Age-related macular degeneration (AMD) and retinitis Pigmentosa (RP) are commonouter retinal degenerative Problems, and alsothe Predominant causesof most blinding retinal diseases. Retinal Prosthesis is a Promising solution for such PhotorecePtor degeneration diseases. Mostof current concePts for a retinal Prosthesis are basedon neuronal electrical stimulation. Inthe Pasttwenty years, retinal Prosthesis has been develoPed intwo different directions: ePiretinal Prosthesis and subretinal Prosthesis. Each Prosthesistechnique has its advantages and disadvantages. For ePiretinal Prosthesis, it is easierto be imPlanted and hasthe advantageof keePing mostofthe electronics inthe vitreous cavityoffthe retinal surface, which greatly helPs in dissiPatingthe heat generated bythe imPlant device. Inthis PaPer, a briefoverviewof retinal Prostheses concePts is introduced. Afterthat, several imPortant asPectsof ePiretinal electrical stimulation will be discussed. Moreover, some Practical ePiretinal Prosthesis devices develoPed by researchers in United States, Germany and JaPan inthe Past have been reviewed. We hoPethatthe devices will be used widely inthe near future.