AIM:To observe the effects of small incision lenticule extraction(SMILE)and trans-epithelial photorefractive keratectomy(Trans-PRK)on corneal horizontal coma, vertical coma, and spherical aberration and total higher order aberrations after refractive correction for myopia.

METHODS: This was a prospective non-randomized cohort study. The cohort included 40 patients(80 eyes)with myopia, who received refraction correction surgery from December 2016 to February 2017 in Leshan Ophthalmic Center. Twenty patients(40 eyes)received SMILE surgery and the other 20 patients(40 eyes)received Trans-PRK surgery. Corneal aberrations were determined by a high-resolution Pentacam Scheimpflug camera before the surgery and at 1 and 3mo after the operation. Statistical analyses were performed using analysis of variance of repeated measures.

RESULTS: At 1 and 3mo post-operation, the uncorrected visual acuity in both groups was better than or equal to the preoperative best corrected visual acuity. The preoperative corneal aberrations showed no significant difference between the two groups(P>0.05). Significantly higher aberration was found after the surgery in both groups(P<0.05), however, no significant difference in higher aberration was found between 1 and 3mo post-operation(P>0.05). Post-operation, horizontal and vertical coma had no significant difference between the two groups(P>0.05), while SMILE group showed lower spherical aberration and lower total higher order aberration than Trans-PRK group(P<0.05).

CONCLUSION: Both SMILE and Trans-PRK increase corneal aberration and their effects on horizontal and vertical coma are similar. However, SMILE has a minor influence on spherical aberration and total high order aberration than Trans-PRK.