Q值优化非球面切削矫正高度近视的远期高阶像差观察

Long-term higher-order aberration study on Q-value optimized aspheric ablation in high myopia

目的观察Q值优化的非球面切削准分子激光手术矫正高度近视的远期Q值和高阶像差变化。方法回顾性分析2007年在上海交通大学附属第六人民医院眼科行Q值引导的个体化切削（F—CAT）准分子激光手术的高度近视患者35例（70眼），其中行准分子激光原位角膜磨镶术（LASIK117例（34眼），准分子激光上皮瓣下角膜磨镶术（LASEK）18例（36眼），观察并用配对≠检验比较两种手术方式术前、术后远期角膜Q值和高阶像差的变化，采用独立样本t检验比较两组间各项指标的差异，采用Pearson相关和线性回归分析术后高阶像差的相关影响因素。结果术后3年，所有患者裸眼视力〉10．8，LASIK组和LASEK组安全性指数均〉1，有效性指数均接近1。两组Q值与术前相比，均从负值变为正值。术后总高阶像差均比术前增加，差异有统计学意义（t=-3．90、-6．75，P〈0．01）。术后LASIK组和LASEK组三阶像差均方根（RMS）值（t=-3．50、-5．22）、四阶像差RMS值（t=-6．79、-10．14）、垂直彗差RMS值（t=5．73、-5．50）、球差RMS值（t=-8．57、-13．79）均比术前增加（P〈0．01），两组间垂直彗差，球差差异均无统计学意义；水平彗差与术前相比差异无统计学意义。术后总高阶像差RMS值（R^2=372，F=16．96，P〈0．01）和术后球差RMS值（R^2=0．224，F=10．93，P〈0．01）与术前等效球镜度、手术光学区大小相关。术后垂直彗差与术前等效球镜度、手术目标Q值相关（R^2=0．224，F=10．93，P〈0．01）。结论Q值引导LASIK和LASEK矫正高度近视手术远期安全、有效。IASIK和LASEK术后Q值均由负值变为正值，远期高阶像差和球差增加。垂直彗差的增加可能与手术瓣蒂位置有关。术后高阶像差与患者术前屈光度、手术方式及光学区相关。

Objective To observe the long-term changes in Q-value and higher-order aberrations after Q-value optimized ablation in high myopia. Methods Seventy eyes of 35 high myopic patients treated with Q-value optimized ablation were retrospectively studied, including 34 eyes of 17 patients treated with laser in situ keratomileusis （LASIK） and 36 eyes of 18 patients treated with laser epithelial keratomileusis （LASEK）. Preoperative and long-term postoperative Q-value and higher-order aberrations were compared using a paired t test and an independent samples t test and the differences and influential factors were analyzed using Pearson correlation and linear regression. Results All patients had visual acuity over 0.8. Both Q-value optimized LASIK and LASEK had greater safety than one and validity close to one. Compared to preoperative Q-value, postoperative Q-value in both the LASIK and LASEK groups had changed from negative to positive. The differences in higher-order aberrations between preoperative and postoperative data were statistically significant in both groups （t=-3.90, -6.75, P〈0.01）. Root mean square （RMS） value of third order （t=-3.50, -5.22）, RMS value of fourth order （t=-6.79, -10.14）, RMS value of spherical aberration （t=-8.57, -13.79） and RMS value of vertical coma （t=5.73, -5.50） in both groups showed statistically significant increases during the 3 years after surgery （P〈0.01）. The changes in RMS value of vertical coma and RMS value of spherical aberration were not statistically different between the two groups. The horizontal coma had no significant change postoperatively. Postoperative higher-order aberrations （R^2=0.372, F=16.96, P〈0.01） and spherical aberration （R^2=0.22g, F=10.93, P〈0.01） were correlated to preoperative spherical equivalent and optic zone. Postoperative vertical coma was correlated to preoperative spherical equivalent and target Q-value （R^2=0.224, F=10.93, P〈0.01）. Conclusion In high myopia, Q-value optimized ablation had good safety, efficacy and good predictability. Over 3 years, higher-order aberrations and spherical aberration increased while vertical coma decreased with no difference between two surgeries. Increase of the vertical coma may be relevant to the direction of flap hinge. Higher-order aberrations after surgery were mainly correlated to preoperative spherical equivalent and optic zone size.