Preoperative Risk Factors of Keratometry, Myopia, Astigmatism, Age, and Sex for Myopic Regression After Laser-Assisted In Situ Keratomileusis, Photorefractive Keratectomy, and Keratorefractive Lenticule Extraction.

Purpose: The purpose of this study was to identify preoperative and demographic risk factors of myopic regression 1 year after corneal refractive surgery.

Methods: A retrospective study of 2093 patients (2781 eyes) who underwent laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), or small incision lenticule extraction (SMILE) and experienced myopic regression of ≥0.5 D 1 year after surgery was conducted.

Results: The incidence of regression at 1 year was higher in the overall SMILE group (10.1%) and steep keratometry group (9.6%) ( P < 0.05). SMILE eyes with normal (9.0%) and steep corneas (18.2%) had a higher incidence of regression than those of LASIK and PRK eyes ( P < 0.05). The mean magnitude of spherical equivalent (SEQ) regression for all regressed eyes was -0.63 ± 0.15 D. The overall SMILE group had a greater mean magnitude of spherical regression than the overall LASIK and PRK groups (-0.66 D vs. -0.48 D vs. -0.46 D, P < 0.05). There were no differences in cylindrical regression between any analyzed groups ( P > 0.05). Female status and SEQ predicted -0.034 D [(-0.051, -0.017), P < 0.001] and -0.012 D [(-0.018, -0.006), P < 0.001] of regression, respectively. Age and preoperative K m had an odds ratio for regression of 1.033 [(1.017, 1.049), P < 0.001] and 1.109 [(1.006, 1.221), P < 0.001], respectively.

Conclusions: Risk factors of myopic regression at 1 year included older age, female sex, steep corneas, and higher preoperative SEQ. SMILE had a higher incidence and greater magnitude of regression compared with LASIK and PRK.