Abstract: Objective To observe the influence of flap-on or flap-off Epipolis laser in situ keratomileusis (epi-LASIK) on the
release of transforming growth factor-β1 (TGF-β1) in tear fluid and corneal haze formation. Methods Thirty patients (60 eyes)
with myopia underwent epi-LASIK surgery with epithelial flap repositioning (flap-on) in the right eyes and epithelial flap
removal (flap-off) in the left eyes. The level of TGF-β1 in tears was measured preoperatively and on days 1, 3, and 7
postoperatively. Corneal haze was graded at 1, 3 and 6 months after surgery. Results The mean preoperative spherical
equivalent refraction was -4.98±2.28 D (-2.50 to -7.25 D) in flap-on group and -5.20±4.02 D (-1.75 to -7.00 D) in flap-off group,
showing no significant difference between the two groups (P=0.80). TGF-β1 levels in the tear fluid were similar in the two
groups preoperatively (P=0.11) and at 1, 3, and 7 days postoperatively (P=0.55, 0.45, 0.19, respectively). TGF-β1 levels in tears
gradually decreased after the first postoperative day in both groups, but were still higher than the preoperative value till the
7th postoperative day. Corneal haze scores in the two groups were similar at 1 month (P=0.98), 3 months (P=0.52), and 6 months
(P=0.72) after the operation. Conclusion Flap-on and flap-off epi-LASIK surgeries do not differ significantly in postoperative
TGF-β1 levels in the tear fluid or in the postoperative haze scores. TGF-β1 may play a role in corneal wound healing.