Research Progress of Subretinal Implant based on Electronic Stimulation

Subretinal prosthesis is one kind of retinal prosthesis, which means that a microimplant based on MEMS technology is inserted in the subretinal space to stimulate the optic nerve and elicit an electrical-evoked response on the cortical region. The subretinal implant is made up of extraocular part and intraocular part. As an important part, the latter consists of accessorial setting and stimulation chip that contains microphotodiode array (MPDA) and microelectrodes. The main body of the paper is made up of four parts. First, the significance of the retinal prosthesis is given out; second, fundamental on both in retinal physiology and retinal prosthesis theory are introduced simply. Then the key segment about the subretinal microimplant is presented in detail. The third segment discusses all of its design concept and the fabrication of MPDA which also consists of several parts: first is microscopic configuration, electric prototype schematic and chip image COMS. The second is detailed fabrication flow with several special materials and the situation of its dimension. The fourth segment presents challenge and outlook