Effects of a head-mounted display on the oculomotor system of children.

PURPOSE: This study evaluated the effects of short term and extended viewing of virtual imagery using the Binocular Viewer (new generation bi-ocular viewer) on the visual system of children, and compared these effects with that of viewing a high definition television (HDTV) display. METHODS: Sixty children aged 5 to 16 years viewed 30 min of virtual imagery using the Binocular Viewer and a HDTV display on two occasions. Sixteen subjects, aged 13 to 16 years, completed a third session of extended viewing (80 min) with the Binocular Viewer. Oculomotor function and symptoms were assessed previewing, immediately postviewing, and 10 min postviewing. RESULTS: Thirty minutes of Binocular Viewer use resulted in symptom increases (p < 0.05) immediately postviewing ("feeling tired," "feeling sleepy," "difficulty concentrating," and "sore/aching eyes") however most symptoms had dissipated by 10-min postviewing. There were no significant symptom differences between viewing with the Binocular Viewer and the HDTV display at either time point. An increase in symptoms (p < 0.05) immediately postviewing was recorded after 80 min of Binocular Viewer use ("feeling tired," "feeling bored," "feeling sleepy," and "tired eyes"), however only "feeling tired" and "feeling bored" remained significantly increased (p < 0.05) 10-min postviewing. Near unaided visual acuity demonstrated a significant and consistent reduction immediately (p < 0.01) and at 10 min (p < 0.05) following 30 min of Binocular Viewer use and immediately following 80 min of use (p < 0.01). Near unaided VA was also significantly reduced (p < 0.01) immediately after 30 min of HDTV display use. CONCLUSIONS: Virtual imagery viewing with the Binocular Viewer in children aged 5 to 16 years had few additional adverse effects when compared to viewing a more conventional HDTV display. The Binocular Viewer was comfortable to wear for up to 80 min of viewing. The consistent reduction in near vision for both viewing durations with the Binocular Viewer requires further investigation.