Non-invasive intraocular pressure monitoring system based on LC resonance

To ensure the real-time，accuracy and ease of operation of intraocular pressure (IOP) acquisition，a non-invasive flexible inductance capacitance (LC) intraocular pressure sensor with wearability was proposed based on the LC series resonance principle．The sensor adopted a preparation method of microchannel liquid metal injection based on soft lithography and thermoplastic molding，and the strain unit was an inductive coil made of liquid metal，which greatly improved the sensitivity of the sensor and wearing comfort． Meanwhile，a signal acquisition device dedicated to this intraocular pressure sensor was designed，including a swept signal generation circuit，an amplitude-phase detection circuit，a microcontroller control unit and a reading coil．Through the coupling of the reading coil and the intraocular pressure sensor，the amplitude-phase detection circuit was used to obtain the real maximum value of the equivalent impedance after coupling，so as to obtain the resonant frequency of the sensor．Experimental tests results show that the non-invasive IOP monitoring system achieves a sensitivity of 467.3 Hz/Pa，and the IOP measurement accuracy of the system is obtained to be ±0.2 kPa，which could satisfy the measurement requirements. © 2024 Huazhong University of Science and Technology. All rights reserved.