AIM: To compare the changes of dry eye symptoms and signs after femtosecond-assisted laser in situ keratomileusis(LASIK)and conventional LASIK by Keratograph 5M.

METHODS: Sixty patients(120 eyes)who underwent corneal refractive surgery from June 2017 to November 2017 were enrolled. Thirty patients(60 eyes)underwent femtosecond-assisted laser LASIK and 30 patients(60 eyes)underwent conventional LASIK. All patients took examinations of Keratograph 5M dry eye related examinations,routine ophthalmological examinations and ocular surface disease index(OSDI)questionnaire before and 1wk, 1mo, 3mo and 6mo after surgery.

RESULTS: One week after operation, the OSDI scores of two groups were significantly higher than pre-operation(P<0.01), but 1mo after operation, the two groups recovered to the preoperative level(P>0.05). Noninvasive tear film break-up time(NI-BUT)in the conventional group was shorter 1wk, 1mo and 3mo after operation(P<0.01), while it was shorter in 1wk and 1mo after operation in femtosecond laser group(P<0.01). There was significant difference between conventional group and femtosecond laser group at 3mo after operation in NI-BUT(P<0.01). Tear meniscus hight(TMH)and the thickness of lipid layers of the two groups all decreased in 1wk and 1mo after operation(P<0.05).

CONCLUSION: Whether femtosecond-assisted or conventional LASIK will affect tear film stability and cause dry eye symptoms. The degree of influence decreases gradually with the time after operation, but femtosecond laser group can recover more quickly.