Comparative Study of Dry Eye after FS-LASIK and Off-Flap LASEK

Objective: To compare dry eye characteristics in eyes after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) or off-flap laser epithelial keratomileusis (LASEK). Methods: Thirty eyes of 30 patients with myopia who had FS-LASIK (FS-LASIK group) and 30 eyes of 30 patients with myopia who had off-flap LASEK (LASEK group) at the Refractive Surgery Center of the Ningbo Eye Hospital from August 2016 to February 2017 were prospectively enrolled in this clinical study. The Ocular Surface Disease Index (OSDI) questionnaire, Schirmer Ⅰ test (SⅠT), tear breakup time (BUT), and corneal fluorescein staining were evaluated preoperatively and 3, 6, and 12 months postoperatively. Data from the two groups were analyzed with a two-way repeated measures ANOVA. Results: There were no statistically significant differences between the two groups for the OSDI questionnaire score, SⅠT, and corneal fluorescein staining at all time-points and for the preoperative and 3 and 6 months postoperative BUT (P>0.05). The BUT of the FS-LASIK group was higher than that for the LASEK group after 12 months (t=2.81, P=0.01). Compared with the preoperative evaluation, corneal staining increased in the FS-LASIK group after 3 months (t=3.48, P=0.008), but there were no statistically significant differences between 6 and 12 months postoperative and the preoperative. There were no statistically significant differences between postoperative and preoperative for the corneal fluorescein staining in the LASEK group (P>0.05). There were no statistically significant differences between postoperative and preoperative for the OSDI questionnaire score and Schirmer Ⅰ in both groups (P>0.05), and there were no statistically significant differences between 3 and 6 months postoperative and the preoperative for the BUT in both groups (P>0.05). Compared with the preoperative evaluation, the BUT increased in the FS-LASIK and LASEK groups after 12 months (t=3.14, P=0.01; t=2.43, P=0.04). Conclusions: Dry eye is slight after FS-LASIK and off-flap LASEK surgeries, and both techniques have a similar effect on dry eye. Key words: femtosecond laser; laser in situ keratomileusis; laser epithelial keratomileusis; dry eye