Continuous monitoring of intraocular pressure, particularly during sleep, remains a grand challenge in glaucoma care. Here we introduce a class of smart soft contact lenses, enabling the continuous 24-hour monitoring of intraocular pressure, even during sleep. Uniquely, the smart soft contact lenses are built upon various commercial brands of soft contact lenses without altering their intrinsic properties such as lens power, biocompatibility, softness, transparency, wettability, oxygen transmissibility, and overnight wearability. We show that the smart soft contact lenses can seamlessly fit across different corneal curvatures and thicknesses in human eyes and therefore accurately measure absolute intraocular pressure under ambulatory conditions. We perform a comprehensive set of in vivo evaluations in rabbit, dog, and human eyes from normal to hypertension to confirm the superior measurement accuracy, within-subject repeatability, and user comfort of the smart soft contact lenses beyond current wearable ocular tonometers. We envision that the smart soft contact lenses will be effective in glaucoma care.

We present a sub-mm, fully wireless, implantable intraocular pressure monitor microsystem (IMM) that comprises a powering coil, an antenna, a piezoresistive micro-electro-mechanical system pressure sensor, and a pressure sensing IC. The system provides a 24-h intraocular pressure monitoring, which is not possible with currently used tonometric measurements. The IMM volume is limited to 0.38 mm (4 × smaller than previous state-of-the-art) for the studies on laboratory rodents prior to human use. A cavity resonator magnetic coupling delivers the wireless power to the chip with 4.89% efficiency. The chip senses a change in a differential sensor resistance by providing a low-power differential resistance to frequency conversion with the measured standard deviation in differential resistance sensing of . The data packets are wirelessly transmitted by an ultralow power 2.4-GHz ISM band OOK transmitter. The IMM is integrated on a 5-μm-thick biocompatible Parylene C substrate. Implemented in a 0.18-μm CMOS process, the system achieves 0.67-mmHg pressure sensitivity with differential resistance sensing and dissipates only 6.3 nW with 30 min of measurement intervals. We verify the IMM functionality in the in vivo biological experiment.

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