This prospective randomized comparative study was approved by the Institutional Review Board, Yonsei University College of Medicine, Seoul, South Korea (IRB No. 4-2016-0840). The study adhered to the tenets of the Declaration of Helsinki and followed good clinical practices. All patients provided informed consent after a detailed explanation of the possible risks and benefits of the study. The right eye of each patient was included in the study unless contraindicated, in which case the left eye was used. The patients were randomized to one of two groups (L-SMILE or C-SMILE) by means of permuted block-randomization with the Clinstat software (Available from: http://www-users.york.ac.uk/~mb55/soft/soft.htm). Thereafter, the patients were randomly allocated a laser energy level within their SMILE group by means of minimization with the Minim software (Available from: http://www.users.york.ac.uk/~mb55/guide/minim.htm) due to the small sample size (< 200).