近视眼患者角膜高阶像差分布及LASIK和波前像差引导的优化LASIK术后高阶像差变化的研究

Clinical study on higher order aberrations distribution of anterior corneal in myopia and comparison of higher order aberrations changes after LASIK and ORK-LASIK

目的比较常规准分子激光原位角膜磨镶术(laserin situ keratomileusis,LASIK)和角膜波前像差引导的优化屈光角膜切削术(optimized refractive keratomy,ORK)后近视眼患者视力及角膜前表面高阶像差的变化,探讨角膜波前像差引导的优化准分子激光原位角膜磨镶术(ORK-LASIK)的安全性和有效性。方法选取拟做LASIK手术的近视眼患者396例733眼,按球镜屈光度分成低度(≤-3.00D)、中度(-3.00～-6.00D)和高度(-6.00～-12.00D)3组,每组柱镜度数均小于-2.50D,各组再随机分成2组,一组行常规LASIK手术,另一组行ORK-LASIK。手术切削区直径为6.0～7.0mm。角膜波前像差分析为6mm瞳孔直径。术后随访6个月,检查裸眼视力及角膜地形图并进行波前像差分析。结果成人近视眼角膜前表面波前像差在6mm瞳孔直径以3阶和4阶为主,占90%,在3阶和4阶中又以彗差和球差为主,分别占角膜全部像差的27.7%和28.4%;球差和球镜度数呈负相关(r=-0.501,P<0.05),其他高阶像差和球镜度数无关。但在-6.00D以上的近视眼中,彗差和次级彗差均和球镜度数有关(F=8.808,7.123,P<0.04,0.01)。角膜前表面各高阶像差均和年龄及性别无关。LASIK和ORK-LASIK2组比较,术后6个月时,低度和高度组2组的裸眼视力均达到术前矫正视力,差异无统计学意义(P>0.05);在中度组,ORK-LASIK组视力明显好于LASIK组,2组差异有统计学意义(P<0.05)。术后6个月时,角膜前表面的球差、彗差和总高阶像差均较术前增加,和术前比较差异有统计学意义(P<0.05)。在低度组,ORK-LASIK组和LASIK组比较角膜彗差和球差2组间差异无统计学意义(P>0.05);中、高度组ORK-LASIK组角膜彗差和球差较LASIK组明显下降,差异有统计学意义(P<0.05)。结论角膜波前像差引导的ORK-LASIK手术能有效地矫正近视和散光,提高中度近视患者的视力,降低中、高度组术后彗差和球差,手术效果稳定、安全。

Objective To compare the changes of higher order aberrations of anterior cornea after laser in situ keratomileusis（LASIK） and corneal wavefront aberrations guided optimized refractive keratomy-LASIK（ORK-LASIK） for treatment of myopia and discuss the safety and efficiency of ORK-LASIK for treatment of myopia. Methods Three hundreds and ninty-six eases of myopia were enrolled and presented into three groups according to their diopters of spherical refractive error （ low： more than 3.00 D; middle： from 3.00 D to 6.00 D;high：from 6.00 to 12.00 D）.The cases in each group were subdivided into two groups again according to their surgery method ：LASIK,ORK- LASIK. The ablation zone was from 6.0 to 7.0 mm. Wavefront aberrations were analyzed for 6.0 mm pupil zone. Results For 6 mm pupil, the characteristics and distributions of the Zernike coefficients and higher order root mean square （RMS） from the third to fifth order were described. The mean total contribution of each order to the total higher order RMS were as followed： 47% （ third ）, 43% （ fourth ） and 10% （flith）. Significant correlation was found between spherical aberration and refraction （ r = - 0. 501, P 〈 0.05 ）. There was statistically significant relations found in more than -6.00 D groups：coma and refraction （F = 8. 808, P 〈 0.04 ） ; Secondary coma and refraction（F= 7. 123 ,P 〈 0. 01 ）. There was no correlation between total higher order RMS and age or gender. All the cases after operation were followed up for 6 months, the coma, spherical aberration and higher order RMS of anterior cornea were increased than preoperation after both surgeries, especially after LASIK, and the difference was statistical significant （P 〈 0. 05 ）. The recovery of postoperative uncorrected visual acuity （UCVA） after ORK-LASIK and LASIK returned to the preoperative best corrected visual acuity （BCVA） in low and high groups and hadn＇ t increased significantly（ P 〈 0. 05 ）, but in the middle group, the UCVA of ORK-LASIK group was better than that of LASIK group and the difference was statistical significant（P 〈 0.05 ）. Conclusion ORK-LASIK is effective on correcting myopia and astigmatism. It can increase the UCVA of middle group, and decrease the RMS of anterior corneal coma and spherical aberration after surgery in middle group and high group. It is stable and safe.