The three-dimensional (3D) mechanical response of the cornea to intraocular pressure (IOP) elevation has not been previously reported. In this study, we use an ultrasound speckle tracking technique to measure the 3D displacements and strains within the central 5.5[Formula: see text]mm of porcine corneas during the whole globe inflation. Inflation tests were performed on dextran-treated corneas (treated with a 10% dextran solution) and untreated corneas. The dextran-treated corneas showed an inflation response expected of a thin spherical shell, with through-thickness thinning and in-plane stretch, although the strain magnitudes exhibited a heterogeneous spatial distribution from the central to more peripheral cornea. The untreated eyes demonstrated a response consistent with swelling during experimentation, with through-thickness expansion overriding the inflation response. The average volume ratios obtained in both groups was near 1 confirming general incompressibility, but local regions of volume loss or expansion were observed. These results suggest that biomechanical measurements in 3D provide important new insight to understand the mechanical response of ocular tissues such as the cornea.

中文翻译：

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使用超声散斑跟踪对角膜变形进行 3D 表征

以前没有报道过角膜对眼压 (IOP) 升高的三维 (3D) 机械响应。在这项研究中，我们使用超声散斑跟踪技术来测量全球膨胀期间猪角膜中央 5.5[公式：见文本]mm 内的 3D 位移和应变。对经葡聚糖处理的角膜（用 10% 葡聚糖溶液处理）和未处理的角膜进行了膨胀测试。葡聚糖处理的角膜表现出预期的薄球形壳的膨胀响应，具有全厚度变薄和平面内拉伸，尽管应变幅度表现出从中央到更外围角膜的不均匀空间分布。未经治疗的眼睛在实验过程中表现出与肿胀一致的反应，厚度膨胀压倒通胀反应。在两组中获得的平均体积比接近 1，证实了一般不可压缩性，但观察到局部区域的体积损失或膨胀。这些结果表明，3D 中的生物力学测量为了解角膜等眼部组织的机械反应提供了重要的新见解。