AIM:To observe the changes of tear film after laser assisted in situ keratomileusis(LASIK)with corneal flap created by femtosecond laser with preoperative artificial tears intervention. In the meantime, to analyze the main clinical characteristics of dry eye.

METHODS: The 434 myopic patients(859 eyes)who underwent femtosecond laser surgery from Jul.2014 to Jul.2015 were enrolled in the study after 6mo follow-up. The patients were divided into two groups according to whether they dropt artificial tears in preoperative. The patients of group one didn't drop artificial tears(408 eyes of 205 patients), group two dropt artificial tears in preoperative(451 eyes of 229 patients). To record and analyze the consequence of the dry eye symptom score, tear break-up time(BUT), Schirmer Ⅰ test, corneal fluorescein staining's changes and correlative factors respectively in preoperative, the first week in postoperative, and the first month, the third month and the sixth month after surgery.

RESULTS:Dry eye symptom score: there were significant differences(P<0.05)between the first week and the first month in postoperative, while no significance(P>0.05)in the third and the sixth month between 2 groups. There existed significant differences in that of the first week and the first month after surgery compared with the preoperative level, in spite of no such significant differences existed in that of the third and the sixth month compared with the preoperative level. BUT: there were significant differences(P<0.05)in the first week, the first month and the third month between 2 groups, while no such obvious differences(P>0.05)in the sixth month. There existed significant differences in that of the first week, the first month and the third month compared with the preoperative level, while no such significant difference in that of the sixth month compared with the preoperative level. Schirmer Ⅰ test: there existed obvious differences(P<0.05)in that of the first week and the first month in postoperative between 2 groups, while no such obvious differences(P>0.05)in the third and the sixth month. There existed significant differences in that of the first week and the first month compared with the preoperative level. While no such significant difference existed in that of the third and the sixth month compared with the preoperative level. Corneal fluorescein staining: There existed obvious differences(P<0.05)in the first week, the first month and the third month after surgery between 2 groups. While no such obvious differences(P>0.05)existed in the sixth month between 2 groups. There existed significant differences in that of the first week and the first month compared with the preoperative level. While no such significant difference existed in that of the third month and the sixth month compared with the preoperative level.

CONCLUSION:The function of tear film is decreased in early postoperative by LASIK. However, the patients' tear film with preoperative artificial tears intervention recover much faster than the patients who do not use the artificial tears.