A Three-Dimensional Microelectrode Array to Generate Virtual Electrodes for Epiretinal Prosthesis Based on a Modeling Study

• Published in: International journal of neural systems Vol. 30; no. 3; p. 2050006
• Main Authors: Lyu, Qing, Lu, Zhuofan, Li, Heng, Qiu, Shirong, Guo, Jiahui, Sui, Xiaohong, Sun, Pengcheng, Li, Liming, Chai, Xinyu, Lovell, Nigel H
• Format: Journal Article
• Language: English
• Published: Singapore 01.03.2020
• Subjects: Virtual electrode; electrical stimulation; microelectrode array; epiretinal prosthesis
• ISSN: 1793-6462
• DOI: 10.1142/S0129065720500069

Despite many advances in the development of retinal prostheses, clinical reports show that current retinal prosthesis subjects can only perceive prosthetic vision with poor visual acuity. A possible approach for improving visual acuity is to produce virtual electrodes (VEs) through electric field modulation. Generating controllable and localized VEs is a crucial factor in effectively improving the perceptive resolution of the retinal prostheses. In this paper, we aimed to design a microelectrode array (MEA) that can produce converged and controllable VEs by current steering stimulation strategies. Through computational modeling, we designed a three-dimensional concentric ring-disc MEA and evaluated its performance with different stimulation strategies. Our simulation results showed that electrode-retina distance (ERD) and inter-electrode distance (IED) can dramatically affect the distribution of electric field. Also the converged VEs could be produced when the parameters of the three-dimensional MEA were appropriately set. VE sites can be controlled by manipulating the proportion of current on each adjacent electrode in a current steering group (CSG). In addition, spatial localization of electrical stimulation can be greatly improved under quasi-monopolar (QMP) stimulation. This study may provide support for future application of VEs in epiretinal prosthesis for potentially increasing the visual acuity of prosthetic vision.