title: Gaze entropy reflects surgical task load.
abstract: Task (over-)load imposed on surgeons is a main contributing factor to surgical errors. Recent research has shown that gaze metrics represent a valid and objective index to asses operator task load in non-surgical scenarios. Thus, gaze metrics have the potential to improve workplace safety by providing accurate measurements of task load variations. However, the direct relationship between gaze metrics and surgical task load has not been investigated yet. We studied the effects of surgical task complexity on the gaze metrics of surgical trainees.
  
  
  
  We recorded the eye movements of 18 surgical residents, using a mobile eye tracker system, during the performance of three high-fidelity virtual simulations of laparoscopic exercises of increasing complexity level: Clip Applying exercise, Cutting Big exercise, and Translocation of Objects exercise. We also measured performance accuracy and subjective rating of complexity.
  
  
  
  Gaze entropy and velocity linearly increased with increased task complexity: Visual exploration pattern became less stereotyped (i.e., more random) and faster during the more complex exercises. Residents performed better the Clip Applying exercise and the Cutting Big exercise than the Translocation of Objects exercise and their perceived task complexity differed accordingly.
  
  
  
  Our data show that gaze metrics are a valid and reliable surgical task load index. These findings have potential impacts to improve patient safety by providing accurate measurements of surgeon task (over-)load and might provide future indices to assess residents' learning curves, independently of expensive virtual simulators or time-consuming expert evaluation.
authors.affiliation: Neuroergonomics and Operator Performance Laboratory, University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain. distasi@ugr.es.|Mind, Brain, and Behavior Research Center (CIMCYC), University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain. distasi@ugr.es.|College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, USA. distasi@ugr.es.
authors.forename: Leandro L
authors.initials: LL
authors.lastname: Di Stasi
authors.affiliation: Neuroergonomics and Operator Performance Laboratory, University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain. dipie@ugr.es.|Mind, Brain, and Behavior Research Center (CIMCYC), University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain. dipie@ugr.es.|College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, USA. dipie@ugr.es.
authors.forename: Carolina
authors.initials: C
authors.lastname: Diaz-Piedra
authors.affiliation: Neuroergonomics and Operator Performance Laboratory, University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain.|Mind, Brain, and Behavior Research Center (CIMCYC), University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain.|Department of Signal Theory and Communications, University of Vigo, Vigo, Spain.
authors.forename: Héctor
authors.initials: H
authors.lastname: Rieiro
authors.affiliation: Line of Activity of the Andalusian Public Foundation for Progress and Health, Ministry of Equality, Health and Social Policy of the Regional Government of Andalusia, IAVANTE, Granada, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Sánchez Carrión
authors.affiliation: Line of Activity of the Andalusian Public Foundation for Progress and Health, Ministry of Equality, Health and Social Policy of the Regional Government of Andalusia, IAVANTE, Granada, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Martin Berrido
authors.affiliation: Line of Activity of the Andalusian Public Foundation for Progress and Health, Ministry of Equality, Health and Social Policy of the Regional Government of Andalusia, IAVANTE, Granada, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Olivares
authors.affiliation: Mind, Brain, and Behavior Research Center (CIMCYC), University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain.
authors.forename: Andrés
authors.initials: A
authors.lastname: Catena
mesh_terms: D000328:Adult; D003198:Computer Simulation; D019277:Entropy; D005133:Eye Movements; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D013502:General Surgery / Q000193:education; D006801:Humans; D007396:Internship and Residency; D008297:Male; D009784:Occupational Diseases / Q000503:physiopathology*; D015203:Reproducibility of Results; D013647:Task Performance and Analysis; D014940:Work Schedule Tolerance; D016526:Workload
keywords: Eye metrics; Neuroergonomics; Patient safety; Saccades; Surgical skills assessment