Nayagam David A X, Durmo Irfan, McGowan Ceara, Williams Richard A, Shepherd Robert K
Bionics Institute; Department of Pathology, The University of Melbourne;
Cochlear Limited.
J Vis Exp. 2015 Feb 14(96):52348. doi: 10.3791/52348.
Retinal prostheses for the treatment of certain forms of blindness are gaining traction in clinical trials around the world with commercial devices currently entering the market. In order to evaluate the safety of these devices, in preclinical studies, reliable techniques are needed. However, the hard metal components utilised in some retinal implants are not compatible with traditional histological processes, particularly in consideration for the delicate nature of the surrounding tissue. Here we describe techniques for assessing the health of the eye directly adjacent to a retinal implant secured epiretinally with a metal tack. Retinal prostheses feature electrode arrays in contact with eye tissue. The most commonly used location for implantation is the epiretinal location (posterior chamber of the eye), where the implant is secured to the retina with a metal tack that penetrates all the layers of the eye. Previous methods have not been able to assess the proximal ocular tissue with the tack in situ, due to the inability of traditional histological techniques to cut metal objects. Consequently, it has been difficult to assess localized damage, if present, caused by tack insertion. Therefore, we developed a technique for visualizing the tissue around a retinal tack and implant. We have modified an established technique, used for processing and visualizing hard bony tissue around a cochlear implant, for the soft delicate tissues of the eye. We orientated and embedded the fixed eye tissue, including the implant and retinal tack, in epoxy resin, to stabilise and protect the structure of the sample. Embedded samples were then ground, polished, stained, and imaged under various magnifications at incremental depths through the sample. This technique allowed the reliable assessment of eye tissue integrity and cytoarchitecture adjacent to the metal tack.
用于治疗某些形式失明的视网膜假体在世界各地的临床试验中越来越受到关注，目前商业设备已进入市场。为了评估这些设备的安全性，在临床前研究中，需要可靠的技术。然而，一些视网膜植入物中使用的硬质金属部件与传统的组织学方法不兼容，特别是考虑到周围组织的脆弱性质。在这里，我们描述了评估与用金属钉固定在视网膜表面的视网膜植入物直接相邻的眼部健康状况的技术。视网膜假体具有与眼组织接触的电极阵列。最常用的植入位置是视网膜表面位置（眼后房），植入物通过穿透眼球所有层的金属钉固定在视网膜上。由于传统组织学技术无法切割金属物体，以前的方法无法在金属钉原位的情况下评估近端眼部组织。因此，很难评估由钉插入引起的局部损伤（如果存在）。因此，我们开发了一种可视化视网膜钉和植入物周围组织的技术。我们对一种既定技术进行了改进，该技术用于处理和可视化耳蜗植入物周围的硬骨组织，以用于眼部的柔软脆弱组织。我们将固定的眼组织（包括植入物和视网膜钉）定向并嵌入环氧树脂中，以稳定和保护样品的结构。然后对嵌入的样品进行研磨、抛光、染色，并在不同放大倍数下对样品的不同深度进行成像。该技术能够可靠地评估与金属钉相邻的眼组织完整性和细胞结构。
