AIM:To discuss the related factors that affected the stability of posterior corneal surface after laser in situ keratomileusis(LASIK).

METHODS: About 64 patients(64 eyes)were enrolled. The correlation among the changes in posterior corneal surface 6 month after LASIK, surgery method, corneal flap thickness(FT), ablation thickness(AT), postoperative residual corneal stroma thickness(RCST), preoperative thinnest corneal thickness(CT), flap thickness/preoperative thinnest corneal thickness(FT/CT), ablation thickness/preoperative thinnest corneal thickness(AT/CT), postoperative residual corneal stroma thickness/preoperative thinnest corneal thickness(RCST/CT), anterior and posterior preoperative corneal height, the difference of the forward shift in posterior corneal surface(diff value)of preoperative and preoperative intraocular pressure were analyzed.

RESULTS: The changes of diff value between preoperative and postoperative were related with diopter(r=0.419, P=0.014), AT(r=0.394, P=0.023), AT/CT(r=0.501, P=0.004), Diff value of preoperative(r=0.501, P=0.004), RCST(r=-0.385, P=0.033)and RCST/CT(r=-0.401, P=0.025). The changes of height value from posterior corneal surface between preoperative and postoperative were related with diopter(r=0.520, P=0.002), AT(r=0.504, P=0.003), AT/CT(r=0.442, P=0.013), Diff value of preoperative(r=0.624, P=0.000)and RCST/CT(r=-0.394, P=0.028).

CONCLUSION: AT, RCST, AT/CT, RCST/CT and diff value of preoperative should be the key index that predicted the stability of posterior corneal surface after LASIK,the further research will give the range of safety value.