AIM: To investigate the effect of strabismus surgery on tear film and the incidence of dry eye.

METHODS: A total of 66 eyes of 58 patients admitted and underwent surgery in our hospital between September 2018 to September 2019 with concomitant strabismus were enrolled. The patients were divided into two groups based on surgical methods: Group 1 included 25 cases(33 eyes)who underwent a single horizontal rectus cut; Group 2 included 33 cases(33 eyes)who underwent both horizontal rectus cut in. The noninvasive tear film break-up time(NIBUT)was examined with sirius anterior analysis system at the time of 1d preoperatively and 3d, 1wk, 2wk and 3wk after operation. In addition, the tear film break-up time(BUT), Schirmer I test(SⅠt)and corneal fluorescein examination were tested. The patients were diagnosed with dry eye in both groups according to the consensus of clinical experts specialized in the diagnosis and treatment of dry eye.

RESULTS: There were no statistically significant differences when compared to SⅠt between the two groups before and after surgery(P>0.05). The BUT of group 1 was higher than group 2 at postoperative 3d, 1wk and 2wk(P<0.05), while there was no difference between the two groups at 3wk postoperative(P>0.05); BUT returned to baseline by 2wk after surgery in group 1 and by 3wk after surgery in group 2. There were no differences between the NIBUT measured by sirius anterior segment analysis system and the BUT measured by traditional method before and after operation(P>0.05). The lowest incidence of dry eye was found at postoperative 2wk and 3wk in group 1(24%, 18%). The lowest incidence of dry eye was found at postoperative 3wk in group 2(15%). Besides, the incidence of dry eye in group 2 was higher than that in group 1 at postoperative 2wk(52% vs 24%, P<0.05).

CONCLUSION: There was no obvious influence on the SⅠt after strabismus surgery; the surgical effect on tear film was mainly reflected in BUT. The fewer muscles operated, the lesser tear film was affected and the tear film was recovered faster. The incidence of dry eye decreased as time went by.