Figure 1: We propose GazeCast, a novel system that leverages users' personal hand-held mobile devices to enable gaze-based interaction with surrounding displays using Pursuits (A). In a user study, we evaluate GazeCast by experimenting with three tracking setups where participants' gaze was tracked: using a web camera (B), GazeCast with a mobile device attached to a stand (C), and GazeCast with a mobile device held by the participants (D). The illustration is adapted from GTmoPass by Khamis et al. [Khamis et al. 2017a].