Retinal prosthetic devices currently under development are designed to bypass the non-functioning portion of the visual pathway (photoreceptor layer) in individuals suffering from diseases including retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Current devices enable patients to only see object positions and read large letters, and further technical advancements are required for improved vision and device safety. These advancements include high resolution neural interfacing, fully intraocular implantation, tack-free fixation of the electrodes in close proximit to the retina, and ultra-flexible, reliable packaging. This project will address each or these needs. This Small Business Technology Transfer Phase II project proposes development of Novel Ultra-Flexible Hybrid Circuits for Intraocular Retinal Prostheses. In these flexible retinal implants, ultra-thin silicon integrated circuits (IC's) will be electrically connected to a flexibl electrode array and thin-film antenna coil, then fully encapsulated between multiple layers of polymers resulting in a monolithic implantable neural interface. This implantable neural interface will consist of a microstimulator IC, an electrode array, a RF antenna, and high density connections between components. The polymer layers will serve not only as the device substrate but also as protection for the components from the corrosive effects of the biological fluids. The device will be pre-formed following the curvature of the eye and coupled with a superstructure so as to be under slight compression after implantation in the eye, helping to hold it secure and stabilize the electrodes against the surface of the retina. This will lead to a device with better visual acuity and to a safer retinal prosthesis without the use o a retinal tack and the need of a cable penetrating the eye wall.
Advancements in microfabrication and materials have made possible the development of miniaturized flexible neural interfaces. These medical devices are targeted at treating incurable neurological disorders. Such diseases are widespread in the population as a whole and their impact on individual health is profound. The progress made so far by us and many others in integrating miniaturized flexible circuits with microelectrode arrays and packaging solutions suitable for implant procedures demonstrates that our technology has the potential to lead to a successful commercialization of fully implantable wireless neural interfaces, an essential requirement for clinical systems. Medical devices like the retinal stimulator will make a real impact on public health by providing the neurosurgeon with entirely new sets of tools to deal with the many nervous system dysfunctions that afflict mankind.