方法：选择要求LASEK手术的检测Q值为正的近视和散光患者158眼随机分为两组，接受Q值引导LASEK患者 86眼作为观察组， 接受常规LASEK的患者72眼为常规组。检测手术前后患者的裸眼视力(UCVA)、 最佳矫正视力(BCVA)、屈光度、眼压、角膜地形图、角膜曲率值K值(keratometry)、 非球面因子Q值(aspherical factor Q)、高阶像差(HOA)、超声角膜测厚、对比敏感度(CS)并且观察术后角膜上皮下混浊(haze)出现情况。术前所检测的各项指标两组差异无统计学意义。术后14d； 1，3，6，12mo随访。

结果：术后12mo时两组的UCVA及BCVA无统计学差异，但安全性指数观察组为1.10，常规组为1.07； 有效性指数观察组为1.06 ，常规组为0.99； 观察组总HOA为0.45±0.17μm，常规组为0.72±0.25μm，统计学差异显著(t=-8.193，P=0.000)； 观察组 Q值平均为0.41±0.17， 常规组为0.77±0.22 ，存在统计学差异(t=11.377，P=0.028)； 术后3mo观察组CS基本可以达到术前状态，而常规组术后 6mo恢复至术前水平。

结论：在治疗正性Q值患者的近视及散光方面Q值引导的LASEK较常规LASEK更好地保持了角膜的非球面性且安全有效，视觉质量更好。

METHODS: There were 158 eyes which were myopia and astigmatism with positive Q-factor taken in two groups randomly: 86 eyes accepted Q-factor guided LASEK as observation group and 72 eyes accepted routine LASEK as control group. The difference between the two groups about all data was similar. The uncorrected visual acuity(UCVA)and the best corrected visual acuity(BCVA)as well as diopter, ocular tension, corneal topography, Keratometry value K, aspherical factor Q, Higher-order aberrations(HOA), corneal thickness by ultrasound and, contrast sensitivity(CS), Haze were examined and compared before and after surgery. All the cased were followed up for 14d, 1, 3, 6, 12mo. And there were no statistical difference among the data before surgery.

RESULTS: After 12mo there were no statistical difference between the two groups about UCVA and BCVA. But the safety index of observation group was 1.10, that of control group was 1.07. The validity index of observation group was 1.06, that of control group was 0.99. The HOA of observation group was 0.45±0.17μm, and that of control group was 0.72±0.25μm, there was statistically significant difference(t=-8.193,P=0.000). Q factor of observation group was 0.41±0.17, that of control group was 0.77±0.22, there was significant difference(t=11.377,P = 0.028). The contrast sensitivity of 3mo post surgery of patients in the observation group returned to the level of before surgery. But in the control group the contrast sensitivity of the patients did not returned until 6mo.

CONCLUSION: Q-factor guided LASEK for myopia and astigmatism with positive Q-factor is stable, safe and effective. The operation allow for reducing the high order aberrations, maintaining the most asphericity of cornea, saving more in corneal tissue, which cause faster recovery of contrast sensitivity, less haze and better visual quality.