Eye tracking has evolved into a critical tool across multiple disciplines, from psychology and cognitive science to diagnostics and usability research. The recent Fundamentals of Eye Tracking series, published in Behavior Research Methods, provides a comprehensive guide to understanding, selecting, and implementing eye-tracking technology effectively. In our previous blog posts, experts in the field reflect on the manuscripts, offering valuable insights into the challenges and opportunities that come with using eye trackers in different research domains.

Do You Even Need an Eye Tracker?

Before diving into eye-tracking research, a fundamental question must be addressed: Do you actually need an eye tracker? Roy Hessels and Ignace Hooge emphasize that researchers should first determine whether eye tracking is the best method for their study. They outline key questions: Are you studying eye movements themselves, or using gaze as a proxy for something else? Is your study hypothesis-driven or exploratory? How strong is the link between eye movement data and the underlying theory? The discussion highlights that eye tracking should not be used simply for the sake of technology: its use must be justified by clear research and theory goals.

Choosing the Right Tools for Eye Tracking Research

Once researchers decide that eye tracking is necessary, the next challenge is selecting the right tools. Ellen Kok reflects on The Fundamentals of Eye Tracking Part 4, which provides an overview of available eye-tracking tools, and the problem domains researchers face. Many new researchers struggle with selecting software and hardware that match their needs, sometimes realizing too late that their chosen tools lack essential functionalities. While commercial eye-tracking software simplifies data collection and visualization, it often lacks the flexibility needed for complex experimental designs. Kok emphasizes that developing programming skills, or collaborating with those who have them, can significantly enhance a researcher’s ability to tailor tools to their specific needs.

Questioning the Assumptions Behind Eye Tracking

Denis Drieghe takes a critical look at the assumptions underpinning eye-tracking research. He reflects on how modern eye trackers have become highly user-friendly, often distancing researchers from the raw data and the complexities of eye movement measurements. This shift has made it more important than ever for researchers to understand the preprocessing decisions embedded in their software. Drieghe advocates for teaching students to examine eye-tracking data in its raw form to develop a deeper understanding of how fixations, saccades, and pupil size are processed into meaningful measures.

Both Drieghe and Kok emphasize the value of coding skills for eye-tracking research, as programming knowledge allows researchers to customize tools, analyze data more effectively, and avoid over-reliance on commercial software with built-in assumptions. Fortunately, Behavior Research Methods has published many articles on coding and data analysis tools, providing researchers with valuable resources to develop these skills. Understanding the mechanics of data processing not only improves methodological rigor but also empowers researchers to push the boundaries of what eye-tracking technology can achieve.

Eye Tracking in Clinical and Medical Applications

Beyond psychology and human behavior research, eye tracking is gaining traction in clinical settings. Dilce Tanriverdi and Frans Cornelissen explore its application in ophthalmology and neurology, particularly for diagnosing and monitoring visual impairments. Traditional clinical vision tests often rely on subjective patient responses, making them inconsistent. Eye tracking offers a more objective and automated alternative, improving diagnostic accuracy and enabling real-time monitoring of disease progression. However, selecting an eye tracker for clinical use comes with additional considerations, such as ease of calibration for diverse patient groups (especially children), compliance with regulatory standards, and integration with existing healthcare systems.

The Future of Eye Tracking

As eye-tracking technology advances, it continues to expand into new domains. The series of reflections on the Fundamentals of Eye Tracking highlights the importance of making informed methodological choices, whether for experimental psychology, clinical diagnostics, or applied research. Selecting the right eye tracker, questioning assumptions, and considering practical constraints are all essential steps toward conducting rigorous and impactful eye-tracking studies. The increasing accessibility of eye-tracking tools is both a blessing and a challenge. While modern systems make data collection easier, they also demand greater scrutiny in research design and analysis. As these reflections demonstrate, eye tracking is not just about recording where people look: it’s about understanding why and how they look, and what those insights mean for different scientific, theoretical, and practical applications.

Featured Psychonomic Society articles

Hessels, R.S., Nuthmann, A., Nyström, M., Andersson, R., Niehorster, D. C., Hooge, I. T. C. (2025). The fundamentals of eye tracking part 1: The link between theory and research question. Behav Res 57, 16. https://doi.org/10.3758/s13428-024-02544-8

Hooge, I.T.C., Nuthmann, A., Nyström, M., Niehorster, D. C., Holleman, G. A., Andersson, R., & Hessels, R. S. (2025). The fundamentals of eye tracking part 2: From research question to operationalization. Behav Res 57, 73. https://doi.org/10.3758/s13428-024-02590-2

Nyström, M., Hooge, I.T.C., Hessels, R.S., Andersson, R., Witzner Hansen, D., Johansson, R., & Niehorster, D. C. (2025) The fundamentals of eye tracking part 3: How to choose an eye tracker. Behav Res 57, 67. https://doi.org/10.3758/s13428-024-02587-x

Niehorster, D.C., Nyström, M., Hessels, R.S., Andersson, R., Benjamins, J. S., Witzner Hansen, D., & Hooge, I. T. C. (2025). The fundamentals of eye tracking part 4: Tools for conducting an eye tracking study. Behav Res 57, 46. https://doi.org/10.3758/s13428-024-02529-7