Objective To evaluate silicone hydrogel contact lenses applied immediately after laser in situ keratomileusis (LASIK).Methods It was a prospective self-controlled study,and was based on 25 myopic patients (50 consecutive eyes) who underwent bilateral LASIK.The patients were randomly fitted with a PureVision lens in one eye and nothing in the fellow eye immediately after LASIK.The contact lenses were removed the next day.The fluorescein staining score,tear break-up time,Schirmer l test and subjective score were assessed preoperatively and 1 day, 1 week,1 month and 3 months postoperatively.Postoperative complications related to the corneal flap were also assessed.All values were compared between the treated eyes and the control eyes at the above time points.In addition,the parameters of the corresponding eyes were also estimated before and after surgery (1 day,1 week, 1 month and 3 months).The ANOVA for repeat measurements or Kruskal-Wallis ranks test were used for statistical analysis,For the differences between paired eyes,a paired-samples t test or Wilcoxon matched-samples rank sum test were used. A chi-square test was used for the incidence of complications related to the corneal flap.Results The fluorescein staining score of the treated eyes showed improvement by 1 day (Z=-3.00,P＜0.01) and 1 week (Z=-2.32,P＜0.05)postoperatively in contrast with the control,but a significant aggravation in both eyes was found at 1 day (Z=4.80,P＜0.0125; Z=6.20,P＜0.0125) and 1 week (Z=3.25,P＜0.0125; Z=4.26,P＜0.0125)after LASIK compared to preoperative conditions.Compared to the control eye,tear break-up time of the treated eye showed an increase 1 day (t=2.40,P＜0.05) and 1 week (t=2.09,P＜0.05) after LASIK,but obvious decreases were observed on any visit after the operation for both eyes (F=3.12,P＜0.05; F=4.05,P＜0.05).The Schirmer I test showed no statistically significant differences between the treated and control eyes postoperatively. Nevertheless, both eyes showed the same reductions (F=4.64,P＜0.05; F=5.77,P＜0.05) when compared to preoperative levels and at 1 week, 1 month,and 3 months postoperatively.Subjective scores of the treated eye were lower by 1 day (Z=2.15,P＜0.05) postoperatively compared to the control eye but there was a significant severity (Z=2.92,2.66,2.28,2.46,P＜0.0125:Z=4.00,3.39,2.88,3.07,P＜0.0125) at any visit after LASIK for either eye.No complications related to corneal flap were found postoperatively for any patient. Conclusion Silicone hydrogel contact lenses applied immediately after LASIK can reduce injury to the superficial cornea, increase stability of tear film and effectively alleviate patient discomfort during the early postoperative period.However, it cannot affect the time span during which dynamic ocular surface tear film changes and symptoms occur in response to LASIK.