Flexible Parylene Packaged Intraocular Coil for Retinal Prostheses

We present a flexible and fully-implantable coil designed for use as a power and data transfer component in retinal prosthesis applications. Compared with traditional hand-made intraocular coils, this microfabricated coil is flexible, with a 9.5 mm outer diameter and 10-mum-thick parylene C as the primary structural and packaging material. A post-fabrication heat treatment was used to improve the parylene package in order to protect the device in harsh corrosive environments such as the human eye. Long-term accelerated-lifetime soak testing in heated saline has been performed, and the mean time to failure (MTTF) of the parylene package extrapolated to 37degC was estimated using the Arrhenius relationship. The electrical failure of this device was also characterized by measuring the DC resistance in saline