Comparison of the corneal biomechanical effects after small-incision lenticule extraction and Q value guided femtosecond laser-assisted laser <i>in situ</i> keratomileusis

AIM:By comparing the changes of biomechanical properties of the cornea after small-incision lenticule extraction(SMILE)and those after Q value guided femtosecond laser-assisted laser <i>in situ</i> keratomileusis(FSLASIK), to study the stability of biomechanical properties of the cornea after these two kinds of surgery and provide objective data for clinical operation.<p>METHODS: Prospective comparative cases. One hundred and two cases(200 eyes)with myopia and myopic astigmatism were divided into 2 groups, 51 cases(100 eyes)for SMILE, and 51 cases(100 eyes)for Q value guided FS-LASIK. Corneal hysteresis(CH)and the corneal resistance factor(CRF)were quantitatively assessed with the Ocular Response Analyzer(ORA)preoperatively and 1d, 2wk, 1 and 3mo postoperatively.<p>RESULTS: The decrease in CH and the CRF were statistically significant in both groups(<i>P</i><0.01). However, the changes subsequently stabilized with no further deterioration(<i>P</i>>0.05). There were no statistically significant differences between the biomechanical changes in the two groups at any time(<i>P</i>>0.05).<p>CONCLUSION: Both SMILE and Q value guided FS-LASIK can cause biomechanical decreases in the cornea. After 1d postoperatively, the decreases are nearly stable. There are no significant differences between the effect of SMILE and Q value guided FS-LASIK on the biomechanical properties of the cornea