Glaucoma remains a leading cause of irreversible blindness, particularly among patients who cannot regularly monitor and control intraocular pressure (IOP). However, existing IOP measurement tools are largely non-portable, inconvenient, and inaccessible for daily use. More importantly, they fail to support continuous, 24/7 monitoring, which is critical for effective disease management.
As a result, these limitations significantly contribute to poor ocular health outcomes in glaucoma patients. Inadequate monitoring can delay timely intervention, ultimately leading to severe and permanent vision loss.
Ageing Populations Intensify the Need for Better Solutions
This challenge becomes even more pressing when viewed through the lens of global ageing. Since increasing age is a known risk factor for elevated IOP, the prevalence of glaucoma-related complications is expected to rise steadily. Japan, in particular, faces one of the world’s most advanced population-ageing crises. Therefore, addressing gaps in ocular health monitoring now could deliver substantial long-term public health benefits.
A Contact Lens–Based Approach to Real-Time IOP Monitoring
Against this backdrop, researchers in Japan have introduced a promising new solution. A team led by Professor Takeo Miyake from the Graduate School of Information, Production and Systems at Waseda University has developed an innovative contact lens–based IOP monitoring system.
By integrating a thin-film sensor directly into a contact lens, the researchers enable users to measure their intraocular pressure in real time during everyday activities. The team reported these findings in the journal npj Flexible Electronics.
How the Thin-Film Sensor Measures IOP
In this study, the researchers fabricated a resistive sensor using a cracked PEDOT:PSS/PVA thin film. This material system—comprising Poly(3,4-ethylenedioxythiophene), Poly(styrenesulfonate), and Polyvinyl alcohol—leverages a multilayer structure and the intrinsic properties of each layer to deliver accurate and real-time IOP measurements.
To further enhance performance, the team integrated the sensor with a 70 MHz double-loop gold antenna. This design supports high-precision, continuous wireless monitoring without compromising comfort or flexibility.
Boosting Sensitivity Through Advanced Wireless Technology
Moreover, the researchers applied parity-time-symmetric wireless technology to dramatically improve detection performance. As a result, the device achieved a 183-fold increase in sensitivity compared to conventional wireless sensing systems, making it suitable for routine daily use by patients requiring regular IOP management.
Importantly, both in vitro tests on porcine eyes and in vivo experiments on rabbit eyes—where IOP was elevated using microbead injection—showed a strong linear correlation between readings from the sensor lens and those obtained using a commercial tonometer. This finding confirms the reliability and clinical relevance of the new system.
Implications for the Future of Glaucoma Care
Overall, this research highlights how innovative engineering can unlock new applications for well-established materials such as PEDOT:PSS. By combining microfabrication, flexible electronics, and advanced wireless techniques, the team successfully addressed one of the most persistent challenges in ocular health monitoring.
As reported by medicalxpress, Professor Miyake explains that fabricating devices on contact lenses is inherently difficult due to strict size constraints and the need to maintain user comfort. To overcome these barriers, the team employed microfabrication techniques to create a flexible sensor that fits seamlessly onto the lens.
He further notes that the use of parity-time symmetry significantly enhances wireless sensitivity, positioning this technology as a major step toward practical, real-time ocular monitoring. Ultimately, the platform shows strong promise for long-term, non-invasive IOP tracking and could play a vital role in the early diagnosis and timely treatment of glaucoma.