Abstract
Purpose :
To innovate a novel flexible eyelid pressure sensor intricately integrated into contact lenses, aimed at spatially measuring eyelid pressure while ensuring conformal integration with the cornea, enhancing both accuracy and comfort.
Methods :
Utilizing kirigami design and microstructured ionic gel dielectrics, this study developed an iontronic pressure sensor array with 5 sensing channels. This sensor, aligned with corneal morphology, is embedded within a Piggyback-designed contact lens. Key attributes, including sensitivity, response time, and stability, were thoroughly characterized. A simulated anterior chamber was constructed, placing the sensor against the eyelid to evaluate the correlation between intraocular pressure and sensor readings under varying pressures induced by a custom-built micro-pump system. Animal experiments, including corneal reflex testing in conscious rabbits and multiple measurements under anesthesia, were conducted to assess reliability and repeatability. Pressure measurements in the central and peripheral eyelid regions were performed and benchmarked against commercial sensors. Comprehensive biocompatibility assessments were conducted, encompassing HE staining of rabbit eyes post 24-hour sensor application and MTT cell viability assays.
Results :
The sensor demonstrated ultra-high sensitivity (up to 237kPa−1, over 300 times greater than commercial ones) and an extremely short response time (60ms) at low pressures. It maintained mechanical stability over 6000 cycles at 10kPa and showed minimal capacitance change (less than 5%) over a wide intraocular pressure range (0-50mmHg). During corneal reflex-induced blinking, the sensor showed significant capacitance changes in the central 2mm area (approximately 2.35nF to 25.17nF). Compared to commercial sensors, which only provide an average pressure within a 6mm diameter, this sensor could distinctly measure pressures in the central and peripheral regions. Animal and cellular studies confirmed its biocompatibility.
Conclusions :
The newly developed eyelid pressure sensor could ultra-sensitively detect spatial eyelid pressure, due to integrating Kirigami artistry with cutting-edge iontronic technology. The conformal, smart, ultra-sensitive, and spatial features endow the eyelid pressure sensor with the ability to offer invaluable insights for understanding dry eye syndrome, orthokeratology, and eyelid surgeries.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.