From the Imaging, Biomechanics and Mathematical Modelling Solutions, Narayana Nethralaya Foundation (M.F., A.S.R.), Bangalore, India; Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India.
Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India.
Am J Ophthalmol. 2023 Dec;256:175-185. doi: 10.1016/j.ajo.2023.08.017. Epub 2023 Sep 3.
To define the external scleral sulcus (ESS) on a Scheimpflug image and use it for a morphometric analysis of corneal diameter (CD).
Retrospective, cross-sectional study of pediatric Asian-Indian eyes.
One random eye of 353 subjects between 5 and 18 years underwent 25-scan Pentacam HR imaging. For all scans, densitometry values along the anterior corneal edge were recorded and differentiated. The peaks on the differentiated curve were chosen as the ESS points, and this distance between them was called CD. Vertical (vCD), maximum (maxCD), minimum (minCD) CD and their meridians were defined. Multiple regression models (MRMs) with CD and other Pentacam parameters were built to predict astigmatism and its axis, mean keratometry (Kmean), and Belin/Ambrósio enhanced ectasia display deviation (BAD-D). MRMs were validated using intraclass correlation coefficient (ICC). Estimated horizontal CD (hCD) was validated against digital caliper measurement using ICC.
The ICC (95% CI) between caliper and hCD was 0.96 (0.93, 0.97). MRM predictions (P < .001) used CD parameters, anterior chamber depth, corneal volume and distance from the corneal thinnest location to apex. These predictions achieved an ICC of 0.34 (0.18, 0.46), 0.82 (0.78, 0.86), 0.87 (0.84, 0.89), and 0.81 (0.76, 0.84), respectively. The astigmatism axis prediction depended on the minCD and maxCD meridians. Its within-subject SD (4.97°) was less than 2 consecutive Pentacam scan angles (7.2°).
The CD metric strongly correlated with the astigmatism axis, keratometry, and BAD-D. Its spatial description may be significant in corneal treatment planning and disease diagnoses.
定义 Scheimpflug 图像中的外部巩膜沟（ESS），并将其用于角膜直径（CD）的形态分析。
对 353 名 5 至 18 岁亚洲印度裔儿童的眼部进行回顾性、横断面研究。
对 353 名受试者的 353 只随机眼进行 25 扫描 Pentacam HR 成像。对所有扫描，记录并区分前角膜缘的密度测量值。选择分化曲线上的峰值作为 ESS 点，它们之间的距离称为 CD。定义垂直（vCD）、最大（maxCD）、最小（minCD）CD 及其子午线。建立包含 CD 和其他 Pentacam 参数的多元回归模型（MRM），以预测散光及其轴、平均角膜曲率（Kmean）和 Belin/Ambrósio 增强扩张显示偏差（BAD-D）。使用组内相关系数（ICC）验证 MRM。使用 ICC 验证估计的水平 CD（hCD）与数字卡尺测量值的相关性。
卡尺与 hCD 的 ICC（95%CI）为 0.96（0.93，0.97）。MRM 预测（P<0.001）使用 CD 参数、前房深度、角膜体积和从角膜最薄位置到顶点的距离。这些预测的 ICC 分别为 0.34（0.18，0.46）、0.82（0.78，0.86）、0.87（0.84，0.89）和 0.81（0.76，0.84）。散光轴的预测取决于 minCD 和 maxCD 子午线。其个体内标准差（4.97°）小于 2 次连续 Pentacam 扫描角度（7.2°）。
CD 指标与散光轴、角膜曲率和 BAD-D 高度相关。其空间描述在角膜治疗计划和疾病诊断中可能具有重要意义。
