Thulasidas Mithun, Teotia Prateek
Cornea, Cataract and Refractive Surgery Services, Centre for Sight Eye Institute, New Delhi, India.
Indian J Ophthalmol. 2020 Nov;68(11):2415-2420. doi: 10.4103/ijo.IJO_2129_19.
To analyse topographic and tomographic changes in fellow eyes of unilateral keratoconus patients by comparing them with normal eyes.
This five-year retrospective observational comparative case study included 15 advanced keratoconus eyes of unilateral keratoconus (KCN group), 15 normal fellow eyes of unilateral keratoconus (Fellow eye group) and 34 eyes of normal refractive surgery candidates (Normal group). Topographic and tomographic data, data from enhanced elevation maps, and keratoconus indices were measured in all study eyes using Pentacam. Receiver operating characteristic (ROC) curves were used to evaluate the area under the curve (AUC), sensitivity and specificity of each parameter and identify cut-off points in discriminating between the fellow and normal eyes.
Corneal thickness at the apex (CTA, P = 0.001) and at the thinnest point (CTT, P < 0.001), corneal volume (CV, P = 0.007), Belin/Ambrosio Enhanced Ectasia Display (BAD) - thinnest point (Dt, P = 0.002) and thinnest point displacement (Da, P = 0.002) were significantly lower in the fellow group compared to eyes of normal subjects. On ROC curve analysis, the most efficient distinguishing indices between the fellow group and normal controls were BAD - overall D value (AUC = 0.859), Dt (AUC =0.827), Da (AUC = 0.789) followed by pachymetric progression index maximum (AUC = 0.741).
BAD-D value and pachymetric progression index could be useful in detecting the earliest form of subclinical keratoconus. However, every single parameter alone is not enough to detect early changes; a combination of different data is required to distinguish subclinical keratoconus.
通过将单眼角膜圆锥角膜患者的对侧眼与正常眼进行比较，分析其地形学和断层扫描变化。
这项为期五年的回顾性观察性比较病例研究包括15只单眼角膜圆锥角膜的晚期圆锥角膜眼（圆锥角膜组）、15只单眼角膜圆锥角膜的正常对侧眼（对侧眼组）和34只正常屈光手术候选者的眼睛（正常组）。使用Pentacam测量所有研究眼的地形学和断层扫描数据、增强高度图数据以及圆锥角膜指数。采用受试者操作特征（ROC）曲线评估每个参数的曲线下面积（AUC）、敏感性和特异性，并确定区分对侧眼和正常眼的临界点。
与正常受试者的眼睛相比，对侧眼组的角膜顶点厚度（CTA，P = 0.001）和最薄点厚度（CTT，P < 0.001）、角膜体积（CV，P = 0.007）、贝林/安布罗西奥增强扩张显示（BAD）-最薄点（Dt，P = 0.002）和最薄点位移（Da，P = 0.002）显著更低。在ROC曲线分析中，对侧眼组与正常对照组之间最有效的区分指标是BAD-总体D值（AUC = 0.859）、Dt（AUC = 0.827）、Da（AUC = 0.789），其次是测厚进展指数最大值（AUC = 0.741）。
BAD-D值和测厚进展指数可能有助于检测亚临床圆锥角膜的最早形式。然而，单一参数不足以检测早期变化；需要结合不同数据来区分亚临床圆锥角膜。
