Electronics-Free Visual Monitoring of Dry Eye Disease-Related Tear Biomarkers Using Smart Scleral Lenses.

Dry eye disease (DED) is a prevalent ocular condition characterized by tear film instability, hyperosmolarity, inflammation, and neurosensory abnormalities. Its episodic and fluctuating nature complicates diagnosis and management, as conventional clinical assessments often fail to capture transient tear film changes. Although emerging tear-sensing technologies show promise, many rely on trained personnel, only sporadic measurements, external readers, or integrated electronics, limiting their practicality for in-eye applications. Here, we present an electronics-free scleral lens platform for wearable monitoring of DED-related tear biomarker changes using passive colorimetric sensors integrated within the lens tear reservoir. This configuration enables visual and smartphone-assisted readout of chloride ions, pH, and ocular surface temperature within physiologically relevant ranges while avoiding direct contact with the corneal surface. The vaulted scleral lens geometry forms a stable, self-replenishing tear reservoir that concentrates biomarkers while shielding sensors from corneal contact and eyelid pressure. Sensor color changes are directly observable and quantifiable via a smartphone without specialized readers or user-specific calibration. Validated using artificial tear fluids, human tear samples, and in vivo models, this platform enables wearable monitoring of DED-related biomarkers within physiologically relevant ranges, offering a simple and clinically viable approach for tracking ocular surface conditions and associated treatment efficacy.