title: Early changes in ocular surface and tear inflammatory mediators after small-incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis.
abstract: OBJECTIVE
  To characterize the early ocular-surface changes or tear inflammatory-mediators levels following small-incision lenticule extraction (ReLEx smile) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).
  
  
  METHODS
  Forty-seven myopic subjects were recruited for this prospective study. Fifteen underwent ReLEx smile and thirty-two underwent FS-LASIK. Corneal fluorescein (FL) staining, tear break-up time (TBUT), Schirmer I test (SIT), ocular surface disease index (OSDI) and central corneal sensitivity were evaluated in all participants. Tears were collected and analyzed for interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), nerve growth factor (NGF) and intercellular adhesion molecule-1 (ICAM-1) levels using multiplex magnetic beads. All measurements were preformed preoperatively and 1 day, 1 week, 1 month and 3 months postoperatively.
  
  
  RESULTS
  FL scores in ReLEx smile group were lower than those of FS-LASIK group 1 week postoperatively (P = 0.010). Compared to the FS-LASIK group, longer TBUT were observed in ReLEx smile group 1 month (P = 0.029) and 3 months (P = 0.045) postoperatively. No significant differences were found in tear secretion for the two groups (P>0.05). OSDI scores were higher in FS-LASIK group 1 month after surgery (P = 0.020). Higher central corneal sensitivity was observed in ReLEx smile group 1 week, 1 month and 3 months (P<0.05) postoperatively. Compared to FS-LASIK group, lower and faster recovery of IL-6 and NGF levels in tears was observed in ReLEx smile group postoperatively (P<0.05). Tears TNF-α and ICAM-1 concentrations were not significantly different between the two groups at any follow-up time (P>0.05). Moreover, IL-6 and NGF levels correlated with ocular surface changes after ReLEx smile or FS-LASIK.
  
  
  CONCLUSIONS
  In the early postoperative period, ReLEx smile results in milder ocular surface changes than FS-LASIK. Furthermore, the tear inflammatory mediators IL-6 and NGF may play a crucial role in the ocular surface healing process following ReLEx smile and FS-LASIK.
authors.affiliation: Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China; Henan Eye Hospital and Henan Eye Institute, People's Hospital of Zhengzhou University, Zhengzhou, Henan Province, China.
authors.forename: Shaohui
authors.initials: S
authors.lastname: Gao
authors.affiliation: Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China.
authors.forename: Saiqun
authors.initials: S
authors.lastname: Li
authors.affiliation: Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China.
authors.forename: Liangping
authors.initials: L
authors.lastname: Liu
authors.affiliation: Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ding
authors.affiliation: Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.affiliation: Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China; Hainan Eye Hospital, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, Hainan Province, China.
authors.forename: Xingwu
authors.initials: X
authors.lastname: Zhong
mesh_terms: D000328:Adult; D000869:Anterior Eye Segment / Q000473:pathology* / Q000601:surgery; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism*; D020731:Keratomileusis, Laser In Situ; D009216:Myopia / Q000378:metabolism / Q000601:surgery*; D011446:Prospective Studies; D013666:Tears / Q000378:metabolism*; D055815:Young Adult
chemical_list: C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6