Evaluation of corneal elevation, pachymetry and keratometry in keratoconic eyes with respect to the stage of Amsler-Krumeich classification
Evaluation of corneal elevation, pachymetry and keratometry in keratoconic eyes with respect to the stage of Amsler-Krumeich classification
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DOI：
10.1136/bjophthalmol-2013-304132
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发表时间：
2014-04-01
影响因子：
4.1
通讯作者：
Igarashi, Akihito
中科院分区：
文献类型：
--
作者：
Kamiya, Kazutaka;Ishii, Rie;Igarashi, Akihito
目的根据圆锥角膜的临床分期，评价圆锥角膜患者的角膜高度、角膜厚度和角膜曲率的变化。方法对83例126眼圆锥角膜患者和42例42眼正常人进行前瞻性对比研究。使用旋转Scheimpflug相机（Pentacam HR，Oculus）测量这些眼睛的角膜高度、角膜厚度和角膜曲率。受试者工作特征（AUROC）曲线下的面积被用来分析这些参数的诊断意义，相对于每个阶段的Amsler-Krumeich分类。计算AUROC以描述不同指标的预测准确性，并确定敏感性和特异性最大化的截断点。（0.980）和前部高度差（0.977）的AUROC值最高，其次是屈光度（D）值（0.941），厚度增加百分比（PTI）2 mm（0.931），PTI 4 mm（0.927），进展指数（0.927），最小厚度测量（0.923），平均角膜曲率（0.914），前抬高（0.909），PTI 6 mm（0.906），后抬高中心角膜厚度测量（0.889）、PTI 8 mm（0.870）、PTI 10 mm（0.864）、角膜厚度空间轮廓2 mm（0.835）和柱镜（0.796）。在圆锥角膜的早期阶段，前后高度差测量值和其他诊断参数之间的AUROC曲线差异有较大的趋势。结论通过增强扩张显示获得的前、后角膜表面高度数据，可以有效区分圆锥角膜和正常角膜。高度差测量可提供有用的信息，以提高圆锥角膜的诊断准确性，特别是在疾病的早期阶段。
Aim To evaluate corneal elevation, pachymetry and keratometry in keratoconic eyes according to the clinical stage of the disease.Methods This prospective comparative study was performed on one hundred and twenty-six eyes of 83 patients who had keratoconus, and 42 normal eyes of 42 age-matched subjects. Corneal elevation, pachymetry and keratometry were measured using a rotating Scheimpflug camera (Pentacam HR, Oculus) in these eyes. The area under the receiver operating characteristic (AUROC) curves was used to analyse the diagnostic significance of these parameters, with respect to each stage of Amsler-Krumeich classifications. AUROC was calculated to describe the predictive accuracy of the different indices and to determine the cut-off points where sensitivity and specificity were maximised.Results Posterior (0.980) and anterior (0.977) elevation differences showed the highest AUROCs, followed by dioptres (D) value (0.941), percentage thickness increase (PTI) 2 mm (0.931), PTI 4 mm (0.927), progression index (0.927), minimal pachymetry (0.923), average keratometry (0.914), anterior elevation (0.909), PTI 6 mm (0.906), posterior elevation (0.898), central pachymetry (0.889), PTI 8 mm (0.870), PTI 10 mm (0.864), corneal thickness spatial profile 2 mm (0.835) and cylinder (0.796). The differences in AUROC curves between anterior and posterior elevation difference measurements and other diagnostic parameters tended to be larger at the earlier stages of keratoconus.Conclusions Anterior and posterior corneal surface height data obtained by enhanced ectasia display, effectively discriminates keratoconus from normal corneas. Elevation difference measurements may provide useful information for improving the diagnostic accuracy of keratoconus, especially in the early stage of the disease.