Observing eye-movement patterns in radiologists interpreting scans, researchers in Finland have shown that the eyes are—so to speak—a window into the soul of expertise and the level of experience.

The finding may suggest ways to improve resident training, the team reports in a small study posted ahead of print July 13 in Radiology.

Raymond Bertram, MS, PhD, and colleagues at Helsinki University Hospital and Turku University Central Hospital compared the visual behaviors of 15 early radiology residents (no more than 1.5 years of CT experience) with those of 14 advanced residents (1.5 to 3.5 years) and seasoned specialists (up to 22 years in abdominal radiology).

As the volunteer rads viewed 26 abdominal CT exams, the team recorded each participant’s eye movements with a desktop eye tracker, then analyzed the results with software applying linear mixed-effects models.

Bertram and colleagues found that the duration of eye fixation—the maintaining of gaze on a single location—increased with presentation speed in the specialists (β = .01) and advanced residents (β = .04) but not in the early residents (β = −.001).

When the participants viewed images with lesions, the team recorded shorter lengths of saccades—rapid eye movements occurring between two fixations—in the specialists than the residents.

This was telling because visual information is acquired only during fixations. Nothing can be taken in during saccades, the authors point out.

Further, adding yet more evidence to support the “experience counts” hypothesis, the team documented the early residents achieving lower lesion-detection rates toward the end of the day than toward the beginning.

This falloff in focus, sometimes called “vigilance decrement,” was not the case with the specialists or the advanced residents.

Commenting on this observation in their discussion, Bertram et al. suggest the radiology profession would do well to consider early residency as a kind of “hatching period.”

Early residents “are more likely to be affected by exhaustion than advanced residents and specialists, which should be taken into consideration when assigning their daily schedule,” they write.

“[O]ur results support the present inclination to abandon rigid time schedule-based resident training in exchange for a more individually tailored approach,” they add. “The analysis of development of expertise by eye-movement behavior could be useful to monitor individual residents’ learning curves and contribute to a further shift toward competency-based resident training.”