MEYELens: An affordable, open-source, 3D-printable eyewear platform for pupillometry and gaze tracking

Pupillometry and gaze tracking provide sensitive, noninvasive indices of autonomic function and cognitive state and are increasingly employed in neuroscience and clinical research. However, commonly used systems remain costly and often constrain hardware customization and workflow transparency. MEYELens is presented as an open-source, fully 3D-printable wearable system for low-cost pupillometry and gaze tracking using readily available components. The design is modular and mechanically adjustable to accommodate different users and experimental requirements. An open pipeline is provided for data acquisition and for both offline and online analysis. Feasibility is demonstrated across frequency-based and task-evoked pupillary paradigms, and gaze mapping is shown to operate in both screen-based and naturalistic settings. By combining affordability, modular hardware, and open software, MEYELens reduces barriers to reliable eye-based measurement and supports methodological development in resource-constrained research contexts.