Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Department of Ophthalmology, Baptist Eye Institute, Kyoto, Japan.
PLoS One. 2020 Apr 2;15(4):e0231074. doi: 10.1371/journal.pone.0231074. eCollection 2020.
To evaluate the diagnostic ability of the ratio of anterior and posterior corneal surface areas (As/Ps) comparing with other keratoconus screening indices in distinguishing forme fruste keratoconus (FFKC) from normal eyes.
In this comparative study, 13 eyes of 13 patients with FFKC, 29 eyes of 29 patients with keratoconus (KC) and 88 eyes of 88 patients with normal subjects were involved. The As/Ps measured by the anterior segment optical coherence tomography (AS-OCT) and other indices measured by AS-OCT and rotating Scheimpflug-based corneal tomography were evaluated. The area under receiver-operating-characteristics (AU-ROC) was calculated to assess the diagnostic ability in discriminating FFKC from normal eyes.
The As/Ps, the Belin/Ambrosio display enhanced ectasia total derivation value (BAD-D) and posterior and anterior elevation values showed the AU-ROC 0.9 or more in differentiating FFKC from normal eyes (0.980, 0.951, 0.924 and 0.903, respectively). The sensitivity and specificity were 0.92 and 0.96 for the As/Ps, 1.00 and 0.90 for BAD-D, 0.85 and 0.86 for posterior elevation value, and 0.85 and 0.96 for anterior elevation value, respectively.
Among the several indices for keratoconus screening which we evaluated, the As/Ps obtained by AS-OCT had the large AU-ROC with high sensitivity and specificity in detecting FFKC, which was comparable with BAD-D obtained by rotating Scheimpflug-based corneal tomography. The As/Ps may provide information for improving the diagnostic accuracy of KC, even in the initial stage of the disease.
评估角膜前、后表面面积比（As/Ps）与其他圆锥角膜筛查指标在区分早期圆锥角膜（FFKC）与正常眼方面的诊断能力。
本对比研究纳入 13 例（13 只眼）FFKC 患者、29 例（29 只眼）圆锥角膜（KC）患者和 88 例（88 只眼）正常对照者。采用眼前节光学相干断层扫描（AS-OCT）测量 As/Ps，采用 AS-OCT 和旋转 Scheimpflug 角膜断层扫描测量其他指标。计算受试者工作特征（ROC）曲线下面积（AU-ROC）评估区分 FFKC 与正常眼的诊断能力。
As/Ps、Belin/Ambrosio 显示扩展总偏差值（BAD-D）和后、前表面高度值在区分 FFKC 与正常眼方面具有 AU-ROC 0.9 或更高（分别为 0.980、0.951、0.924 和 0.903）。As/Ps 的灵敏度和特异度分别为 0.92 和 0.96、BAD-D 为 1.00 和 0.90、后表面高度值为 0.85 和 0.86、前表面高度值为 0.85 和 0.96。
在我们评估的几种圆锥角膜筛查指标中，AS-OCT 获得的 As/Ps 在检测 FFKC 方面具有较大的 AU-ROC，灵敏度和特异度均较高，与旋转 Scheimpflug 角膜断层扫描获得的 BAD-D 相当。As/Ps 可为提高 KC 的诊断准确性提供信息，即使在疾病的早期阶段。
