Retinitis pigmentosa (RP) and age related macular degeneration (AMD) affect 7.5 million people worldwide and are the leading causes of inherited and age-related blindness. Although new therapeutic strategies, such as gene therapy and stem cell therapy, etc., are emerging from intensive research, a retinal prosthesis offers a good treatment option for patients at the severe end-stage of RP or AMD. To improve the device performance and to provide patients with better functional vision, researchers are aiming for the next generation high-resolution retinal prostheses, which should solve current important questions and possess critical safety features. This article discusses some key design factors, such as selecting the implant locations, affixing the implant device, and designing the microelectrode array, etc. Several critical safety features, including charge density and charge balancing, power consumption and heat dissipation, voltage compliance monitoring and self-locking, backward data telemetry, etc., are discussed for consideration in the design of the next-generation devices. This review presents some ideas and inspirations for the relevant designers, doctors and patients.
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