ABSTRACT
@#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. <p>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 <i>t</i>-test or Mann-Whitney <i>U</i>. Pearson or Spearman correlations were used to evaluate the relationship between parameters.<p>RESULTS: The postoperative 1<sup>st</sup> A-time, Vin, 2<sup>nd</sup> A length, Vout, HC time and Radius demonstrate significant decreases comparing with preoperative values(<i>P</i>=0.00, <i>P</i>=0.00, <i>P</i>=0.00, <i>P</i>=0.00, <i>P</i>=0.00, <i>P</i>=0.00 respectively). The postoperative 2<sup>nd</sup> A-time, DA and PD significantly increases(<i>P</i>=0.00, <i>P</i>=0.00, <i>P</i>=0.00), however, the 1<sup>st</sup> A length had no significant difference after surgery. The CH and CRF were significantly lower after FS-LASIK(<i>P</i>=0.00, <i>P</i>=0.00). A statistically significant correlation coefficient was found between preoperative central corneal thickness(CCT)with postoperative-preoperative changes of 1<sup>st</sup> A-time, 2<sup>nd</sup> A-time, DA and Radius respectively(<i>P</i>=0.01, <i>P</i>=0.04, <i>P</i>=0.03, <i>P</i>=0.01). <p>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.