目的研究准分子激光原位角膜磨镶术(laser insitu keratomileusis,LASIK)术后角膜后表面前凸和屈光力的变化及影响二者变化的相关因素。方法对接受LASIK手术并有术后6个月随访记录、近视屈光度(等效球镜)为(-6.50±2.75)D的52例患者(76眼),于术前及术后第1个月、第2个月和第6个月分别行Orbscan-Ⅱ裂隙光扫描角膜地形图检查,测量角膜后表面前凸值、角膜后表面屈光力,观察其变化。用多元逐级回归法分析术前角膜最薄点厚度,以及眼内压、切削量与术后角膜后表面前凸的相关性。结果术后第1个月角膜后表面前凸值为(38.81±17.87)μm,术后第2个月为(35.61±13.60)μm,术后第6个月为(36.45±14.34)μm;3.0 mm直径角膜后表面屈光力均值术后第1个月为(-6.85±0.23)D,术后第2个月为(-6.83±0.28)D,术后第6个月为(-6.81±0.25)D;5.0 mm直径角膜后表面屈光力均值术后第1个月为(-6.34±0.24)D,术后第2个月为(-6.38±0.21)D,术后第6个月为(-6.39±0.25)D,上述观察值与术前比较差异有显著性(P<0.01),但术后第1个月同术后第2个月、第6个月比较差异无显著性。角膜后表面前凸值与角膜后表面屈光力线性相关(r=0.6,P<0.01)。多元逐级回归分析与术后角膜后表面前凸的变化有关系的变量为切削量(非标准系数B=0.405,P<0.01),角膜最薄点厚度(非标准系数B=-0.109,P<0.01),术前眼内压未进入最后回归方程。结论LASIK术后角膜后表面形态有显著性改变,角膜后表面呈锥形前凸,随术后时间延长角膜后表面形态趋于稳定;角膜厚度越薄、切削量越大则术后的角膜前凸值就越大。 Objective To study the changes of corneal posterior surface lordosis and refractive power and the related factors that affect the changes of both after laser in situ keratomileusis (LASIK). Methods Fifty-two patients (76 eyes) with myopic refraction (equivalent spherical scope) of (-6.50 ± 2.75) D undergoing LASIK and with a follow-up of 6 months postoperatively were enrolled in the study. Preoperative and postoperative first month At the second month and the sixth month, Orbscan-Ⅱ slit light scanning was performed to examine the corneal topography. The posterior corneal posterior kyphosis and corneal posterior refractive power were measured to observe the changes. The multivariate stepwise regression analysis was used to analyze the thickness of the thinnest point of the preoperative cornea and the correlation between the intraocular pressure and the amount of cutting and the postoperative corneal posterior surface lordosis. Results The value of corneal posterior kyphosis was (38.81 ± 17.87) μm in the first month after operation, (35.61 ± 13.60) μm in the second month and 36.45 ± 14.34 μm in the sixth month after operation (-6.85 ± 0.23) D in the first month after operation and (-6.83 ± 0.28) D in the second month after operation, and (-6.81 ± 0.25) in the sixth month after the operation. (P <0.05). The mean corneal surface power at the 5.0 mm diameter cornea was (-6.34 ± 0.24) D at 1 month after operation and (-6.38 ± 0.21) D at 2 months after operation, ± 0.25) D, there was a significant difference between the above observation and preoperative (P <0.01), but there was no significant difference between the first month after operation and the second month and the sixth month after operation. The posterior corneal posterior lordotic value was linearly correlated with corneal posterior refractive power (r = 0.6, P <0.01). The correlation between multivariate stepwise regression analysis and postoperative corneal posterior lordosis was the amount of cutting (non-standard coefficient B = 0.405, P <0.01) and the thinnest corneal thickness (non-standard coefficient B = -0.109, P <0.01), preoperative intraocular pressure did not enter the final regression equation. Conclusions The morphology of posterior corneal surface changes significantly after LASIK. The posterior corneal surface presents conical lordosis. The posterior corneal surface morphology tends to be stable with the prolonged postoperative time. The thinner the corneal thickness is, the larger the cutting amount is. The greater the convex value.