Clinical comparison of off-flap Epi-LASIK and on-flap Epi-LASIK for correcting myopia

Abstract

Objective To compare the clinical outcomes of eyes treated with off-flap epipolis laser in situ keratomileusis (Epi-LASIK) and contralateral eyes treated with on-flap Epi-LASIK for correcting myopia.Methods This prospective and randomized study enrolled 26 myopic patients who had undergone off-flap Epi-LASIK in one eye (off-flap group) and on-flap Epi-LASIK in the contralateral eye (on-flap group).Patients were followed up at 2 hours,1,3,5,and 12 days and 1,3 and 6 months after surgery.A paired samples t test,Wilcoxon signed ranks test or Pearson chi-square test were used to compare the two groups for uncorrected visual acuity (UCVA),spherical equivalent (SE),percentage of corneal epithelial healing,pain score,haze score and postoperative change in lines of best corrected visual acuity (BCVA).Results Compared to the on-flap group,outcomes for the off-flap group showed better UCVA at 5 days after surgery (t=-2.636,P=0.014),a higher percentage of corneal epithelial healing at 3 and 5 days after surgery (Z=-3.738,-3.589,P＜0.01),and lower scores for level of pain at 5 days after surgery (U=11.714,P=0.008).No significant between-group differences were found for SE and haze scores at 1,3 and 6 months after surgery,and the change in lines of BCVA at 3 months after surgery.Conclusion In comparison to on-flap Epi-LASIK, off-flap Epi-LASIK offers comparable refractive results, BCVA, and postoperative haze formation,but faster visual recovery and corneal epithelial healing. Key words: Keratectomy,subepithelial,laser-assisted; Myopia; Epithelium,corneal; Healing; Haze ; Off-flap