AIM: To investigate the changes of corneal biomechanical properties before and after femtosecond laser assisted LASIK(FS-LASIK)using Corneal Visualisation Scheimpflug Technology(Corvis ST)and Ocular Response Analyzer(ORA), and the correlation with other myopic parameters.

METHODS:Sixty three patients(63 eyes)who had myopic femtosecond laser assisted LASIK(FS-LASIK)were enrolled in the study. The right eye of each patient was analyzed in this study. The corneal biomechanical parameters pre-operative and 1mo post-operative was measured with the Corvis ST(Oculus, Wetzlar, Germany)and ORA(Reichert, Buffalo, New York, USA). Comparison of the biomechanical property values before and after surgery was peformed using Paired t-test or Mann-Whitney U. Pearson or Spearman correlations were used to evaluate the relationship between parameters.

RESULTS: The postoperative 1^st A-time, Vin, 2^nd A length, Vout, HC time and Radius demonstrate significant decreases comparing with preoperative values(P=0.00, P=0.00, P=0.00, P=0.00, P=0.00, P=0.00 respectively). The postoperative 2^nd A-time, DA and PD significantly increases(P=0.00, P=0.00, P=0.00), however, the 1^st A length had no significant difference after surgery. The CH and CRF were significantly lower after FS-LASIK(P=0.00, P=0.00). A statistically significant correlation coefficient was found between preoperative central corneal thickness(CCT)with postoperative-preoperative changes of 1^st A-time, 2^nd A-time, DA and Radius respectively(P=0.01, P=0.04, P=0.03, P=0.01).

CONCLUSION:There were significantly changes of corneal biomechanical properties after FS-LASIK surgery. The changes of corneal biomechanical properties after FS-LASIK can be reflected by some parameters of Corvis ST and ORA. The mainly influence of corneal biomechanical alteration was possibly correlation with corneal thickness.