Microfluidic contact lens: fabrication approaches and applications

Microfluidic contact lenses integrate microscale features that can efficiently and precisely manipulate, interact, and analyze the small volumes of tears available in the limited accessible space for the lens in the eye. The microfluidic network on contact lenses allows the miniaturization of biochemical operations on the wealth of physiological information available in the eye. Sensors integrated into channels enable real-time monitoring of ocular parameters, including glucose, pH, electrolytes, or other biomarkers. Additionally, microchannel-integrated contact lenses have demonstrated potential as power-free, continuous intraocular pressure monitoring platforms for the effective management of glaucoma. Furthermore, the controlled release of medications directly onto the eye from microfluidic contact lenses enhances therapeutic efficacy by increasing bioavailability. Despite current challenges such as scalable fabrication techniques, microfluidic contact lenses hold immense promise for ocular health, bridging the gap between diagnostics and treatment. This review summarizes the progress made in the design and fabrication of microfluidic contact lenses, with a special emphasis on the methods adopted to fabricate microfluidic contact lenses. Furthermore, the various applications of microfluidic contact lenses, ocular disease diagnosis, and drug delivery in particular are discussed in detail. Aside from outlining the state-of-the-art research activities in this area, challenges and future directions are discussed here.