To compare the quantitative and qualitative optical outcomes between single-step transepithelial photorefractive keratectomy (TransPRK) and off-flap epipolis laser in situ keratomileusis (Epi-LASIK) in moderate to high myopia.we included patients with moderate to high myopia who were randomized to have TransPRK in one eye and Epi-LASIK in the other eye. All patients underwent comprehensive ophthalmological examinations, including uncorrected (UDVA) and corrected distance visual acuities (CDVA), manifest refraction, intraocular pressure, anterior and posterior segment examination, corneal topography measured by Scheimpflug scanning-slit topographer (Pentacam, Oculus Optikgerate GmbH), contrast sensitivity (CS) under photopic and mesopic conditions (CSV-1000E, Vector Vision Inc., Greenville, OH, USA) with correction by spectacles, ocular wavefront aberrometry (OPD-Scan II, Nidek Co. Ltd). At each follow-up, CS and aberration measures were repeated 3 times and the average value was analyzed. Optical parameters were repeated 1, 3, 6, and 12 months after surgery.Statistical analysis was performed using SPSS software (version 22.0, SPSS, Chicago, Inc.). Kolmogorov-Smirnov test was used to check the normal distribution of variables. Student t-test or Wilcoxon rank sum test was used based on the normality of data. A P value less than 0.05 was considered statistically significant.

Inclusion Criteria:

• age over 18 years
• corrected distance visual acuity (CDVA) in logarithm of minimal angle of resolution (LogMAR) of 0.10 or better
• refractive error stabilized for at least 1 year
• discontinued contact lens use for at least 2 weeks

Exclusion Criteria:

• presence of corneal scars
• keratoconus
• glaucoma
• retinal diseases
• a history of corneal or intraocular surgery

people accepted refractive surgery