Department of Ophthalmology, Eye and ENT Hospital, Fudan University and NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.
Clin Exp Optom. 2024 Nov;107(8):788-794. doi: 10.1080/08164622.2023.2300297. Epub 2024 Jan 16.
The detection of subclinical ectasia is important in preoperative screening for laser-refractive surgery. Previous studies have confirmed the impact of corneal diameter on the diagnostic accuracy of several ectasia indices in tomographically normal eyes.
This study aimed to investigate the influence of corneal diameter on the diagnostic accuracy of Pentacam tomographic indices in eyes with forme fruste keratoconus (FFKC) and thin corneas.
One hundred and one eyes of 101 patients with FFKC (FFKC group), 104 eyes of 104 patients with a corneal thickness <490 μm (thin cornea group), and 200 eyes of 200 normal subjects (normal group) were analysed in the study. Pentacam ectasia indices were compared between the groups.
The results of multiple linear regression analysis showed that the standardised coefficients for corneal diameter and overall deviation of normality (BAD-D) were -0.386, -0.552, and -0.552 for the FFKC, thin cornea, and normal groups, respectively ( < 0.001). Comparing for the classifications (normal versus abnormal) of the individual indices demonstrated that for corneal diameters ≤11.9 mm, the rates of abnormal cases were significantly higher in the FFKC group than in the normal group for seven indices and in the thin cornea group than normal group for nine indices. For corneal diameters >11.9 mm, the rates of abnormal cases were higher in the FFKC than normal group for three indices and higher in the thin cornea group than normal group for seven indices.
Belin/Ambrosio Enhanced Ectasia display indices may underestimate the risk of ectasia in patients with large corneas, especially those with FFKC.
在激光屈光手术的术前筛查中，亚临床扩张的检测很重要。先前的研究已经证实，角膜直径对几种在正常角膜地形图的眼的扩张指数的诊断准确性有影响。
本研究旨在探讨角膜直径对 forme fruste 圆锥角膜（FFKC）和薄角膜患者 Pentacam 断层扫描指数诊断准确性的影响。
本研究分析了 101 例 forme fruste 圆锥角膜患者的 101 只眼（FFKC 组）、104 例角膜厚度<490μm 的患者的 104 只眼（薄角膜组）和 200 例正常对照者的 200 只眼。比较各组之间 Pentacam 扩张指数。
多元线性回归分析的结果显示，角膜直径和整体偏离正态性（BAD-D）的标准化系数在 FFKC、薄角膜和正常组分别为-0.386、-0.552 和-0.552（均<0.001）。比较各指数（正常与异常）的分类结果表明，对于角膜直径≤11.9mm 的病例，在七个指数中，FFKC 组异常病例的发生率明显高于正常组，在九个指数中，薄角膜组异常病例的发生率明显高于正常组。对于角膜直径>11.9mm 的病例，在三个指数中，FFKC 组异常病例的发生率高于正常组，在七个指数中，薄角膜组异常病例的发生率高于正常组。
Belin/Ambrosio 增强扩张显示指数可能低估大角膜患者，特别是 forme fruste 圆锥角膜患者的扩张风险。
