Nuri Eye Hospital, Deajeon, Korea.
Kim's Eye Hospital, Seoul, Korea.
PLoS One. 2022 Sep 1;17(9):e0274071. doi: 10.1371/journal.pone.0274071. eCollection 2022.
This study aimed to evaluate and compare the discriminating ability of corneal elevation maps generated using a swept-source optical coherence tomography (SS-OCT) (SS-OCT ANTERION, Heidelberg Engineering, Heidelberg, Germany), which was estimated with different reference surfaces, to distinguish normal corneas from those with keratoconus and keratoconus suspect.
A total of 126 eyes of patients, which comprised 43, 37, and 46 keratoconus, keratoconus suspects, and normal controls, respectively, were included in this study. The anterior and posterior elevations at the thinnest point under the best-fit sphere (BFS) and toric-ellipsoid (BFT), respectively, and other corneal parameters were measured using the SS-OCT. In addition, the receiver operating characteristic (ROC) curve analysis and cut-off value were calculated to evaluate the diagnostic ability of the corneal elevation values in differentiating keratoconus and keratoconus suspects from normal eyes.
The mean total keratometric and corneal elevation values were significantly higher in the keratoconus group than in the other groups. Pachymetric parameters exhibited the lowest values for keratoconus. In addition, ROC curve analyses showed a high accuracy of the thinnest point anterior and posterior BFT for both keratoconus and keratoconus suspects and normal controls (area under the ROC were 0.969 and 0.961, respectively). Furthermore, the optimal cut-off point of the posterior elevation at the thinnest point under BFT was 16.44 μm (sensitivity and specificity of 86% and 98%, respectively) for differentiating keratoconus from normal and keratoconus suspect eyes.
The elevation map using the BFS and BFT references measured with the anterior segment SS-OCT is considered an effective indicator for keratoconus diagnosis. Therefore, the anterior segment SS-OCT can effectively differentiate keratoconus from suspected keratoconus and normal corneas by measuring parameters such as posterior and anterior elevations, pachymetry, and keratometry.
本研究旨在评估和比较使用扫频源光学相干断层扫描（SS-OCT）（德国海德堡工程公司的 SS-OCT ANTERION）生成的角膜高度图的区分能力，该高度图使用不同的参考面进行估计，以区分正常角膜与圆锥角膜和疑似圆锥角膜。
本研究共纳入 126 只眼，分别为 43 只、37 只和 46 只圆锥角膜、疑似圆锥角膜和正常对照组。使用 SS-OCT 分别测量最佳拟合球（BFS）下最薄点的前、后高度（BFT）以及其他角膜参数。此外，还计算了受试者工作特征（ROC）曲线分析和截断值，以评估角膜高度值在区分圆锥角膜和疑似圆锥角膜与正常眼方面的诊断能力。
圆锥角膜组的总角膜曲率和角膜高度平均值明显高于其他组。角膜厚度参数在圆锥角膜组中最低。此外，ROC 曲线分析显示，最薄点前、后 BFT 的高度对于区分圆锥角膜和疑似圆锥角膜以及正常对照组具有较高的准确性（ROC 曲线下面积分别为 0.969 和 0.961）。此外，最佳截断点为最薄点 BFT 后高度 16.44μm（区分圆锥角膜与正常和疑似圆锥角膜的敏感性和特异性分别为 86%和 98%）。
使用 SS-OCT 前节测量的 BFS 和 BFT 参考的高度图被认为是诊断圆锥角膜的有效指标。因此，前节 SS-OCT 通过测量后、前高度、角膜厚度和角膜曲率等参数，可有效区分圆锥角膜与疑似圆锥角膜和正常角膜。
