Performance of a remote eye-tracker in measuring gaze during walking

Combining virtual environments and eyetracking can provide insights about the relationship between gaze and gait in people at high risk of fall. Remote eye-trackers can estimate gaze while the head moves within a limited workspace, but several factors can influence accuracy and precision. This study aimed at assessing the performance of a remote eyetracker both during controlled head movements and walking on a treadmill, while the visual stimulus moved on the screen. The head range of motion during gaze estimation was determined. The distance from the eye-tracker influenced data accuracy and precision of gaze estimation, while the target location was not a critical factor. The best accuracy was achieved at 650 mm from the eye-tracker (11±3 mm) and, during walking. Gaze fixations hitting static and moving objects were counted during standing (87 to 93 %) and walking (85 to 98 %), providing promising results for applications in virtual environments.