Magneto-elastic for wireless intraocular pressure monitoring

Increased intraocular pressure (IOP) can lead to optic nerve damage and various ocular diseases, including glaucoma, which is the primary cause of irreversible blindness. Thus, IOP monitoring is essential, but traditional tonometers are uncomfortable and inappropriate for continuous monitoring. Herein, we propose the combination of magneto-elastic sensing with smart contact lenses for IOP monitoring, offering the advantages of simple design, contactless detection, and low-frequency which is strong anti-interference. The Magneto-Elastic Sensor based IOP Monitoring System combines a magnetic contact lens (MCL) with a wireless signal reading circuit. When the MCL undergoes deformation in response to changes in IOP, this deformation affects the inductance value of the detecting coil, and the circuit collects data from the detecting coil to measure the variations in IOP. The MCL utilizes the commonly available and cost-effective Fe3O4 as the sensing layer. The sensing approach achieved a sensitivity of 0.114 nH/mmHg on an artificial rubber eye in vitro, while also demonstrating high resistance to interference from daily objects and the human body. Besides, this non-contact method allows for continuous, convenient, and comfortable monitoring of IOP. The system demonstrates the potential for integration into the metaverse and has shown high biocompatibility and comfortable wearability through testing.