Wavefront analysis and comparison between small incision lenticule extraction and femtosecond laser in situ keratomilensis

Abstract

To investigate and analyze the characteristic changes of high order aberrations before and after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK). Prospective study. Thirty-four patients (16 men and 18 women) underwent SMILE, and 28 cases (15 men and 13 women) underwent FS-LASIK, aged 18 to 39 years. Only the right eye was selected to be analyzed from each patient. All patients had conventional and Pentacam examinations preoperatively, and the ocular higher order aberrations were measured with the Hartman-Shack wavefront analyzer before surgery and at 1 month and 3 months postoperatively. The paired t test, independent t test, and Pearson correlation analysis were used to analyze the collected data. At the 1 month after SMILE group, C3(-1), C3(3) (-0.205 +/- 0.199, 0.027 +/- 0.071) were higher than the FS-LASIK group (0.004 +/- 0.316, -0.022 +/- 0.104) (t = -3.141, 2.216, P < 0.05), for FS-LASIK group Sh, S4 S5, S6, C4(0) (0.609 +/- 0.199, 0.403 +/- 0.196, 0.117 +/- 0.065, 0.092 +/- 0.038, 0.343 +/- 0.253) were higher than the SMILE group (0.461 +/- 0.130, 0.271 +/- 0.096, 0.074 +/- 0.028, 0.053 +/- 0.018, 0.239 +/- 0.121) (t = - 3.492, -3.461, -3.449, -5.301, -2.103, P < 0.05); At the 3rd month of SMILE group, C3(-1) (-0.177 +/- 0.175) was higher than the FS-LASIK group (-0.012 +/- 0.337) (t = -2.476, P < 0.05), In FS- LASIK group , however, the data for Sh, S4, S5, S6, C4(0) (0.626 +/- 0.215, 0.421 +/- 0.200, 0.108 +/- 0.066, 0.082 +/- 0.036, 0.393 +/- 0.207) were higher than the SMILE group (0.457 +/- 0.113, 0.270 +/- 0.106,0. 082 +/- 0.031, 0.051 +/- 0.017, 0.243 +/- 0.115 ) (t = -3.935, -3.788, -2.049, -4.405, -3.576, P < 0.05). With the correlation analysis, at the postoperative 1st and 3rd month of FS-LASIK group, Sh, C4(0) had negative relationship with the attempted myopic corrections (1 month post-op: r = - 0.433, -0.476, P < 0.05; 3 month post-op:r = -0.418, -0.447, P < 0.05). SMILE resulted in good optical quality early after operation. Compared with FS-LASIK, SMILE caused smaller change of ocular higher order aberrations, and each of them had its own particularity. Maybe it was associated with the surgery procedure and corneal wound healing after surgery.