应用iTrace视觉功能分析仪测量双眼角膜像差的一致性

目的　探讨正常人群双眼角膜像差的一致性及其影响因素。方法　观察性研究分析。随机选取中国医科大学附属第四医院2016年12月至2017年12月进行体格检查的健康人群240人（480眼），年龄10~70岁，每隔10岁分一组，共分为6组，每组40人，对纳入研究的人群使用iTrace视觉功能分析仪分别测量双眼角膜地形图及波前像差，收集每个人在2 mm、3 mm、4 mm、5 mm瞳孔直径下双眼的角膜像差，包括水平三叶草差（Z₃³）、垂直三叶草差（Z₃^-3）、水平四叶草差（Z₄⁴）、垂直四叶草差（Z₄^-4）、水平彗差（Z₃¹）、垂直彗差（Z₃^-1）、水平二次散光（Z₄²）、垂直二次散光（Z₄^-2）、球差（Z₄⁰），采用配对t检验比较双眼指标间的差异；Pearson相关分析探讨双眼各像差的相关性，Bland-altman比较双眼总角膜像差的一致性。结果　总角膜像差在双眼间存在镜像对称并具有一致性，但在不同条件下，双眼角膜像差存在差异:2 mm和3 mm瞳孔直径下，除Z₃³双眼间差异具有统计学意义（均为P<0.05）外，其余像差双眼间差异均无统计学意义（均为P>0.05）；4 mm瞳孔直径下，Z₃¹、Z₄^-4、Z₄² 双眼间差异均具有统计学意义（均为P<0.05）；5 mm瞳孔直径下，Z₃¹、Z₄^-4、Z₄² 双眼间差异均具有统计学意义（均为P<0.05）；Z₄⁰ 最为稳定，在双眼间的一致性和相关性最高。随着年龄的增加，三叶草差、彗差双眼间的差值均逐渐增大，四叶草差、二次散光、球差随年龄的增加在双眼间变化微小。结论　总角膜像差在双眼间具有一致性，但在不同瞳孔直径下双眼角膜像差存在差异。

Consistency analysis on the corneal aberration expressed by iTrace visual function analyzer

Objective　To investigate the consistency and related factors of corneal aberration in normal human eyes.Methods　An observational study was conducted.A total of 240 healthy peopleaged 10-70 years after physical examination at the Fourth Affiliated Hospital of China Medical University from December 2016 to December 2017 were randomly selected，and divided those people into 6 groups every 10 years，40 people in each group.The iTrace visual function analyzer was used to measure the corneal topography and wave-front aberration in two eyes.Corneal aberrations of each person were collected at 2 mm，3 mm，4 mm，5 mm pupil diameter，including horizontal trefoil （Z₃³），vertical trefoil （Z₃^-3），horizontal tetrafoil （Z₄⁴），vertical tetrafoil （Z₄^-4），horizontal coma （Z₃¹），vertical coma （Z₃^-1），horizontal secondaryastigmatism（Z₄²），vertical secondary astigmatism （Z₄^-2），spherical aberration （Z₄⁰）.Paired t-test was used to compare the differences between two eyes，Pearson’s analysis to explore the correlation between two eyes，and Bland-altman was applied to compare the consistency of total corneal aberration between two eyes.Results　Total corneal aberration was mirror symmetrical and had consistency between two eyes，but there had differences results under different conditions:For 2 mm and 3 mm pupil diameter，only Z₃³ had statistically significant difference （P<0.05），there was no significant difference in other aberrations between two eyes （all P>0.05）.For 4 mm pupildiameter，Z₃¹，Z₄^-4 and Z₄² had statistically significant difference （all P<0.05）.For 5 mm pupil diameter，Z₃¹，Z₄^-4，Z₄² had statistically significant difference （all P<0.05）.Z₄⁰ had the highest consistency and correlation between two eyes.With the increase of age，the differences between two eyes were gradually increased in trefoil and coma，but the differences of tetrafoil，secondary astigmatism，spherical aberration showed very slight variations between two eyes.Conclusion　The total corneal aberration has consistency between two eyes，but for every single corneal aberration，different conditions get different results.