New methods to measure information uptake and eye strain have been developed. The speed of information uptake is measured with a reading task that demands quick and accurate eyemovements. Accommodative facility is shown to be a good measure for eye strain. A standard monitor and three types of HMDs were compared on both tasks. The HMDs were (i) binocular and immersive, (ii) monocular and see-through, and (iii) monocular and see-around. These HMD types find applications in Virtual Environments, the cockpit, and Soldier Modernization respectively. Reading performance was measured while the subject was stationary and during head motion. From the experimental results rules of thumb for the use and design of HMDs are derived.