Identification of Tear-Based Protein Biomarkers: Its Application

Tears are a rich source of biomarkers in the form of proteins and peptides whose concentration changes could allow disease detection. The advancements in proteomics and detection methods have facilitated extensive exploration of tear proteins. This chapter introduces the basic anatomy and physiology of the tear film. This chapter discusses tear-based protein biomarkers for some of the most prevalent diseases with evidence on the direction of changes in concentrations reported in the literature thus far. A holistic solution from sampling tears to detecting diseases with high specificity in a point-of-care form factor is becoming attainable. The challenges remain regarding the lack of global standardization of the qualitative and quantitative methods and alternative methods of tear sampling that could be more user-friendly and reproducible. A summary of the techniques and approaches for biomarker discovery and practical methods toward user-friendly tear sampling are discussed.