Ocular performance evaluation - how prolonged near work with virtual and real 3D image modifies our visual system

Real and virtual three-dimensional (3D) imaging has found useful applications across different areas of health sciences and with the current rapidly progressive development stage we can expect that the use of 3D imaging soon will be a part of a daily visual load for medical personnel. To better understand the possible impact of prolonged work with 3D content on eye accommodative response and pupil size we compared two 3D imaging techniques - volumetric display that is real voxel-based system and anaglyph technique that is virtual pixel-based system. We have investigated accommodative lag and pupil responses in 38 emmetropic young adult after prolonged visual task with volumetric 3D display (n = 19) and with anaglyph 3D technique (n = 19). All participants were asked to perform relative depth perception task organized in three sessions. Accommodative response and pupil size were measured simultaneously immediately after each 10 min long session by using eccentric photorefractor (binocularly with 50 Hz frequency). We found differences in an accommodative lag and pupil size between right and left eye for the group who performed visual task on anaglyph 3D. The mean difference of accommodative lag between the right and the left eye was 0.13 +/- 0.05 D (F-1,F-36 = 2.71, P = 0.10). Slight pupil size differences between the right and the left eye was observed (F-1,F-36 = 4.70, P = 0.04). For volumetric 3D group we did not find significant differences of accommodative lag and pupil size between both eyes. A weak negative correlation was observed between the pupil size and the accommodative lag (Spearman correlation coefficient rho = -0.20, P < 0.001; volumetric 3D rho = -0.21, P = 0.011; anaglyph 3D rho = 0.19, P = 0.019). It appears that prolonged near work with anaglyph 3D might cause unequal post-task accommodative response between both eyes that could force the visual system to the possible accommodation-vergence conflict. This suggest that the real 3D imaging would be more suitable for health care applications compared to virtual 3D.