High-sensitive microfluidic contact lens sensor for intraocular pressure visualized monitoring

Intraocular pressure (IOP) is the primary pathogenic indicator of glaucoma. Real-time IOP monitoring is significant for preventing, diagnosing, and treating glaucoma. Compared with contact lens sensors based on electronic components and photonic crystals, microfluidic contact lens sensors have the merits of good flexibility, straightforward IOP reading, and low cost. We report a high-sensitivity microfluidic contact lens sensor for direct IOP visual reading based on the bilateral wall structure. The bilateral wall structure substantially enhances the sensitivity and the linearity of the sensor. The dyed fish oil with good hydrophilicity, low viscosity, and almost non-volatile is selected as the liquid indicator. An automatic image processing program is designed to obtain the displacement of the liquid interface. The sensor exhibits a high sensitivity of 660 µm/mmHg and a linear regression coefficient of 0.999 in the operating range of 10–30 mmHg. The sensor steadily responds to IOP changes after 24 h of the static test and maintains high synchronization with pressure in multiple cycles at a pressure change rate of 3 mmHg/s. With high sensitivity, linearity, and sufficient flexibility, the sensor holds excellent potential for clinic application of IOP monitoring.