Implantable micro-transceiver wireless link for intra-ocular pressure measurement

In the present work, the design and fabrication of a wireless capacitive pressure sensor is discussed. The sensor allows for the continuous measurement of intraocular pressure for glaucoma monitoring. The implanted microelectromechanical systems (MEMS) device has a novel in-house LC tank structure in which post assembly and wafer bounding is not required. Pressure variations in the eye, induce the deflection of a thin diaphragm and hence a change in capacitance and resonant frequency of the device. Using inductive coupling, an external coil records the pressure changes. Several sensors for a footprint area of 5 mm x 5 mm have been fabricated. In order to optimize the wireless link between the implantable device and the transmit antenna, the interactions with the electromagnetic waves through layered biological tissue are studied. A methodology for correlating the measured data to pressure is discussed.