Arrowhead-Shaped Microelectrodes Fabricated on a Flexible Substrate for Enhancing the Spherical Conformity of Retinal Prostheses

In this paper, a novel microelectrode array (MEA), with varying arrowhead shapes, is fabricated and evaluated for retinal prostheses. The proposed MEA has a total of 199 arrowhead-shaped microelectrodes, with heights ranging from 42 to 123.5 μm. This height variation allows each microelectrode to contact the spherical eyeball conformably and to approach the stimulation target retinal cells very closely. The fabricated MEAs are implanted in rabbit eyes. The physical contact of the MEA is evaluated using optical coherent tomography (OCT) images, which show that the implanted MEA makes an excellent conformal contact with the spherically shaped retinal layers. These OCT images also exhibit good biocompatibility of the implanted MEA. The evaluation results show that the proposed MEA has a high potential for clinical applications. Our ongoing project is aimed at clinical application in three years. [2010-0037].