Abstract
Digital whole slide imaging allows pathologists to view biopsy slides on a computer screen instead of under a traditional microscope. Digital viewing facilitates real-time monitoring of search behavior and pupil diameter during the diagnostic process. In particular, eye-tracking could provide a basis for objective evaluation of clinical competence during training or automated tools that alert pathologists to conditions that may result in diagnostic errors. Prior research has shown that pupil diameter is sensitive to cognitive load, arousal, and switches between exploration and exploitation of the environment. Different categories of lesions in breast biopsies, from benign to cancerous, pose different levels of challenge to pathologists as indicated by elevated diagnostic disagreement for precancer and early stage cancer. If pupil diameter was sensitive to perceived difficulty in diagnosing biopsies, perhaps eye-tracking could be used to identify biopsies that may benefit from a second opinion in an effort to reduce diagnostic error. We measured baseline-corrected (phasic) and raw pupil diameter (tonic) in 89 pathologists who each viewed and diagnosed 14 breast biopsy cases that cover the diagnostic spectrum. Pupil data were extracted from the beginning of each trial. After removing 106 trials with poor eye-tracking quality, 1,140 trials remained. We used multiple linear regression with robust standard error estimates to account for dependent observations within pathologists. We discovered a positive association between phasic dilation and subject-centered difficulty, on the one hand, and between tonic dilation and untransformed difficulty ratings on the other. When controlling for biopsy ID, only the tonic-difficulty relationship persisted. Results suggest that tonic dilation may indicate overall arousal differences between pathologists and could signal a need for additional training and experience. Phasic dilation is sensitive to intrinsic characteristics of biopsies that tend to elicit higher difficulty ratings and could prompt second opinions for difficult cases.