title: Correlation between the matrix metalloproteinase-9 activity and chondroitin sulfate concentrations in tear fluid after laser in situ keratomileusis.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the correlation between matrix metalloproteinase-9 (MMP-9) and chondroitin sulfate (CS) concentrations in human tear fluid following laser in situ keratomileusis (LASIK).
  
  
  METHODS
  Twelve eyes from six patients who had no ocular complaints except for refractive errors, and who had undergone LASIK, were enrolled in this study. We measured the concentrations of chondroitin 4 sulfate (C4S), chondroitin 6 sulfate (C6S), and MMP-9 activity with an enzyme-linked immunosorbent assay and an enzyme immunocapture activity assay preoperatively and postoperatively on days 1 and 4, week 1, and at 1 and 3 months.
  
  
  RESULTS
  Although the preoperative MMP-9 activity and the C4S concentration were highly correlated (r = 0.900; P < 0.001), they were not postoperatively correlated at month 1. Although the preoperative MMP-9 activity and the C6S concentration were highly correlated (r = 0.885; P < 0.001), they were not postoperatively correlated at either week 1 or months 1 and 3.
  
  
  CONCLUSIONS
  The correlation appeared to be collapsed by LASIK, and it did not recover to the preoperative score at 3 months post-surgery. Our study indicates that the corneal wound healing was not terminated at 3 months following LASIK.
authors.affiliation: Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mutoh
authors.forename: Masaya
authors.initials: M
authors.lastname: Nishio
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Arai