Recent advances in the study of tear biomarkers and contact lens-based biosensors

•The latest breakthroughs in tear biomarkers and their associated diseases were summarized.•Recent advances in contact lens-based biosensors for tear biomarkers detection were reviewed.•The advantages, limitations, limit of detection and detection ranges of contact lens-based biosensors were summarized.•Strategic insights for future research and expedite clinical translation of contact lens-based biosensors were provided. As an important body fluid, tears have shown great potential in point-of-care testing (POCT) because they contain abundant biomarkers associated with various diseases. However, conventional tear detection techniques, such as Schirmer strips, suffer from limited tear volume and disgusting tear collection process. In recent years, the development of contact lens-based wearable biosensors has offered a revolutionary, effective and real-time monitoring strategy for the detection of biomarkers in tears. Wearable contact lens-based biosensors can be used not only for the collection and detection of eye biomarkers but also for monitoring the changes of eye biomarkers, which is highly conducive to disease diagnosis and clinical management. In this work, we first summarized tear biomarkers relevant to diseases and highlighted contact lens biosensor advancements in colorimetric, optical and electrochemical detection. We also summarized the current state of the art and the potential strategies for the design and application of wearable contact lens-based biosensors. We expect that this work will contribute to the development of wearable contact lens biosensors.