Abstract:

Objective To analyze the influence of different corneal refractive surgical methods on non-invasive tear function indicators. Design Retrospective comparative case series. Participants 42 cases (42 eyes) who underwent corneal refractive surgery and followed-up for at least 6 months. There were 20 patients (20 eyes) in LASIK group and 22 patients (22 eyes) in SBK group. Methods Non-invasive first tear film break-up time (NIBUTf),  non-invasive average tear film break-up time (NIBUTa) and lower tear meniscus height (LTMH) were assessed pre- and post-operative 10 days, 1 month,  3 months,  6 months using oculus keratograph. The right eye data were analyzed for comparison between the two groups. Main Outcome Measures NIBUTf, NIBUTa and LTMH. Results There was no significant difference of NIBUTf and LTMH between the two groups at all time points (all P>0.05). Compared to LASIK group,  the NIBUTa was elevated at postoperative 3 months in SBK group (P=0.02). For LASIK group,  compared to preoperative value,  postoperative NIBUTf decreased at 1 month and 3 months (all P<0.05),  but not at 10 days,  and 6 months (both P>0.05); both NIBUTa and LTMH value reduced at postoperative time points,  but the differences were not statistically significant (all P>0.05). For SBK group,  compared to preoperative value,  NIBUTf decreased at postoperative 10 days,  1 month,  3 months  (all P<0.05),  but recovered at 6 months after surgery （P=0.14); NIBUTa decreased at postoperative 10 days (P=0.04),  but not at 1 month and 3 months(both P>0.05). There was no statistical difference of LTMH at every postoperative time point compared to preoperative value ( all P>0.05). Conclusion Compared to preoperative value,  NIBUTf and NIBUTa temporally decreased after LASIK and SBK,  recovered to preoperative level at postoperative 6 months. Compared to LASIK,  the NIBUTa was higher at postoperative 3 months in SBK group. The tear film function restored faster in SBK than LASIK group. （Ophthalmol CHN,  2018, 27：117-121）

Key words: SBK, LASIK, keratograph； non-invasive tear film break-up time