The Clinical Study Of Early Changes In Tear Film And Corneal Topography After LASIK

Objective: To investigate the early changes and the relationship between tear film and corneal topography after laser in situ keratomileusis (LASIK), so as to find out the related factors of dry eye after LASIK.Methods: A prospective study of 120 eyes (62 participants) that underwent LASIK for myopia at the First Affiliated Hospital of Guangxi Medical University, between April 2010 and October 2010. Participants were evaluated before and after (1 week, 1, 3, and 6 months) surgery for dry eye symptoms, tear film stability (fluorescein staining, tear break-up time), Schirmer I test, corneal topography (Humphrey ATLAS Corneal Topography Systems).Results: Dry eye symptoms were severe and fluorescein staining scores increased at l week, l month, 3months postoperatively (P<0.01), but recover at 6 months. Lower tear volume after (1 week, 1 and 3 months) surgery (P<0.01), but regression was found at 6 months after surgery (P=0.704>0.05). Lower tear film stability after (1week, 1, 3and 6months) surgery. The irregular conformation of cornea was severe after LASIK, Corneal Irregularity Measurement and Shape Factor increase after (1week, 1, 3and 6months) LASIK(P<0.01).Comparison are made for BUT and CIM, BUT and SF, SIt and CIM. There are power-law relation between BUT and CIM (r=0.393), linear relation between BUT and SF (r=0.436), cubic relation between ST and CIM (r=0.320).Conclusions: Dry eye symptoms were more severe after LASIK. Tear volume decreased at l week, l month, 3 months postoperatively and rehabilitate until 6months. Tear film stability was destroyed after LASIK. The irregular conformation of cornea was severe and the corneal surface changed postoperatively. The destroyed of tear film stability postoperatively associate with the changes of ocular surface.