The influence of head-mounted displays on head and eye movements during visual search

This report describes an eye-tracking experiment which was conducted in the context of the student project Analyse und Modellierung von Blickbewegungen (Analysis and Modeling of Eye Movements) in summer term 2009 at Bielefeld University. The goal was to determine the influence of headmounted displays (HMDs) on natural visual search behavior. Subjects were instructed to find a previously specified number in a regular grid of numbers while their eye and head movements were tracked with an Eyelink II system. The task had to be accomplished under three different viewing conditions: full width of field of view, restriction of field of view via blinkers, and viewing through a Trivisio HMD. The recorded head and eye movements were used to calculate the eye-to-head movement coefficient for lateral fixations. Results show that wearing an HMD leads to less eye rotation and more head movement than under normal viewing conditions. Low resolution and a limited field of view seem to cause wearers of HMDs to adapt their natural lateral fixation behaviour. Those assumptions about eye rotation could be useful in future research projects focused on HMDs where direct access to actual eye data is not possible.