LASIK后角膜高阶像差改变分析

Analysis of the change of corneal higher-order aberrations after laser in situ keratomileusis

目的探讨近视IASIK术后角膜高阶像差的变化情况。方法回顾性分析近视LASIK手术患者75例145只眼，比较患者术前术后角膜非球面系数（Q值）、总体高阶像差均方根值（RMSh）、3-7阶像差均方根值（RMS3-RMS7）、球差、慧差、三叶草像差等数值，用多元线性回归分析筛选引起术后角膜高阶像差改变的因素。结果术前角膜高阶像差与年龄无相关关系；术后各观察值的大小主要受术前相应各数值的大小、预矫屈光度数、切削区大小等因素的影响，术前值越大、预矫屈光度越大以及切削区越小，术后角膜高阶像差值越大；术后Q值、RMSh以及球差的增加量主要受预矫屈光度数和切削区大小的影响；慧差以及三叶草像差的增加与切削区大小无关。使用较小切削区（5．25mm）时的单位屈光度矫正引起的高阶像差增加值以及角膜前表面非球面系数改变值高于使用较大切削区时，差异有统计学意义。结论LASIK术后角膜高阶像差增大，预矫屈光度数高和切削区小是引起术后角膜高阶像差增加较大的主要原因。

Objective To investigate the change of corneal higher-order aberrations （HOA） after laser in situ keratomileusis. Methods Retrospectively analyzed 145 eyes from 75 patients after myopic LASIK and compared the pre- and post-operative values of the asphericity （Q）,RMSh,RMS3-RMS7,spherical aberration, coma and trefoil. To screen the influence factors to the increment of every component of corneal HOA by using the linear multifactor regression.Results The corneal HOA has no correlation with age. The post-operative values of every component of corneal HOA are mainly affected by the pre-operativc value, attempted spherical equivalent （SE）, and oblation zone （OZ）. The higher the pre-operative value, the higher the attempted SE and the smaller the OZ, the higher the post-operative value. The increments of Q value, RMSh and the spherical aberration depend on the attempted SE and OZ. The increments of coma and trefoil have no correlation with the oblation zone. Compared with the larger oblation zone （〉6.0mm）, every diopter correction with the smaller OZ will result in a significant higher post-operative corneal HOA and more positive post-operative Q value.Conclusion The attempted SE and the OZ are the main reasons responsible for the increase of the corneal HOA after LASIK.