Dry eye after LASIK with a femtosecond laser or a mechanical microkeratome

PURPOSE: Dry eye is the most common complication after LASIK procedure and is associated with corneal denervation. We conducted the study to compare dry eye parameters and corneal sensitivity (CS) after laser in situ keratomileusis (LASIK) with a femtosecond laser (FS) or microkeratome (MK). METHODS: In this prospective, nonrandomized, comparative study, 87 consecutive patients with myopia were assigned to receive either LASIK surgery with an FS (n = 44) or MK-assisted LASIK surgery (n = 43). The groups were age and sex matched. Corneal sensitivity, Schirmer testing, tear breakup time (TBUT), conjunctival and corneal stainings, and a subjective questionnaire (Ocular Surface Disease Index [OSDI]) were evaluated preoperatively, at 1 week, and at 1, 3, and 6 months postoperatively. RESULTS: Preoperative spherical equivalent and sphere, calculated ablation depth, and suction time differed significantly between the two groups (p < 0.01, all comparisons). Postoperatively, CS decreased in both groups and gradually recovered. Schirmer test values were not significantly different throughout the postoperative time points between the groups. Laser in situ keratomileusis-induced corneal epitheliopathy was also increased after operation in both groups. However, there was no significant difference between the groups in corneal and conjunctival staining scores. The OSDI scores were increased postoperatively in both groups. After adjustment for the calculated ablation depth, TBUT was the only parameter that was statistically higher in the FS group than in the MK group (p = 0.03). CONCLUSIONS: Both FS- and MK-assisted LASIK reduced CS and TBUT and increased corneal staining and OSDI scores. However, TBUT was significantly higher in the FS group than in the MK group after operation.