A comparison of the diameters of different optical zones in higher order aberrations after small incision lenticule extraction (SMILE) surgery

Objective To investigate and analyze modifications to the diameters in different optical zones in higher order aberrations after small incision lenticule extraction surgery (SMILE). Methods Twenty-six patients (26 eyes) with a 6.0 mm optical zone diameter and 29 (29 eyes) with a 6.5 mm optical zone diameter were randomly included in a retrospective study. Only right eyes were investigated in the study. The higher order aberrations were measured with a WaveScan wavefront analyzer before surgery and at 1 month and 3 months postoperatively. A repeated measures analysis of variance and independent t test were used to analyze the collected data. Results At 1 month after SMILE, the total higher-order aberrations (HOA) and spherical aberrations in the 6.0 mm group, and the total HOA and coma in the 6.5 mm group were 0.273±0.098 μm, 0.100±0.077 μm, and 0.224±0.080 μm, 0.142±0.077 μm, which were higher than preoperative measurements (P 0.05) . Correlation analysis showed that lenticular thickness was positively correlated with HOA and coma in the 6.0 mm group and the HOA, coma and trefoil in the 6.5 mm group one month after surgery (r=0.502, 0.661, 0.672, 0.580, 0.383; P<0.05) . While at three months after surgery, lenticular thickness was positively correlated with HOA, coma and trefoil in the 6.0mm group and HOA in the 6.5 mm group (r=0.697, 0.629, 0.560, 0.501; P<0.05). Conclusion Different optical zones show various results in parts of high order aberrations (coma) in the early stage after SMILE surgery. This might be related to the specific principle of the surgery and the reaction to corneal wound healing. Key words: Small incision lenticule extraction; Myopia; Higher order aberrations; Optical zone; Lenticule thickness