中老年白内障患者中角膜高阶波前像差与眼轴长度相关性变化

目的 调查我国中老年白内障患者角膜高阶波前像差分布的特点,探讨眼轴长度是否对角膜高阶波前像差产生影响,为白内障手术非球面人工晶状体的选择提供参考.方法 前瞻性临床研究.使用iTrace视觉功能分析仪测量319例319只优势眼的角膜前表面高阶像差,使用IOL Master测量眼轴长度,并按眼轴长度(AL)分为短眼轴组、正视及轻度近视组、高度近视组3组.记录6 mm瞳孔直径下的总高阶像差(HOAs)、彗差(coma aber-ration)、球差(spherical aberration)、三叶草像差(trefoil aberraition)的均方根值(RMS).分析角膜总高阶像差、彗差、球差、三叶草像差与眼轴长度的关系.结果 短眼轴组HOAs平均值为(0.586±0.593)μm,正视及轻度近视组HOAs平均值为(0.428±0.320)μm,高度近视组HOAs平均值为(0.680±0.518)μm,正视及轻度近视组及高度近视组与短眼轴组HOAs比较无明显差异,正视及轻度近视组与高度近视组HOAs差异有统计学意义(u=-0.840,P=0.401;u=-1.845,P=0.065;u=-3.185,P=0.001);短眼轴组彗差平均值为(0.184±0.148)μm,正视及轻度近视组彗差平均值为(0.158±0.111)μm,高度近视组彗差平均值为(0.265±0.216)μm,短眼轴组三叶草像差平均值为(0.177±0.140)μm,正视及轻度近视组三叶草像差平均值为(0.155±0.102)μm,高度近视组三叶草像差平均值为(0.299±0.256)μm,短眼轴组球差平均值为(0.030±0.140)μm,正视及轻度近视组球差平均值为(0.010±0.119)μm,高度近视组球差平均值为(0.025±0.099)μm,3组间彗差、三叶草像差的差异均有统计学意义(F=12.321,F=20.515,P=0.000),3组间球差的差异无统计学意义(F=0.911,P=0.403).结论 研究表明我国中老年白内障患者中不同眼轴长度分组的瞳孔中央6 mm直径的角膜总高阶像差、彗差及三叶草像差存在着一定的差异,当AL≥25.00 mm时,总高阶像差、彗差及三叶草像差明显增大,而在不同眼轴长度分组中球差未发现明显差异.角膜球差具有较大个体差异性且未发现与眼轴有任何相关性,手术前角膜球差的精准测量是非球面人工晶状体个性化选择的必要步骤.

Correlations between higher-order corneal wavefront aberration and axial length in middle aged and elderly Chinese population

Objective To investigate the relationship between higher-order corneal wavefront aberrations with dif-ferent axial length in middle aged and elderly Chinese population,and to help aspheric intraocular lens choice based on these information. Methods This was a prospective clinical study. We analyzed 319 eyes from patients without corneal diseases. Average astigmatism was less than 1. 00 D. Patients were divided into three groups based on axial length (AL):short AL (group 1),normal AL (group 2),and long AL (group 3). Corneal aberrations were measured with iTrace. Axi-al length was measured with IOL master. Higher-order aberrations,coma,spherical and trefoil aberrations were compared among the three groups over 6 mm areas. Results Average total higher-order aberration was only significantly different be-tween the group 2 and 3 (u = - 3. 185,P = 0. 001). Significant differences in coma aberration and trefoil aberration were observed among three groups (F = 12. 321,F = 20. 515;both P < 0. 01). There was no difference in spherical aberration (F = 0. 911,P = 0. 403). Conclusion These results suggested that the total higher-order aberrations,coma aberration and trefoil aberration increase with axial length,especially in the patients with axis length of more than 25 mm. Variability in corneal spherical aberration was common. Therefore,precise measurement of spherical aberration before surgery is cruci-al for the selection of aspheric intraocular lens.