<br/>Tear fluid has rich potential for diagnostics and personalized health monitoring. However, it remains largely inaccessible due to its small sample volume, and a lack of minimally invasive methods for accessing the ocular surface. Traditional methods for accessing tear fluid such as the Schirmer strip test, used in dry eye disease diagnosis, or extraction via a sterile pipette are invasive, irritating, and require a trained personnel. Furthermore, these methods can alter tear composition by inducing reflex tears, making the results from testing unreliable for diagnosis or health monitoring applications. In this work, we use commercial contact lenses as a platform for analyzing protein concentration in human tear fluid. By using a cost-effective and portable fluorescence well-plate reader that is integrated on a mobile-phone and a commercial enzymatic assay, we quantify lysozyme, a prevalent protein in tear fluid, after it is adsorbed non-specifically onto the contact lens surface during normal wear. Using this method we conducted a clinical study under IRB where a cohort of participants was monitored over a two week period to establish a baseline lysozyme concentration. We observed a statistically significant difference (p &lt; 0.05) in the participants’ baseline concentration when compared to a measurement performed after induced eye strain. Preliminary results also indicate a statistically significant difference in lysozyme concentration between the baseline established by the first cohort of participants and one-time measurements from a second cohort of participants, who were clinically diagnosed with dry eye disease. Taken together, these results show that contact lenses along with cost-effective and portable sensors have potential use for analyzing tear fluid for future diagnostics and personalized health monitoring applications.

Lysozyme sensing in tear using a contact lens

2019 Fall National Meeting

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