tear secretion and tear film instability after laser in situ keratomileusis vs laser assisted subepithelial keratectomy

purpose: to evaluate and compare tear secretion and tear film instability following laser in situ keratomileusis (lasik) and laser assisted subepithelial keratectomy (lasek). methods: in a randomized clinical trial, 30 eyes of 15 patients underwent lasik and 30 eyes of 15 patients underwent lasek to correct myopia. tear secretion and tear film instability were tested preoperatively, 2 and 6 weeks, and 6 month postoperatively, using tbut (tear break-up time) and schirmer i and ii tests. results: six month after surgery, tbut, schirmer i, ii tests decreased significantly in lasik group compared with lasek group. there was no significant difference between lasik and lasek groups preoperatively. conclusion: the decrease in tear secretion was greater after lasik than lasek at 6 months' follow up. proper treatment of dry eye is required after lasik and lasek, particularly after lasik surgery.