Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
Biophysics Interdisciplinary Group, The Ohio State University, Columbus, OH, USA.
Transl Vis Sci Technol. 2020 Dec 18;9(13):33. doi: 10.1167/tvst.9.13.33. eCollection 2020 Dec.
The purpose of this study was to establish in vivo data acquisition and processing protocols for repeatable measurements of heartbeat-induced corneal displacements and strains in human eyes, using a high-frequency ultrasound elastography method, termed ocular pulse elastography (OPE).
Twenty-four volunteers with no known ocular diseases were recruited for this study. Intraocular pressure (IOP) and ocular pulse amplitude (OPA) were measured using a PASCAL Dynamic Contour Tonometer (DCT). An in vivo OPE protocol was developed to measure heartbeat-induced corneal displacements. Videos of the central 5.7 mm of the cornea were acquired using a 50-MHz ultrasound probe at 128 frames per second. The radiofrequency data of 1000 frames were analyzed using an ultrasound speckle tracking algorithm to calculate corneal displacements and quantify spectral and temporal characteristics. The intrasession and intersession repeatability of OPE- and DCT-measured parameters were also analyzed.
The in vivo OPE protocol and setup were successful in tracking heartbeat-induced corneal motion using high-frequency ultrasound. Corneal axial displacements showed a strong cardiac rhythm, with good intrasession and intersession repeatability, and high interocular symmetry. Corneal strain was calculated in two eyes of two subjects, showing substantially different responses.
We demonstrated the feasibility of high-frequency ultrasound elastography for noninvasive in vivo measurement of the cornea's biomechanical responses to the intrinsic ocular pulse. The high intrasession and intersession repeatability suggested a robust implementation of this technique to the in vivo setting.
OPE may offer a useful tool for clinical biomechanical evaluation of the cornea by quantifying its response to the intrinsic pulsation.
本研究旨在建立一种使用高频超声弹性成像方法（即眼脉冲弹性成像（OPE））重复测量人眼心跳引起的角膜位移和应变的体内数据采集和处理方案。
本研究招募了 24 名无已知眼部疾病的志愿者。使用 PASCAL 动态轮廓眼压计（DCT）测量眼内压（IOP）和眼脉冲幅度（OPA）。开发了一种体内 OPE 方案来测量心跳引起的角膜位移。使用 50MHz 超声探头以每秒 128 帧的速度获取中央 5.7mm 角膜的视频。使用超声斑点跟踪算法分析 1000 帧的射频数据，以计算角膜位移并量化光谱和时间特征。还分析了 OPE 和 DCT 测量参数的日内和日间重复性。
体内 OPE 方案和设置成功地使用高频超声跟踪心跳引起的角膜运动。角膜轴向位移显示出强烈的心脏节律，具有良好的日内和日间重复性，以及高度的双眼对称性。在两名志愿者的两只眼中计算了角膜应变，显示出明显不同的反应。
我们证明了高频超声弹性成像在非侵入性体内测量角膜对固有眼脉冲的生物力学反应的可行性。高日内和日间重复性表明该技术在体内环境中的实施具有很强的稳健性。
杨玉莹
