title: Comparative analysis of two femtosecond LASIK platforms using iTRAQ quantitative proteomics.
abstract: OBJECTIVE
  New femtosecond laser platforms may reduce ocular surface interference and LASIK-associated dry eye. This study investigated tear protein profiles in subjects who underwent LASIK using two femtosecond lasers to assess differences in protein expression.
  
  
  METHODS
  This was a randomized interventional clinical trial involving 22 patients who underwent femtosecond laser refractive surgery with a contralateral paired eye design. Corneal flaps of 22 subjects were created by either Visumax or Intralase laser. Tear samples were collected preoperatively, and at 1 week and 3 months postoperatively using Schirmer's strips. Tear protein ratios were calculated relative to preoperative protein levels at baseline. The main outcome measures were the levels of a panel of dry eye protein markers analyzed using isobaric tagging for relative and absolute quantitation (iTRAQ) mass spectrometry.
  
  
  RESULTS
  A total of 824 unique proteins were quantifiable. Tear protein ratios were differentially regulated between the eyes treated with different lasers. The secretoglobulins Lipophilin A (1.80-fold) and Lipophilin C (1.77) were significantly upregulated (P < 0.05) at 1 week postoperatively in Visumax but not in Intralase-treated eyes. At 1 week, orosomucoid1 was upregulated (1.78) in Intralase but not Visumax-treated eyes. In the same eyes, lysozyme, cathepsin B, and lipo-oxygenase were downregulated at 0.44-, 0.64-, and 0.64-folds, respectively. Transglutaminase-2 was downregulated in both groups of eyes.
  
  
  CONCLUSIONS
  Different laser platforms induce distinct biological responses in the cornea and ocular surface, which manifests as different levels of tear proteins. This study has implications for surgical technology and modulation of wound healing responses. (ClinicalTrials.gov number, NCT01252654.).
authors.affiliation: Narayana Nethralaya, Bangalore, India.
authors.forename: Sharon
authors.initials: S
authors.lastname: D'Souza
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Andrea
authors.initials: A
authors.lastname: Petznick
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
authors.affiliation: Singapore National Eye Centre, Singapore.
authors.forename: Reece C
authors.initials: RC
authors.lastname: Hall
authors.affiliation: Singapore Eye Research Institute, Singapore Singapore National Eye Centre, Singapore.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Rosman
authors.affiliation: Singapore National Eye Centre, Singapore.
authors.forename: Cordelia
authors.initials: C
authors.lastname: Chan
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Siew Kwan
authors.initials: SK
authors.lastname: Koh
authors.affiliation: Singapore Eye Research Institute, Singapore Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore Signature Research Program (SRP) Neuroscience and Behavioural Disorder, DUKE-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Roger W
authors.initials: RW
authors.lastname: Beuerman
authors.affiliation: Singapore Eye Research Institute, Singapore Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore Signature Research Program (SRP) Neuroscience and Behavioural Disorder, DUKE-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Singapore Eye Research Institute, Singapore Singapore National Eye Centre, Singapore Office of Clinical, Academic, and Faculty Affairs, Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Jodhbir S
authors.initials: JS
authors.lastname: Mehta
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D005136:Eye Proteins / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D005786:Gene Expression Regulation; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation* / Q000379:methods; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000235:genetics / Q000378:metabolism / Q000601:surgery*; D040901:Proteomics / Q000379:methods*; D013666:Tears / Q000737:chemistry*; D055815:Young Adult
chemical_list: D005136:Eye Proteins; C042434:tear proteins
keywords: laser; randomized controlled trial; refractive surgery; tears