超高分辨率OCT测量角膜上皮层厚度在圆锥角膜诊断中的价值

摘要

目的 探讨超高分辨率OCT测量的角膜上皮层厚度参数在圆锥角膜诊断中的价值.方法 横断面研究.选取圆锥角膜患者20例(20眼)和同期健康志愿者20例(20眼).应用自行搭建的超高分辨率OCT测量所有受检者的角膜上皮层厚度,获取垂直子午线上全角膜上皮厚度平均值(MEAN)、角膜上皮下方厚度最小值(MIN)、角膜上皮下方厚度最小值/上方厚度平均值×100(EEI)、角膜上皮下方厚度最小值/上方厚度最大值×100(EEI-MAX)、以自身平均值为标准的各区域差值均方根(ESV)等5个诊断参数.采用独立样本t检验对数据进行统计比较,通过受检者工作特征(ROC)曲线对测量参数的诊断性能和诊断价值进行评估.结果 角膜上皮层厚度参数中正常组的MEAN、MIN、EEI、EEI-MAX 、ESV值分别为(52.52±2.64)μm、(50.05±3.38) μm、97.93±4.59、91.60±4.54、2.94±0.56.圆锥角膜组则分别为(51.33±3.78) μm、(38.86±5.45) μm 、77.13±10.59、67.45± 12.64、7.02±2.55.其中ESV值的诊断性能和诊断价值最高,其ROC曲线下面积和阳性预测值均达到最大值1.000.MIN、EEI、EEI-MAX次之,其ROC曲线下面积分别为0.955、0.945、0.950,阳性预测值分别为0.900、0.900、0.950,均≥0.900.结论 圆锥角膜患者的垂直子午线上全角膜上皮层厚度在中央以及下方偏中央区域变薄,下方周边增厚.OCT角膜上皮层厚度参数在圆锥角膜诊断中有一定的临床指导价值.其中ESV值的诊断性能和诊断价值最高.%Objective To investigate the role of the corneal epithelial thickness (EP) parameters measured with ultra-high resolution optical coherence tomography (UHR-OCT) in the diagnosis of keratoconus.Methods In this cross-sectional observational study,20 patients with keratoconus (20 eyes) and 20 normal volunteers (20 eyes) were recruited in the study.Corneal epithelial thickness profiles were taken from all subjects.The parameters included mean thickness (MEAN),minimum thickness (MIN),epithelial ectasia index (EEI),defined as epithelial thickness minimum thickness of the inferior half of the cornea divided by corneal epithelial thickness average thickness of the superior half of the cornea multiplied by 100,maximal epithelial ectasia index (EEI-MAX),defined as corneal epithelial thickness minimum thickness of the inferior half of the cornea divided by corneal epithelial thickness maximum thickness of the superior half of the cornea multiplied by 100,epthetlium standard variation (ESV).Statistical analysis methods included independent samples t-test and receiver operating characteristic (ROC) curves.Results In normal eyes,the MEAN,MIN,EEI,EEI-MAX,ESV were 52.52±2.64 μm,50.05±3.38 μm,97.93±4.59,91.60±4.54,2.94±0.56.In keratoconic eyes,they were 51.33±3.78 μm,38.86±5.45 μm,77.13±10.59,67.45±12.64,7.02±2.55.Among the epithelial pachymetry parameters,ESV showed highest diagnostic efficiency and diagnostic value for keratoconus,the area under the ROC curve (AUC) was 1.000 and the positive predictive value was 1.000.MIN,EEI,EEI-MAX also have high diagnostic efficiency and diagnostic value,the AUC were 0.955,0.945,0.950,and the positive predictive value were 0.900,0.900,0.950.Conclusion keratoconus is characterized by central and inferior epithelial thinning surrounded by thickened epithelium.The epithelial pachymetry parameters show excellent accuracy,sensitivity,and specificity in the diagnosis of keratoconus,especially the ESV.