Wireless intraocular pressure sensor using stretchable variable inductor

This paper reports the design, fabrication, and characterization of a wireless, flexible, passive pressure sensor that enables real-time intraocular pressure (IOP) monitoring. It employs a novel approach that measures the strain on the sclera of eye-ball using integrated planar stretchable variable inductor. Major reduction in fabrication complexity is achieved in contrast to the state-of-the-art solutions which are based on variable capacitors. Our device potentially improves the stability of long-term measurement by eliminating baseline drift due to leaks within sealed capacitive chambers. Implantation in the sclera reduces energy absorption by tissue, thereby improving inductive coupling efficiency between the implanted sensor and the external coil. This will significantly facilitate the commercialization of minimally invasive, in-vivo IOP sensing devices for Glaucoma patients. Devices are packaged using Parylene-C, which ensures the mechanical flexibility and biocompatibility of the sensor.