ABSTRACT
This chapter focuses on the central piece of equipment, the eye tracker, and the physical and social space of the eye-tracking lab. Electrooculography is often used in sleep research because it does not require the participant to have her eyes open during recording. Video-based eye tracking has also become more affordable since it first became available in the mid-1970s. The principle behind video-based eye trackers is to detect one or more landmarks on the eye and infer the point of gaze using geometrical principles. Purkinje images are the reflections of objects from the curvatures of the eyes. Static eye trackers are appropriate for laboratory research, broadly construed as any study that can be conducted inside a research lab. Head-mounted eye trackers are worn in close proximity to the head, because they are attached to a headband or a cap, which further increases the flexibility of their use.
