Artificial Retina IC Jun Ohta 1 Introduction Artificial retina or, in general, artificial vision, is a prosthesis device to regain vi- sion for the blind. The similar sensory prosthesis device is an artificial cochrea, which has been successfully developed and widely used in many deaf patients in the worldwide to regain sound. Now in the world, a number of research and devel- opment onartificial reina [16] are progressing and will be produced commercially in near future. This chapter is organized as follows; First, fundamentals of artificial retina are presented. The structure of human eye and blindness are described in the section. Artificial retina devices are classified in terms of the implantation place of the de- vice. There are three types of artificial retina devices; ep-retina implantation, sub- retina implantation and supra-choroidal implantation. They are explained with some description of comparison among them. In the next section, basic circuits for arti- ficial retina devices are introduced. First, retinal stimulator circuits are mentioned. Requirements for safery operation in human body are addressed such as AC pow- ering and charge balancing. Then, photosensors which are improtant circuits for sub-retinal implanation are descirbed in details. In the last section, the case study of an artificial retina device is introduced. Before starting the first section, the terminology of reitnal prosthesis is briefly addressed. There are several terms for retinal proshteis; artificial vision, artificial sight, visual prosthesis, artificial retina and so on. As this chapter focuses on the stimulation of retina by CMOS technologies, an artificial retina is used. Jun Ohta Graduate School of Materials Science, Nara Institute of Science and Technology, e-mail: ohta@ms.naist.jp 1