[Early outcomes of corneal sensitivity changes after small incision lenticule extraction and femtosecond lenticule extraction].

Abstract

To evaluate and compare the recovery of central and peripheral corneal sensitivity in the early period after small incision lenticule extraction (SMILE) and femtosecond lenticule extraction (FLEx). In this study, 47 cases (87 eyes) which underwent SMILE and FLEx were included. Central, superior, inferior, nasal and temporal corneal sensitivity was measured using a Cochet-Bonnet esthesiometer (Luneau Ophthalmologic) before and 1 week, 1 month, and 3 months after SMILE and FLEx. The results were analyzed with Mann-Whitney test by SPSS13.0 software. There were statistical differences between SMILE and FLEx group in the central, inferior, nasal and temporal corneal sensitivity at 1 week, 1 month and 3 months postoperatively (Z = -5.219, -7.120, -6.735, -7.139, -5.945, -6.644, -7.006, -7.121, -5.262, -3.086, -4.140, -3.523. P < 0.01). However, the superior corneal sensitivity in the SMILE group did not show significant difference (Z = -1.807, P = 0.071) as compared to FLEx group (with exception of 1 week postoperatively). At 1 month and 3 months postoperatively, corneal sensitivity in the superior quadrant were (5.23 ± 0.62) and (5.57 ± 0.57) cm in the SMILE group, and were (4.43 ± 1.20) and (4.85 ± 1.11) cm in the FLEx group. There were statistical differences between these two groups (Z = -2.935, -2.678. P = 0.003, 0.007). In the SMILE group, corneal sensitivity in the central, superior, inferior, nasal and temporal quadrants at 3 months postoperatively was (5.74 ± 0.51), (5.57 ± 0.57), (5.70 ± 0.55), (5.83 ± 0.37), (5.84 ± 0.30) cm respectively, there were no significant differences as compared with preoperative data (Z = -1.255, -0.893, -0.570, -0.630, -0.935. P = 0.209, 0.440, 0.569, 0.529, 0.350). In the FLEx group, corneal sensitivity in the superior at 3 months postoperatively was 4.85 ± 1.11, there was not significant difference compared with preoperative data (Z = -1.095, P = 0.272). There were no correlations between the changes of central corneal sensitivity and central corneal ablation depth, central corneal thickness and preoperative spherical equivalent (SMILE group: r = 0.159, -0.202, 0.106, 0.060. P > 0.05. FLEx group: r = -0.156, -0.059, 0.058, -0.005. P > 0.05) after SMILE and FLEx surgery. Corneal sensitivity decreases after SMILE and FLEx, and then returns to its original state over time. The decrease of corneal sensitivity after the SMILE was fewer and the recovery was faster as compared with FLEx.