Eye Tracking: The First Half

In 1879, a Parisian ophthalmologist named Louis Émile Javal made some groundbreaking observations about eye movement and the way readers scanned across a series of words. After studying the eye movements of readers without the aid of eye tracking technology, he observed that humans’ eyes do not move continuously across a line of text, but make short rapid movements combined with short, momentary stops. These are the saccades and fixations we referred to in a recent Eye Tracking Update post. Javal was the first to report the lack of fluidity in eye movement and essentially kicked off the study of eye tracking.

Of course, eye tracking today is a wide-open field, with designers and engineers creating new technologies each day to help us further understand how the eyes move. As we know, eye tracking technology is used in advertisements, design studies, medical research and social communication. But as this article we came across points out, eye tracking has been around for a while.

Not long after Javal’s influential experiments, a man named Edmund Huey created an early eye tracking device using a sort of contact lens with a hole in the middle. The lens had a very thin aluminum pointer that moved where the eye moved, pointing to what the individual was looking at. Actually, the pointer traced and recorded the movement of the eye by displacing a dot of soot on a cylindrical paper drum. While quite ingenious, the device would be considered incredibly intrusive by today’s (and any) standards, and apparently he tried to alleviate any discomfort by his patients with desensitizing agents (the article states that at times, this even included cocaine!). Huey describes the device in detail in his influential publication The Psychology and Pedagogy of Reading in the early 20th century.

Eye tracking technology eventually grew to be a bit more sophisticated, and a non-intrusive eye tracking device was created by Charles H. Judd, a Ph.D. in psychology. Judd would develop an eye movement camera that took motion pictures that could be studied in detail by observing each individual frame. Using stop motion observation, Judd performed some of the original studies of eye movements in reading, linking his findings with reading efficiency and comprehension.

Judd worked closely with a man named Guy T. Buswell, a pioneer in experimental educational psychology. Buswell used Judd’s eye movement camera, analyzing the eye movements as a function of age and school grade level. Buswell found variations in fixations and saccades that change with age and learning, and his observations would lead to advancements in the field of education and literacy.

This brings us up to the early part of the 20th century. As you know, there’s plenty more that brought eye tracking from there to here, and we’ll catch up with the rest in the next post. Stay tuned….

A Brief History of Eye-Tracking

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