Objective To compare changes in ocular parameters after watching a display of three-dimensional (3D) images, with reference to motion-in-depth and viewer age.

Methods A total of 30 healthy subjects were enrolled (of whom 17 were aged 20–30 years and 13, 40–50 years). All subjects watched 3D displays with binocular disparities of 1° or 3° run towards the viewer (who wore polarised glasses) at two defined velocities (slow, 105 mm/s; fast, 257 mm/s) for 15 min at intervals of 1 week. The viewing distance was 1.020 m. The near point of accommodation (NPA) and near point of convergence (NPC), and the tear break-up time (tBUT) of each subject, were measured before and after watching the 3D display. All parameters were repeatedly measured at intervals of 10 min after watching until baseline values became re-established.

Results NPA and NPC deteriorated more, and tBUT decreased more, after watching a 3D display with fast rather than slow motion-in-depth (all p values <0.05). NPA deteriorated more in those aged 40–50 years as compared in those aged 20–30 years after watching a display of binocular disparity of 3° at fast motion-in-depth (p=0.028). NPC deteriorated more in those aged 40–50 years as compared in those aged 20–30 years after watching a display of binocular disparity of 3° at slow and fast motion-in-depth (p=0.001). The NPA and NPC recovery times were longer after watching at fast motion-in-depth than slow motion-in-depth (p<0.05). The decrease of tBUT was greater after watching at fast rather than slow motion-in-depth but only when the binocular disparity was 1°. All parameters returned to baseline values within 80 min.

Conclusions Motion-in-depth has an important influence on ocular parameters when a 3D display is watched, and our information would provide some basis in manufacturing 3D equipment.