Effect of Hinge Position on Corneal Sensation and Dry Eye Parameters After Femtosecond Laser–assisted LASIK

PURPOSE: To evaluate the effect of superior- versus nasal-hinged flaps on corneal sensation and dry eye after femtosecond laser–assisted LASIK. METHODS: A total of 43 patients who had undergone bilateral femtosecond laser–assisted LASIK for myopia were evaluated in a prospective, nonrandomized, contralateral eye study to compare the difference between different hinges on corneal sensation and dry eye. Corneal esthesiometry, Schirmer basic tear secretion test (BST), tear break-up time (BUT), ocular surface stainings, and the Ocular Surface Disease Index (OSDI) questionnaire were used to evaluate corneal sensation and dry eye parameters preoperatively as well as at 1 week and 1, 3, and 6 months postoperatively. RESULTS: Corneal sensation decreased significantly in both groups 1 week after surgery ( P <.05 in the nasal hinge group; P <.01 in the superior hinge group) and gradually recovered over the first 3 months. No significant change was noted in BUT after surgery in either group ( P >.05). Significant increases were noted in BST values at 1 and 3 months ( P <.05) and 6 months ( P <.01) postoperatively in both groups. Corneal fluorescein staining increased significantly in both groups at 1 week ( P <.01) and returned to baseline by 6 months. Conjunctival Rose Bengal staining decreased significantly by 6 months in the superior hinge group only ( P <.05). The OSDI significantly increased 1 week after surgery ( P <.01) and did not completely return to baseline by 6 months postoperatively in either group ( P <.05). No significant differences were noted in any of the parameters between groups at any time point ( P >.05). CONCLUSIONS: Hinge position had no significant effect on corneal sensation or dry eye parameters. Aggressive dry eye regimens are needed for patients with preoperative dry eye.