PupEyes: An Interactive Python Library for Pupil Size and Eye Movement Data Processing

We present PupEyes, an open-source Python package for preprocessing and visualizing pupil size and eye movement data. Developed with current best practices in mind, PupEyes offers a comprehensive and reproducible pupil preprocessing pipeline, as well as interactive visualizations to facilitate data exploration and outlier detection. In addition to pupil size data, PupEyes supports interactive visualization of eye movement data, including scanpath animations, fixation density plots, and area-of-interest (AOI) maps. It also provides tools for manually drawing AOIs, assigning fixations to AOIs, and computing basic AOI-based metrics. Cleaned data are returned as pandas data frames, making them compatible with other data analysis and visualization packages within the Python ecosystem. PupEyes also features an intuitive Application Programming Interface (API) and detailed online tutorials (https://pupeyes.readthedocs.io/), making it accessible to users with varying levels of programming experience. Overall, PupEyes (1) ensures that pupil size data are preprocessed in a principled, transparent, and reproducible manner, (2) helps researchers better understand their data through interactive visualizations, and (3) enables flexible extensions for further analysis tailored to specific research goals. We believe PupEyes is a useful addition to the analysis workflow for pupil size and eye movement data.