AIM: To compare the effective optical zone(EOZ)and corneal high order aberrations(HOAs)after small incision lenticule extraction(SMILE)among low, moderate, and high myopic patients.

METHODS:A total of 134 patients who had undergone SMILE at the Second People's Hospital of Foshan from February 2019 to February 2021 were recruited, with all right eyes enrolled. The patients were divided into low myopia group(SE >-3.00 D), moderate myopia group(-6.00 D< SE ≤-3.00 D), and high myopia group(SE ≤-6.00 D)according to the spherical equivalent(SE). The total HOA(tHOA), spherical aberration, coma, and EOZ were measured by Pentacam preoperatively and 1 mo postoperatively, and differences in tHOA, spherical aberration, coma, and EOZ among the three groups were analyzed.

RESULTS: EOZ was smaller than programmed EOZ in all groups at 1 mo after SMILE. With the increase in corrected refractive error, the EOZ decreased further(P<0.05); The tHOA, spherical aberration, and coma were significantly higher than their corresponding preoperative values in all groups at 1 mo after surgery, and there were statistical differences in the spherical aberration of all the groups at 1 mo after surgery(P<0.05), except for that of the mild myopia group(P>0.05). The tHOA, spherical aberration and coma increased with corrected refractive errors; the difference in tHOA and spherical aberration was statistically significant among the three groups(all P<0.05). Coma in the high myopia group was significantly greater than that in the moderate myopia group and the mild myopia group(P<0.05). In addition, the coma in the moderate myopia group and the mild myopia group was not statistically significant(P>0.05).

CONCLUSION: With the increase of the refractive power corrected by surgery, the postoperative EOZ reduced more after surgery, and the HOA of the cornea is increased; corneal HOA increases at 1 mo after SMILE.