AIM:To compare the difference in central corneal thickness(CCT) measurements after laser in situ keratomileusis(LASIK) using Pentacam system and A-scan ultrasound pachymetry.METHODS:Pentacam system and A-scan ultrasonic pachymeter were used to measure the corneal thickness on 267 myopic cases(267 eyes)undergoing LASIK 1 month,3 months and 6 months after the operation.Then the results were compared.RESULTS:The differences between the instruments were evaluated with paired t-test.The correlation between the measurements was evaluated using Pearson correlation coefficients.Of the 267 eyes,the CCT values of the two methods were positively related by linear correlation analysis(r=0.985,P<0.01),and the CCT of the two methods 1 month,3 months and 6 months after LASIK had no statistically significant difference(P>0.05).CONCLUSION:Pentacam system can measure the CCT easily,accurately and without any invasion.It is more fit for people after LASIK to monitor the corneal changes with time and for people to do more deep research.