Opie Nicholas L, Ayton Lauren N, Apollo Nicholas V, Ganesan Kumaravelu, Guymer Robyn H, Luu Chi D
Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, The University of Melbourne, Melbourne, Victoria, Australia.
Artif Organs. 2014 Jun;38(6):E82-94. doi: 10.1111/aor.12287. Epub 2014 Apr 1.
Retinitis pigmentosa affects over 1.5 million people worldwide and is a leading cause of vision loss and blindness. While retinal prostheses have shown some success in restoring basic levels of vision, only generic, "one-size-fits-all" devices are currently being implanted. In this study, we used optical coherence tomography scans of the degenerated retina from 88 patients with retinitis pigmentosa to generate models of retinal thickness and curvature for the design of customized implants. We found the average retinal thickness at the fovea to be 152.9 ± 61.3 μm, increasing to a maximum retinal thickness of 250.9 ± 57.5 μm at a nasal eccentricity of 5°. These measures could be used to assist the development of custom-made penetrating electrodes to enhance and optimize epiretinal prostheses. From the retinal thickness measurements, we determined that the optimal length of penetrating electrodes to selectively stimulate retinal ganglion cell bodies and interneuron axons in the ganglion cell layer should be 30-100 μm, and to preferentially stimulate interneurons in the inner nuclear layer, electrodes should be 100-200 μm long. Electrodes greater than 200 μm long had the potential to penetrate through the retina into the choroid, which could cause devastating complications to the eye and should be avoided. The two- and three-dimensional models of retinal thickness developed in this study can be used to design patient-specific epiretinal implants that will help with safety and to optimize the efficacy of neuronal stimulation, ensuring the best functional performance of the device for patients.
视网膜色素变性影响着全球超过150万人，是视力丧失和失明的主要原因。虽然视网膜假体在恢复基本视力水平方面已取得一些成功，但目前植入的只是通用的“一刀切”设备。在本研究中，我们对88例视网膜色素变性患者退化的视网膜进行光学相干断层扫描，以生成视网膜厚度和曲率模型，用于定制植入物的设计。我们发现中央凹处的平均视网膜厚度为152.9±61.3μm，在鼻侧偏心度为5°时，视网膜最大厚度增加到250.9±57.5μm。这些测量结果可用于协助开发定制的穿透电极，以增强和优化视网膜外假体。根据视网膜厚度测量结果，我们确定选择性刺激神经节细胞层中的视网膜神经节细胞体和中间神经元轴突的穿透电极的最佳长度应为30-100μm，而优先刺激内核层中的中间神经元时，电极长度应为100-200μm。长度大于200μm的电极有可能穿透视网膜进入脉络膜，这可能会给眼睛带来毁灭性的并发症，应予以避免。本研究中建立的视网膜厚度二维和三维模型可用于设计针对患者的视网膜外植入物，这将有助于提高安全性并优化神经元刺激的效果，确保该设备为患者提供最佳功能表现。
