Psychomotor control in a virtual laparoscopic surgery training environment: gaze control parameters differentiate novices from experts

Abstract

BackgroundSurgical simulation is increasingly used to facilitate the adoption of technical skills during surgical training. This study sought to determine if gaze control parameters could differentiate between the visual control of experienced and novice operators performing an eye-hand coordination task on a virtual reality laparoscopic surgical simulator (LAP Mentor™). Typically adopted hand movement metrics reflect only one half of the eye-hand coordination relationship; therefore, little is known about how hand movements are guided and controlled by vision.MethodsA total of 14 right-handed surgeons were categorised as being either experienced (having led more than 70 laparoscopic procedures) or novice (having performed fewer than 10 procedures) operators. The eight experienced and six novice surgeons completed the eye-hand coordination task from the LAP Mentor basic skills package while wearing a gaze registration system. A variety of performance, movement, and gaze parameters were recorded and compared between groups.ResultsThe experienced surgeons completed the task significantly more quickly than the novices, but only the economy of movement of the left tool differentiated skill level from the LAP Mentor parameters. Gaze analyses revealed that experienced surgeons spent significantly more time fixating the target locations than novices, who split their time between focusing on the targets and tracking the tools.ConclusionThe findings of the study provide support for the utility of assessing strategic gaze behaviour to better understand the way in which surgeons utilise visual information to plan and control tool movements in a virtual reality laparoscopic environment. It is hoped that by better understanding the limitations of the psychomotor system, effective gaze training programs may be developed.

Gaze training improves the retention and transfer of laparoscopic technical skills in novices

“…Participants were fitted with an Applied Science Laboratories Mobile Eye gaze registration system (ASL, Bedford, MA), which uses dark pupil tracking to calculate gaze metrics [3,4]. The system consists of lightweight headgear that incorporates two cameras; one that records the participant's eye and the other the scene environment, and a trio of LEDs that project near-infrared (IR) light into the eye.…”

“…Visual gaze is computed using corneal reflection and the position of the center of the pupil, by comparing the vector between the pupil and cornea. Video streams from the two cameras are recorded at 30 Hz via a modified digital cassette recorder attached to a laptop installed with Eyevision (ASL) software [3,4].…”

“…The location of the relevant target was defined for each of the tasks as the trial unfolded: In the single hand learning task, the targets were the current ball in sequence and the cup; and in the two-handed transfer task, the targets were the red grasping area and blue cutting area of the filaments in sequence. Fixations were defined as gaze that remained on one of these locations (within 1°visual angle) for a minimum of 99.99 ms (C3 frames of video) [3,4,6,7]. The duration of all fixations on the target location and tool location was calculated for each attempt, and a target-locking measure computed by subtracting the percentage of tool fixation time from the percentage of target fixation time [3,4,6,7].…”

“…Recent research has revealed differences in the gaze control strategies of experienced and novice laparoscopic surgeons [3,4]. Novices, who are still developing the sensory-motor mapping rules for laparoscopy, use visual feedback to check on the effect of their movements, and so exhibit a gaze strategy that switches between tracking their tool movements and fixating the target to be manipulated (a switching strategy) [3,5]. Experienced surgeons, who have developed the necessary sensory-motor mapping rules, primarily fixate the target without the need to check their tool locations (a target-locking strategy) [3,4].…”

“…Novices, who are still developing the sensory-motor mapping rules for laparoscopy, use visual feedback to check on the effect of their movements, and so exhibit a gaze strategy that switches between tracking their tool movements and fixating the target to be manipulated (a switching strategy) [3,5]. Experienced surgeons, who have developed the necessary sensory-motor mapping rules, primarily fixate the target without the need to check their tool locations (a target-locking strategy) [3,4]. This more efficient gaze control strategy has been shown to underpin superior laparoscopic performance: Not only in cross sectional comparisons between experts and novices, but also in training studies.…”