Publications by authors named "Geoffrey Tien"

During a laparoscopic operation, the surgical team should have a common understanding of the action plan which can be aided by focusing on the same surgical site. We show how measuring the overlap between two spatially and temporally aligned gaze recordings can be used to identify periods during which the primary operator and assistant were focused on different areas of the surgical display.

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Task-evoked pupil response (TEPR) has been extensively studied and well proven to be sensitive to mental workload changes. We aimed to explore how TEPR reflects mental workload changes in a surgical environment. We conducted a simulated surgical task that has 3 different subtasks with different levels of motor precision and different mental workload requirements.

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Blinks are related to several emotional states, and the present report describes a simple, reliable way to measure blinks from the video stream of an eye obtained during eyetracking, where the source of the eye video is a video camera attached to a head-mounted eyetracker. Computer vision techniques are employed to determine the moments that a blink starts and ends, for the purpose of calculating blink frequency and duration. The video is first processed to show blocks of eyelid and pupil movements, and is then analyzed for blink starts and ends.

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Introduction: Eye-gaze technology can be used to track the gaze of surgeons on the surgical monitor. We examine the gaze of surgeons performing a task in the operating room and later watching the operative video in a lab. We also examined gaze of video watching by surgical residents.

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Recording eye motions in surgical environments is challenging. This study describes the authors' experiences with performing eye-tracking for improving surgery training, both in the laboratory and in the operating room (OR). Three different eye-trackers were used, each with different capabilities and requirements.

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Background: Blinks are known as an indicator of visual attention and mental stress. In this study, surgeons' mental workload was evaluated utilizing a paper assessment instrument (National Aeronautics and Space Administration Task Load Index, NASA TLX) and by examining their eye blinks. Correlation between these two assessments was reported.

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Objective: Surgeons' vigilance regarding patient condition was assessed using eye-tracking techniques during a simulated laparoscopic procedure.

Methods: Surgeons were required to perform a partial cholecystectomy in a virtual reality trainer (SurgicalSim; METI Inc, Sarasota, FL) while wearing a lightweight head-mounted eye-tracker (Locarna systems Inc, Victoria, British Columbia, Canada). Half of the patients were preprogrammed to present a mildly unstable cardiac condition during the procedure.

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The vigilance of surgeons while operating is an important consideration for patient safety. Using a lightweight mobile eyegaze tracker, we can objectively observe and quantify a surgeon's vigilance measured as the frequency and duration of time spent gazing at an anaesthesia monitor displaying various patient vital signs. Expert surgeons and training surgical residents had their eyegaze recorded while performing a mock partial cholecystectomy on a computer simulator.

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In current radiologists' workstations, a scroll mouse is typically used as the primary input device for navigating image slices and conducting operations on an image. Radiological analysis and diagnosis rely on careful observation and annotation of medical images. During analysis of 3D MRI and CT volumes, thousands of mouse clicks are performed everyday, which can cause wrist fatigue.

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