Mechanical insult induced by intraocular pressure (IOP) is likely a driving force in the disease process of glaucoma. This study aimed to evaluate regional displacements in human optic nerve head (ONH) and peripapillary tissue (PPT) in response to acute IOP elevations, and their correlations with morphological characteristics of the posterior eye. Cross-sectional (2D) images of the ONH and PPT in 14 globes of 14 human donors were acquired with high-frequency ultrasound during whole globe inflation from 5 to 30 mm Hg. High-frequency ultrasound has a spatial resolution of tens of micrometers and is capable of imaging through the ONH and PPT thickness. Tissue displacements were calculated using a correlation-based speckle tracking algorithm for a dense matrix of kernels covering the 2D imaging plane. The ONH was manually segmented in the ultrasound B-mode images acquired at 5 mmHg based on echogenicity. The lamina cribrosa (LC) boundaries were visible in eight of the fourteen eyes and the LC region was segmented using a semi-automated superpixel-based method. The ONH had larger radial displacement than the PPT in all tested eyes and the difference increased with increasing IOP. A significant negative correlation was found between ONH-PPT displacement difference and PPT thickness (p < 0.05), while no significant correlations were found between ONH-PPT displacement difference and other morphological parameters including PPT radius of curvature, scleral canal size, LC thickness and anterior LC surface depth. Within the ONH, the radial displacement decreased in the region anterior to and across LC but not in the region posterior to LC. Finite element models using simplified geometry and material properties confirmed the role of LC in reducing the overall ONH radial displacements, but did not predict the displacement gradient change observed experimentally. These results suggested that a thinner PPT may be associated with a larger relative posterior motion of the ONH with respect to the surrounding PPT and the LC may play a major role in preventing excessive posterior displacement of ONH during acute IOP elevations.

眼内压（IOP）引起的机械损伤可能是青光眼疾病过程的驱动力。本研究旨在评估人类视神经乳头（ONH）和视乳头周围组织（PPT）响应急性眼压升高的区域位移，及其与后眼形态特征的相关性。在全球充气从 5 到 30 mm Hg 期间，通过高频超声采集了 14 名人类捐赠者的 14 个球体中 ONH 和 PPT 的横截面 (2D) 图像。高频超声具有数十微米的空间分辨率，能够透过ONH和PPT厚度进行成像。使用基于相关性的散斑跟踪算法计算覆盖 2D 成像平面的密集内核矩阵的组织位移。根据回声性，在 5 mmHg 下采集的超声 B 型图像中手动分割 ONH。十四只眼睛中的八只可以看到筛板 (LC) 边界，并且使用基于半自动超像素的方法对 LC 区域进行分割。在所有测试眼中，ONH 的径向位移均大于 PPT，且差异随着 IOP 的增加而增加。ONH-PPT 位移差与 PPT 厚度之间存在显着负相关（p < 0.05），而 ONH-PPT 位移差与其他形态参数（包括 PPT 曲率半径、巩膜管大小、LC 厚度和前 LC 表面深度。在 ONH 内，径向位移在 LC 前面和跨过 LC 的区域减少，但在 LC 后面的区域没有减少。使用简化的几何形状和材料特性的有限元模型证实了 LC 在减少整体 ONH 径向位移中的作用，但没有预测实验观察到的位移梯度变化。这些结果表明，较薄的 PPT 可能与 ONH 相对于周围 PPT 较大的相对后向运动有关，并且 LC 可能在防止急性 IOP 升高期间 ONH 过度向后移位方面发挥重要作用。