New contact lens technology offers high-sensitivity, real-time intraocular pressure monitoring

Glaucoma is a leading cause of blindness among people who are unable to monitor and manage their intraocular pressure (IOP) daily. The current tools for IOP measurement are not portable, convenient, easily accessible, or capable of continuous (24/7) monitoring. These limitations in existing IOP devices are a major contributor to inadequate ocular health management in glaucoma patients. This mismanagement could result in severe and irreparable problems for patients.

This problem is particularly concerning, considering that one of the factors behind increased IOP is age. As the global population ages, such ocular complications are likely to become more common, especially in Japan, which faces one of the world's most severe population-aging crises. Therefore, prompt and proactive efforts to address the current limitations of ocular health monitoring are expected to benefit the nation significantly over the long run.

In a recent breakthrough, a team of researchers from Japan, led by Professor Takeo Miyake from the Graduate School of Information, Production and Systems, Waseda University, Japan, and including Te Xiao, Hanzhe Zhang, Taiki Takamatsu, and Assistant Professor Saman Azhari from Waseda University, along with Professor Kazuhiro Kimura and Assistant Professor Atsushige Ashimori from Yamaguchi University, Japan, has proposed an innovative design and integration of a thin film into a contact lens, enabling users to monitor their IOP in real time during everyday use. Their novel findings were made available online and published in the journal npj Flexible Electronics on January 13, 2026.

In this study, the researchers fabricated a resistive sensor based on a cracked PEDOT:PSS/PVA (PEDOT: Poly(3,4-ethylenedioxythiophene); PSS: Poly(styrenesulfonate); PVA: Polyvinyl alcohol) thin film that leverages a multilayer structure and the intrinsic properties of each layer to readily and effectively measure and monitor the IOP in real time. They notably combined the sensor with a 70 MHz double-loop gold antenna for high-precision and continuous IOP measurement.

Moreover, by using state-of-the-art parity-time-symmetric wireless technology, the team remarkably increased the device's sensitivity by a factor of 183, compared to conventional wireless sensing systems, making it suitable for everyday use by people who require IOP management.

Furthermore, both in vitro wireless IOP measurements of a porcine eye and in vivo wireless IOP measurements in rabbit eyes modified via microbead injection, obtained using the fabricated sensor lens, showed a strong linear correlation with corresponding measurements made using a commercial tonometer.

This research demonstrates how innovative, outside-the-box thinking facilitates the utilization of the properties of a well-known material such as PEDOT:PSS through a few simple yet innovative steps to tackle one of the key challenges in ocular health monitoring. Professor Miyake points out: "It is generally very challenging to fabricate a device on a contact lens due to the size limitations while maintaining user comfort. To address these limitations, we used microfabrication to fabricate an IOP sensor that fits well on the contact lens while maintaining flexibility and user comfort. Moreover, the use of parity-time symmetry allows for much higher sensitivity in wireless detection, making this work a major step towards the future of daily, real-time ocular health monitoring devices."

"Overall, our platform is promising for long-term, non-invasive IOP monitoring, thus making a significant contribution to the early diagnosis and treatment of glaucoma," concludes Professor Miyake.