Biomedical Research

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Comparison of postoperative long-term stabilities of tear film and cornea after femtosecond small incision lenticule extraction and femtosecond laser in situ keratomileusis

Objective: To compare the effects of femtosecond Small Incision Lenticule Extraction (SMILE) and femtosecond laser in situ keratomileusis (LASIK) on postoperative long-term stabilities of tear film and cornea.

Methods: 115 patients with corneal refractive surgery in our hospital from August 2014 to August 2016 were selected as the subjects, and were divided into the SMILE group and FS-LASIK group according to the date of admission. The changes in tear film Breakup Time (BUT), Schirmer I test (SIt) value and posterior corneal surface height were measured and compared before and after operation between the two groups.

Results: Before operation, there were no significant differences in BUT value and SIt value between the two groups (P>0.05); At 1 and 3 months after operation, the BUT value and SIt value of the SMILE group were significantly higher than those of the FS-LASIK group (P<0.05); At 6 and 12 months after operation, there were no significant differences in BUT value and SIt value between the two groups (P>0.05). At 1 months after operation, the BUT value and SIt value of the SMILE group were significantly lower than those before operation (P<0.05); There were no significant differences between the BUT value and SIt value of the SMILE group at 3, 6 and 12 months after operation and those before operation (P>0.05). At 1 and 3 months after operation, the BUT value and SIt value of the FS-LASIK group were significantly lower than those before operation (P<0.05); There were no significant differences between the BUT value and SIt value of the FS-LASIK group at 6 and 12 months after operation and those before operation (P>0.05).

Conclusion: There were no significant differences in the posterior corneal surface height between the femtosecond SMILE and femtosecond LASIK, but the femtosecond SMILE had obvious advantage in tear film stability, especially in recovery course at early stage after operation.

Author(s): Dafu Chen, Kunying Yu, Xu Zhang, Hongfei Liao