显微定量角膜检查镜临床应用的评估

目的通过多家眼科单位对显微定量角膜检查镜（简称角膜镜）的临床试用检验角膜镜检查角膜散光度的准确性和稳定性。方法前瞻性多中心临床试验研究。4家眼科单位分别用角膜镜和角膜曲率计对被检者156例156眼（均取右眼）进行角膜散光测量,其中角膜镜每眼测3次,角膜曲率计每眼测1次,将角膜镜测量均值与角膜曲率计测量值进行比较,采用组内相关系数分析角膜镜3次测量间的稳定性,采用Bland-Altman散点图评价角膜镜与角膜曲率计测量散光度的准确性和一致性。结果角膜镜与角膜曲率计测量角膜散光度均值分别为（-1.96±1.16）D和（-1.84±1.17）D,二者呈高度线性相关（r=0.929,P=0.000）,配对t检验示二者差异有统计学意义（t=-3.020,P=0.003）。角膜镜与角膜曲率计测量角膜散光度差值为（-0.12±0.44）D。角膜镜与角膜曲率计测量角膜散光轴向的中位数均为0°,配对Wilcoxon符号秩检验示差异无统计学意义（Z=-1.775,P=0.076）。单因素方差分析显示角膜镜散光度3次测量间差异无统计学意义（F=0.153,P=0.859）。角膜镜对角膜散光度测量的组内相关系数（ICC）为0.975,对角膜散光轴向测量的ICC为0.988。角膜镜和角膜曲率计测量角膜散光度的一致性范围（差值均数±1.96SD）为（-1.00,0.76）D;将测量范围0～-8D分为0～、-1D～、-2D～、-4～-8D组段,结果显示角膜镜和角膜曲率计对各组段散光度测量的一致性范围均小于或接近于1.0D。结论角膜镜测量角膜散光度具有良好的准确性和稳定性。

Clinical evaluation of application of quantitative micro-keratoscope

Background Research showed that quantitative micro-keratoscope（keratoscope for short）is a portable quantitative astigmatism instrument for ocular micro-surgery.Though a series studies on the accuracy and repeatability of keratoscope have been performed,there are lack multi-center clinical study and a systematic statistical method.ObjectivePurpose of this clinical trial was to evaluate the accuracy and stability of keratoscope in the measurement of corneal astigmatism in multi-units.MethodsThis was a perspective,multi-center clinical study.Keratoscope and keratometer were used respectively to inspect the corneal astigmatism in 156 right eyes from 156 subjects with corneal astigmatism.The clinical trial was finished in 4 hospitals of Zhejiang province.The mean values from three repeated measurement were obtained by using the keratoscope,and one value of keratometer was accepted.The astigmatism diopter values and meridian between two measured methods were compared,and the reliability of astigmatism diopter values and meridian in keratoscope group were assessed using intraclass correlation coefficient.The accuracy and agreement between keratometer and keratoscope were evaluated with Bland-Altman plot.Written informed consent was obtained from each patient prior to any medical procedure relevant to this trial.ResultsThe astigmatism value obtained by keratoscope was（-1.96±1.16）D and that by keratometer was（-1.84±1.17）D,showing a significant difference（t=-3.02,P=0.003）and positive correlation between them（r=0.929,P0.01）.The mean difference of astigmatism value measured between keratoscope and keratometer was（-0.12±0.44）D.The median of astigmatism meridian from keratoscope and keratometer both were 0° with insignificantly difference（Z=-1.775,P=0.076）.No evidently difference was seen in the repeated measuring results by keratoscope（F=0.153,P=0.859）.The intraclass correlation coefficient of astigmatism values was 0.975,and that of astigmatism meridian was 0.988 in keratoscope group.The limits of agreement（mean difference±1.96SD）of astigmatism difference between two methods was（-1.00,0.76）D.When the measureing range（0--8D）of astigmatism diopter was divided into0—,-1D—,-2D—,-4—-8D,the LoA of each group was lower than or close to 1.0D.ConclusionThe quantitative micro-keratoscope occupies the characters of both accuracy and stability.