Figure 3: Webcam eye-tracking methodology – data quality.
(a) Fixation-based heatmaps for testing accuracy for timepoints one and two. Data are aggregated per group. The color of the point cloud corresponds to the intensity of the subjects’ gaze (red=strong; blue=weak). (b) Accuracy is quantified and expressed in pixels. (c) Sample rate in Hz and mean gaze on screen time in % are shown as additional indicators for the data quality at t1 and t2, respectively. The red dotted line marks the cutoff for study inclusion. Participants with either a sample rate<20 Hz or a gaze on screen rate<70% were excluded in the preprocessing phase.