Does hinge position affect dry eye after laser in situ keratomileusis?

PURPOSE: To evaluate the effect of corneal flap hinge position on dry eye after laser in situ keratomileusis (LASIK).

METHODS: In a prospective double-masked randomized controlled clinical trial, 212 consecutive eyes of 106 myopic patients underwent LASIK; in each patient, one eye was randomly assigned to the superior hinge and the other eye to the nasal hinge procedure. The patients were examined pre-operatively and 1 week, 1 month, 3 months and 6 months after surgery for visual acuity, fluorescein tear film breakup time and Schirmer's baseline tear secretion test; a subjective evaluation of dry eye symptoms was accomplished by the Ocular Surface Disease Index (OSDI) questionnaire at the 1-month, 3-month and 6-month postoperative visits.

RESULTS: Tear film breakup time was not significantly different with the nasal or superior hinge flap technique at the preoperative, 1-week, 1-month, 3-month and 6-month visits (p > 0.05 for all comparisons between two groups). No significant difference between the two groups was found for the amount of Schirmer's baseline tear secretion test at pre- and postoperative visits (p > 0.05 for all comparisons between two groups). Subjective evaluation of symptoms also showed no significant difference at the 1-month, 3-month and 6-month postoperative visits.

CONCLUSIONS: The nasal and superior hinge flap methods do not affect signs and symptoms of dry eye after LASIK. We recommend that selecting the hinge position should be done according to the surgeon's preference and ease.