Changes in corneal asphericity and corneal aberration after laser coneal refractive surgery

Objective To investigate changes of corneal asphericity and ocular aberration and its related factors after Laser Keratectomy.Methods Retrospectively study clinical data of 94 eyes from 49 patients before and after Laser Keratectomy.Changes in corneal asphericity and ocular aberration after LASIK and LASEK were compared.Results 1)corneal asphericity(Q value)was(-0.32±0.11)and the corneal aberration was(0.51±0.19)μM preopreratively.2)The clinical data showed that spherical aberration was increased 4.37 folds after myopic correction(P0.01).The change of spherical aberration was correlated to the change of spherical equivalent(SE)(r=0.520,P0.01)and the change of the Q-value(r=0.792,P0.01).3)After excimer laser procedures,all corneas generally changed from a prolate(Q0)to an oblate(Q0)optical contour and it was correlated to the change of spherical equivalent(SE)(r=0.578,P0.01).4)The degree of corneal asphericity and ocular aberration and the change of them after LASEK was smaller than those after LASIK.Conclusion The exicimer ablation,the biomechanical and wound-healing responses of the cornea induced the corneal surface change.Changes in corneal asphericity result in the in increase of spherical aberration.