LASIK术前术后角膜Q值变化的临床研究

目的探讨准分子激光角膜屈光手术矫正近视术前术后角膜Q值的变化。方法428只近视眼按屈光度分为中／低度近视组（n=344）和高度近视组（n=84）。检查记录术前及术后6个月患者视力、散瞳检影及主觉插片确定屈光度和最佳矫正视力、眼压、角膜厚度，角膜地形图测量并记录手术前后角膜Q值并进行统计学分析。结果所有术眼手术前后角膜Q值比较差异有统计学意义（P〈0．01）。术前角膜Q值两组间差异无统计学意义（P〉0．05），但术后角膜Q值两组间差异有统计学意义（P〈0．01）。高度近视组手术前后角膜Q值变化的绝对值大于中／低度近视组。术后角膜Q值变化与术前屈光度的大小有统计学意义（P〈0．01），与年龄、性别等无明显相关性。结论准分子激光角膜屈光手术后角膜Q值发生显著改变，由术前中央陡周边平坦（Q值〈0）的长椭圆非球面形变为中央平坦周边陡（Q值〉0）的扁椭圆非球面形，高度近视组手术后角膜Q值改变程度大于中／低近视组。Q值的变化量与角膜曲率变化量、角膜散光变化量有明显关系，影响术后视觉质量。

Research of the changes of Q - value of the cornea in myopic eyes undertaken excimer laser refractive surgery

Object To study the changes of corneal anterior surface profile in myopic eyes undertaken excimer laser refractive surgery. Methods A total of 428 myopic eyes were divided into lwo groups according to low/moderate myopia （ n = 344 ）and high myopia（ n = 84）. The average corneal Q values before and after laser refractive surgery were measured by Astra- max corneal topographer and were analyzed statistically. And analyzed the relationship between Q value with sex, age, refractive diopter,cornea curvature,cornea diameter and so on. Results The comeal Q values in all eyes showed a statistically signifi cant change after surgery （ P 〈 0. 01 ）. There were no statistical significance of corneal Q values between two groups before op- eration（ P 〉 0.05 ） , However, after operation, therc was a significant difference between groups. High myopia group had larger changes on corneal Q values than that in low / moderate myopia group. The changes of corneal Q values post - operalion had positive relationship with diopter corrected by surgery,and no positive relationship with age or sex. Conclusion The superficial profile of cornea in myopic eyes changes significantly after laser refractive surgery, and the remodel in high myopia group is larger than that in low/moderate group. The Q value was changed by LASIK appointed with the change of cornea curvature and cornea astigmatism. The change would influence the vision quality postoperation.