Department of Electro-Optical Engineering, School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
J Neural Eng. 2022 Jun 6;19(3). doi: 10.1088/1741-2552/ac6f82.
. Retinal prostheses aim to restore some vision in retinitis pigmentosa and age-related macular degeneration blind patients. Many spatial and temporal aspects have been found to affect prosthetic vision. Our objective is to study the impact of the space-variant distance between the stimulating electrodes and the surface of the retina on prosthetic vision and how to mitigate this impact.. A prosthetic vision simulation was built to demonstrate the perceptual effects of the electroderetina distance (ERD) with different random spatial variations, such as size, brightness, shape, dropout, and spatial shifts. Three approaches for reducing the ERD effects are demonstrated: electrode grouping (quads), ERD-based input-image enhancement, and object scanning with and without phosphene persistence. A quantitative assessment for the first two approaches was done based on experiments with 20 subjects and three vision-based computational image similarity metrics.The effects of various ERDs on phosphenes' size, brightness, and shape were simulated. Quads, chosen according to the ERDs, effectively elicit phosphenes without exceeding the safe charge density limit, whereas single electrodes with large ERD cannot do so. Input-image enhancement reduced the ERD effects effectively. These two approaches significantly improved ERD-affected prosthetic vision according to the experiment and image similarity metrics. A further reduction of the ERD effects was achieved by scanning an object while moving the head.ERD has multiple effects on perception with retinal prostheses. One of them is vision loss caused by the incapability of electrodes with large ERD to evoke phosphenes. The three approaches presented in this study can be used separately or together to mitigate the impact of ERD. A consideration of our approaches in reducing the perceptual effects of the ERD may help improve the perception with current prosthetic technology and influence the design of future prostheses.
. 视网膜假体旨在为色素性视网膜炎和年龄相关性黄斑变性的盲人患者恢复部分视力。已经发现许多空间和时间方面会影响假体视觉。我们的目标是研究刺激电极与视网膜表面之间的空间变化电极-视网膜距离（ERD）对假体视觉的影响，以及如何减轻这种影响。建立了一种假体视觉模拟，以演示具有不同随机空间变化（例如大小、亮度、形状、缺失和空间移位）的 ERD 的感知效果。展示了三种减少 ERD 影响的方法：电极分组（四边形）、基于 ERD 的输入图像增强以及有/无闪光后效的物体扫描。根据 20 名受试者的实验和三种基于视觉的计算图像相似性度量标准，对前两种方法进行了定量评估。模拟了各种 ERD 对闪光大小、亮度和形状的影响。根据 ERD 选择的四边形有效地引出了闪光，而不会超过安全电荷密度限制，而具有大 ERD 的单个电极则不能这样做。输入图像增强有效地降低了 ERD 效应。根据实验和图像相似性度量标准，这两种方法显著改善了受 ERD 影响的假体视觉。通过在移动头部的同时扫描物体，进一步降低了 ERD 效应。ERD 对视网膜假体的感知有多种影响。其中之一是由于具有大 ERD 的电极无法引出闪光而导致的视力丧失。本研究提出的三种方法可以单独或组合使用来减轻 ERD 的影响。考虑我们在减轻 ERD 的感知影响方面的方法可能有助于改善当前假体技术的感知，并影响未来假体的设计。
