A head mountable device for measuring eye movement includes: a frame a camera system comprising a first camera, wherein the camera system is coupled to the frame, and is configured to obtain a first set of images of a first eye of a user and a first liquid crystal display (LCD) shutter configured to control passage of light to the first eye based at least in part on a first control signal, the first LCD shutter is configured to operate in a first primary mode and a first secondary mode, wherein the first LCD shutter is configured to allow less light to reach the first eye in the first secondary mode than in the first primary mode.
