Predictors of Visual Acuity Improvement and Supernormal Vision After Refined Single-Step Transepithelial Photorefractive Keratectomy

PURPOSE: To investigate predicting factors of visual acuity improvement and achieving uncorrected (UDVA) or corrected (CDVA) distance visual acuity supernormal vision ( 15/10; Snellen 20/13) 1 year after refined transepithelial photorefractive keratectomy (TransPRK). METHODS: In this retrospective case series, a total of 155 eyes with myopia (mean +/- standard deviation = -3.53 +/- 1.81 diopters) with and without astigmatism (range = 0.25 to 4.50 diopters) were recruited and observed for 1 year. Patients underwent refined single-step TransPRK using the SCHWIND AMARIS 500 laser (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany). The main predicting factors of postoperative supernormal vision and visual acuity improvements were sought by statistical modeling. RESULTS: Logistic models showed mesopic contrast sensitivity, high laser fluence, and coma higher-order aberration (HOA) as predicting factors for both UDVA and CDVA super-normal vision. Myopia, astigmatism, dynamic cyclotorsion correction, optical zone, and transitional zone showed associations only in simple models and were not retained in multivariable models. According to the linear regression models, CDVA, mesopic contrast sensitivity, coma HOA, and keratometry were common predictors of both postoperative UDVA and CDVA improvement compared to preoperative UDVA. Astigmatism, optical and transitional zones, and high laser fluence were common predictors only in simple regression models. CONCLUSIONS: Through statistical modeling, preoperative CDVA, mesopic contrast sensitivity, coma HOA, and simulated keratometry were found to be the main factors that predicted improvement of both postoperative CDVA and UDVA compared to preoperative CDVA. Furthermore, mesopic contrast sensitivity, coma HOA, and high laser fluence were the common predictors of achieving both CDVA and UDVA supernormal vision 1 year after refined single-step TransPRK. [J Refract Surg. 2019;35(12):771-780.].