An eye tracking apparatus includes a first image detector for capturing scene images, a second image detector fixed relative to the first image detector for capturing eye images including a pupil of a person and a reference object located within an image detection field, a processor for receiving the scene images and the eye images and outputting eye tracking images, each of the eye tracking images including a gaze point corresponding to a line of sight of the person, the processor for determining a location of the gaze point based on a calibration mapping that maps pupil location within the image detection field to the scene images and a correction mapping that corrects for movement of the reference object within the image detection field of the second image detector. Wherein the first image detector and the second image detector are coupled to a wearable accessory and movement of the reference object within the image detection field corresponds to movement of the wearable accessory relative to the person.