). There was no statistically significant difference in CH between the two surgical methods 3 months after the operation in the foreign group (WMD，0.19; 95% CI，-1.02～1.41; P，0.75) or in the Chinese group (WMD，0.13; 95% CI，-0.16～0.41; P，0.75). Likewise, no statistically significant difference was found in CRF between the two surgical methods in the foreign group 3 months after the operation (WMD，-0.11; 95% CI，-2.53～-2.31; P，0.93). Nevertheless, the difference in CRF between the two surgical methods was statistically significant in the Chinese group (WMD，0.26; 95% CI，0.06～0.47; P，0.01). Concusion: This meta-analysis indicated that SMILE showed no significant postoperative advantage in CH in comparison with FS-LASIK. For CRF, SMILE exhibited no obvious postoperative advantage in comparison with FS-LASIK in the foreign group, whereas SMILE was superior to FS-LASIK in the Chinese group.

Changes in Corneal Biomechanical Properties After Small-Incision Lenticule Extraction and Photorefractive Keratectomy, Using a Noncontact Tonometer

“…However, the high disparity among outcomes of the clinical studies aiming to compare corneal biomechanical behavior after SMILE with that of other surgical techniques have rendered this hypothesis to be controversial. 3,7,[11][12][13][14][15][16][17][18][19][20] With analysis of stromal tissue samples, Khamar et al 13 showed early molecular changes after SMILE and LASIK. They concluded that SMILE resulted in a better wound healing response, less stromal or nerve damage, and reduced postoperative complications compared with LASIK.…”