Pakbin Mojgan, Khabazkhoob Mehdi, Pakravan Mohammad, Fotouhi Akbar, Jafarzadehpur Ebrahim, Aghamirsalim Mohamadreza, Hashemi Hassan
Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
Translational Ophthalmology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
J Curr Ophthalmol. 2022 Apr 16;34(1):50-55. doi: 10.4103/joco.joco_173_21. eCollection 2022 Jan-Mar.
To determine the repeatability of corneal densitometry measured by the Scheimpflug imaging system.
This cross-sectional study was conducted on photorefractive keratectomy candidates. One eye of each participant underwent imaging using Pentacam HR three times, 10 min apart. The repeatability of densitometry measurements was evaluated in four concentric annuli around the corneal apex and in different corneal depths. The repeatability of the measurements was evaluated using the intraclass correlation coefficient (ICC), repeatability coefficient (RC), and coefficient of variation (CV). The difference of repeatability between layers and zones was tested by tolerance index (TI).
Sixty eyes of sixty patients with a mean age of 27.76 ± 3.93 years were studied. Half of the participants were female ( = 30, 50%). ICC was above 0.9 in all corneal parts. The posterior layer and central zones showed the least variability of densitometry measurements considering the CV values. The RC was 2.06, 1.17, and 0.92 in anterior, central, and posterior layers, respectively. The RC was 0.88, 0.71, 1.51, and 4.56 in 0-2, 2-6, 6-10, and 10-12 mm circles, respectively. Only the reliability of densitometry in 10-12 mm annulus was statistically lower than the central zone (TI = 0.71).
Corneal densitometry measurements provided by the Pentacam had good repeatability. The repeatability of densitometry measurements decreased from the center to the periphery (with an exception for 0-2 mm and 2-6 mm) and from the posterior to the anterior of the cornea. The reliability of the 10-12 mm zone was markedly less than other zones.
确定通过Scheimpflug成像系统测量角膜密度的可重复性。
本横断面研究针对准分子激光原位角膜磨镶术（PRK）候选者进行。每位参与者的一只眼睛使用Pentacam HR进行三次成像，每次间隔10分钟。在角膜顶点周围的四个同心环带以及不同的角膜深度评估密度测量的可重复性。使用组内相关系数（ICC）、重复性系数（RC）和变异系数（CV）评估测量的可重复性。通过耐受指数（TI）测试各层和各区之间重复性的差异。
研究了60例患者的60只眼睛，平均年龄为27.76±3.93岁。一半参与者为女性（n = 30，50%）。所有角膜部位的ICC均高于0.9。考虑CV值，后层和中央区域的密度测量变异性最小。前层、中央层和后层的RC分别为2.06、1.17和0.92。在0 - 2、2 - 6、6 - 10和10 - 12 mm环带中的RC分别为0.88、0.71、1.51和4.56。仅10 - 12 mm环带中密度测量的可靠性在统计学上低于中央区域（TI = 0.71）。
Pentacam提供的角膜密度测量具有良好的可重复性。密度测量的可重复性从角膜中心到周边降低（0 - 2 mm和2 - 6 mm除外），从角膜后层到前层降低。10 - 12 mm区域的可靠性明显低于其他区域。
