title: Comparison of corneal sensitivity, tear function and corneal staining following laser in situ keratomileusis with two femtosecond laser platforms.
abstract: OBJECTIVE
  To evaluate longitudinal changes in corneal sensitivity, tear function, and corneal staining in patients who underwent laser in situ keratomileusis (LASIK) using two different femtosecond lasers.
  
  
  METHODS
  In a prospective, randomized clinical trial, contralateral eyes of 45 patients underwent flap creation by either VisuMax or IntraLase™ femtosecond laser. Corneal sensitivity, tear break up time (TBUT), Schirmer's test, and corneal fluorescein staining were assessed preoperatively and at 1 week, 1 month, and 3 months postoperatively.
  
  
  RESULTS
  There were no statistical differences in any clinical outcome measure between the two femtosecond lasers (P > 0.05), although there was a trend towards slightly lower reductions for corneal sensitivity and TBUT in VisuMax-operated eyes. Overall, corneal sensitivity was significantly reduced at 1 week (P < 0.05), 1 month (P < 0 .001), and 3 months (P < 0.001) postoperatively. A significantly greater reduction of corneal sensitivity was noted in eyes with a myopic spherical equivalent of -6.00 diopters (D) to -11.25 D as compared with eyes that had a relatively lower level of myopia of less than -6.00 D (P < 0.001). TBUT and Schirmer's test values were significantly diminished at 1 week postoperatively (P < 0.04). Overall, corneal staining was significantly increased at 1 week postoperatively (P < 0.001). The level of myopia did not significantly affect postoperative changes in TBUT, Schirmer's test values, or corneal staining (P > 0.05).
  
  
  CONCLUSIONS
  This study showed that changes in corneal sensitivity, tear function, and corneal staining were statistically similar in LASIK using VisuMax and IntraLase femtosecond lasers for flap creation. However, the trend towards faster recovery of corneal sensitivity and TBUT observed in VisuMax-operated eyes may be attributable to improved technical specifications.
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Andrea
authors.initials: A
authors.lastname: Petznick
authors.forename: Annabel
authors.initials: A
authors.lastname: Chew
authors.forename: Reece C
authors.initials: RC
authors.lastname: Hall
authors.forename: Cordelia Ml
authors.initials: CM
authors.lastname: Chan
authors.forename: Mohamad
authors.initials: M
authors.lastname: Rosman
authors.forename: Donald
authors.initials: D
authors.lastname: Tan
authors.forename: Louis
authors.initials: L
authors.lastname: Tong
authors.forename: Jodhbir S
authors.initials: JS
authors.lastname: Mehta
keywords: Schirmer’s; corneal sensitivity; corneal staining; femtosecond laser; tear film break-up time