角膜内皮移植前后角膜高阶像差与视力的相关分析

Correlation analysis of visual acuity and higher order aberrations of the anterior and posterior cornea before and after endothelial keratoplasty

目的探讨角膜内皮移植手术前后角膜高阶像差的变化,并分析术后角膜前后表面高阶像差对视力的影响。方法角膜内皮移植术前1个月及术后3个月,采用Orbscan角膜地形图系统测量18例19眼(内皮移植组)的角膜中央4mm区域的高阶像差数据,并以Zernike多项式方式计算6阶以内像差,计算总高阶像差的均方根和3阶至6阶像差的均方根,并取同期无角膜疾病的正常眼10例19眼为对照组进行比较。内皮移植组术后3个月的角膜前后表面总高阶像差均方根与logMAR视力的关系采用直线相关分析。结果术后角膜前后表面总高阶像差均方根较术前显著降低(均为P<0.05)。术后3个月最佳矫正视力与角膜前表面总高阶像差均方根呈正相关(r=0.927,P<0.01),而与角膜后表面总高阶像差均方根无相关(r=0.326,P>0.05)。结论角膜内皮移植术后最佳矫正视力与术后角膜前表面不规则性相关,而与后表面不规则性无相关。角膜前表面高阶像差是影响内皮移植术后视力的主要因素。

Objective To evaluate changes of higher order aberrations of the anterior and posterior cornea before and after endothelial keratoplasty（DSEK）and its effect on visual acuity.Methods The aberration data in a 4 mm diameter region of the middle of the cornea of 19 consecutive eyes of 18 cases（DSEK group）were collected by using an Orbscan topography on 1 month before DSEK and 3 months after DSEK.The data were decomposed into a set of Zernike polynomials up to the 6th order.Root mean square（RMS）of total higher order and the 3rd to 6th order aberrations were calculated.Nineteen eyes of 10 cases were chosen as control group without any cornea disease.The relations between anterior and posterior surface total higher order aberrations and logMAR vision were evaluated by linear correlation analysis.Results The RMS of total higher order aberrations of the anterior and posterior cornea after operation was significantly lower than that before operation（P0.05）.The best corrected visual acuity after operation has positive correlation with higher order aberrations of the anterior cornea（r=0.927,P0.01）.There was no correlation with visual acuity after operation and the higher order aberrations of the posterior surface（r=0.326,P0.05）.Conclusion The best corrected visual acuity after operation is positively correlated with the irregular anterior surface of the cornea,but not with the posterior surface.The higher order aberrations of the anterior cornea is an important influencing factor for vision after DSEK.