AIM: To evaluate changes in tear function and corneal staining in patients who underwent laser in situ keratomileusis(LASIK)using two different femtosecond lasers.

METHODS:Forty eyes underwent FS200 and 40 eyes underwent VisuMax. The tear film break-up time(TBUT), Schirmer I test(SⅠt)and fluorescein staining were assessed preoperatively at 1wk; 1 and 3mo postoperatively. The analysis of variance(ANOVA)for repeat measurements or Kruskal—Wallis ranks test were used. For the differences between FS200 and VisuMax-operated eyes, a independent-samples t test or Wilcoxon matched-samples rank sum test were used.

RESULTS: There were no statistical differences in any clinical outcome measure between the two kinds of lasers(P<0.05), although there was a trend towards slightly reductions for TBUT in FS200-operated eyes. TBUT of the two groups eyes showed the same reductions(F=100.37, P<0.01; F=112.25, P<0.01)when compared preoperative levels to 1wk; 1 and 3mo postoperatively levels. Moreover, there were obvious decreases of the Schirmer Ⅰ test were observed on any visit after the operation for both groups(F=42.15, P<0.01; F=37.27, P<0.01). Furthermore, corneal staining was significantly increased at 1wk postoperatively(FS200 Z=4.88, P<0.01; VisuMax Z=4.28, P<0.01)after LASIK compared to preoperative conditions, and recovered to the level of preoperative at 1mo postoperatively.

CONCLUSION: This study shows that changes in TBUT,Schirmer I test and corneal staining are statistically similar in LASIK using FS200 and VisuMax femtosecond lasers for flap creation. However, the VisuMax-operated eyes of TBUT after LASIK have faster recovery than in FS200 eyes.