Sequential-Digital Image Correlation for Mapping Human Posterior Sclera and Optic Nerve Head Deformation
Sequential-Digital Image Correlation for Mapping Human Posterior Sclera and Optic Nerve Head Deformation
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DOI：
10.1115/1.4026224
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发表时间：
2014-02-01
影响因子：
1.7
通讯作者：
Vande Geest, Jonathan P.
中科院分区：
文献类型：
--
作者：
Pyne, Jeffrey D.;Genovese, Katia;Vande Geest, Jonathan P.
视神经乳头（ONH）变形可能与青光眼的发作或进一步发展有关，包括眼内压（IOP）相对正常的患者。表征生理压力下的后巩膜变形可以更好地理解IOP的变化如何导致ONH的机械环境的变化以及可能的视网膜神经节细胞死亡。压力膨胀测量测试协议通常用于通过全场非接触式光学方法测量视乳头周围巩膜的变形。这项工作的目的是开发和验证一种新的顺序3D数字图像相关（S-DIC）方法，用于量化后巩膜压力引起的变形，提高了DIC测量的z（深度）分辨率，而不会失去平面内的灵敏度，同时还能够轮廓和映射复杂形状的ONH的变形。我们的方法结合了两个正交轴的视差与标准的三维DIC方法，使用一个单一的高分辨率相机。S-DIC相对于标准3D DIC的增强功能已通过对已知复杂几何形状的物体进行形状、变形和应变测量的完整基准测试得到证明。我们的S-DIC方法提供了0.17%的重建精度和8 μ m的z位置测量的不确定性。所开发的方法也已应用于人类后巩膜壳，包括完整的视乳头周围巩膜和视神经。相对便宜的S-DIC方法可以提供关于视神经乳头的生物力学变形的新信息，因此，原发性开角型青光眼中视网膜神经节细胞的死亡。
Optic nerve head (ONH) deformations may be involved in the onset or further development of glaucoma, including in patients with relatively normal intraocular pressures (IOPs). Characterizing posterior scleral deformations over physiological pressures may provide a better understanding of how changes in IOP lead to changes in the mechanical environment of the ONH and possibly retinal ganglion cell death. Pressure inflation measurement test protocols are commonly used to measure deformation of the peripapillary sclera with full-field noncontact optical methods. The purpose of this work was to develop and validate a new sequential 3D digital image correlation (S-DIC) approach for quantification of posterior scleral pressure induced deformation that improves z (in-depth) resolution of the DIC measurement without losing in-plane sensitivity, while also being able to contour and map deformations of the complex-shaped ONH. Our approach combines two orthogonal axes of parallax with standard 3D DIC methods using a single high-resolution camera. The enhanced capabilities of S-DIC with respect to standard 3D DIC has been demonstrated by carrying out a complete benchmark for shape, deformation, and strain measurement on an object of known complex geometry. Our S-DIC method provided a reconstruction accuracy of 0.17% and an uncertainty in z-position measurement of 8 mu m. The developed methodology has also been applied to a human posterior scleral shell, including the full peripapillary sclera and optic nerve. The relatively inexpensive S-DIC approach may provide new information on the biomechanical deformations of the optic nerve head and, thus, the death of retinal ganglion cells in primary open angle glaucoma.