title: Transforming growth factor-β1 level in tears and corneal haze formation following flap-on or flap-off epi-LASIK.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Ophthalmology, Guangzhou General Hospital of Guangzhou Command, Guangzhou, China. jingch518@aliyun.com
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Suning
authors.initials: S
authors.lastname: Han
authors.forename: Yuping
authors.initials: Y
authors.lastname: Zou
authors.forename: Xiulan
authors.initials: X
authors.lastname: Zou
mesh_terms: D000328:Adult; D003315:Cornea / Q000601:surgery; D019573:Epithelium, Corneal / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D011184:Postoperative Period; D013524:Surgical Flaps; D013666:Tears / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D055815:Young Adult
chemical_list: D053773:Transforming Growth Factor beta1