Measurement of corneal biomechanical properties can aid in predicting corneal responses to diseases and surgeries. For delineation of spatially resolved distribution of corneal elasticity, high-resolution elastography system is required. In this study, we demonstrate a high-resolution elastography system using high-frequency ultrasound for ex-vivo measurement of intraocular pressure (IOP)-dependent corneal wave speed. Tone bursts of 500 Hz vibrations were generated on the corneal surface using an electromagnetic shaker. A 35-MHz single-element transducer was used to track the resulting anti-symmetrical Lamb wave in the cornea. We acquired spatially resolved wave speed images of the cornea at IOPs of 7, 11, 15, 18, 22, and 29 mmHg. The IOP dependence of corneal wave speed is apparent from these images. Statistical analysis of measured wave speed as a function of IOP revealed a linear relation between wave speed and IOP cs = 0.37 + 0.22 × IOP, with the coefficient of determination R2 = 0.86. We also observed depth-dependent variations of wave speed in the cornea, decreasing from anterior toward posterior. This depth dependence is more pronounced at higher IOP values. This study demonstrates the potential of high-frequency ultrasound elastography in the characterization of spatially resolved corneal biomechanical properties.

中文翻译：

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使用高频超声测量眼压相关的角膜弹性

角膜生物力学特性的测量有助于预测角膜对疾病和手术的反应。为了描绘角膜弹性的空间分辨分布，需要高分辨率弹性成像系统。在这项研究中，我们展示了一种高分辨率弹性成像系统，该系统使用高频超声进行眼内压 (IOP) 依赖性角膜波速的离体测量。使用电磁振动器在角膜表面产生 500 Hz 振动的音调脉冲。一个 35-MHz 的单元件换能器被用来跟踪角膜中产生的反对称兰姆波。我们在 7、11、15、18、22 和 29 mmHg 的 IOP 下获得了角膜的空间分辨波速图像。从这些图像中可以明显看出角膜波速的 IOP 依赖性。作为眼压函数的测量波速的统计分析揭示了波速和眼压之间的线性关系 cs = 0.37 + 0.22 × IOP，决定系数 R2 = 0.86。我们还观察到角膜中波速的深度依赖性变化，从前向后减小。这种深度依赖性在较高的 IOP 值下更为明显。这项研究证明了高频超声弹性成像在表征空间分辨角膜生物力学特性方面的潜力。