Abstract
Purpose :
To determine the effect of viewing virtual stereoscopic displays upon clinical measures of binocular function, including clinical measures of the accommodation and vergence crosslink interactions.
Methods :
26 subjects (mean age ± SD = 21.2±1.6 years) participated with informed consent. Subjects viewed a stereoscopic stimulus (86% contrast Maltese cross) created using a 3D LCD monitor (Zalman, ZM215W 21.5” 1920x1080), for 30 minutes. The stimulus was viewed at 40cm creating a fixed accommodation stimulus of 2.50D. The vergence stimulus varied sinusoidally at a frequency of 0.25 Hz, from 1.63 to 2.50 MA. A battery of clinical tests (stimulus gradient AC/A and CA/C ratios, visual acuity, horizontal heterophoria and positive and negative fusional reserves measured at distance and near, accommodation and vergence facility) were carried out in a randomised order prior to and immediately post exposure to the stereoscopic stimulus.
Results :
A significant increase was found in the group mean stimulus AC/A ratios following stereoscopic viewing (p<0.05), ranging from a 29% decrease to a 193% increase. Changes in the stimulus AC/A ratio were not correlated with the baseline AC/A ratio. Positive fusional reserve break and recovery point were significantly reduced at distance following stereoscopic viewing (p<0.01 for break and recovery) and a significant linear relationship was found between the baseline distance positive break point and the change in the distance positive break point following stereoscopic viewing (linear regression; R2=0.62, F(1,25) = 38.46, p<0.001). No significant change was demonstrated in stimulus CA/C group mean data following stereoscopic viewing. Visual acuity, accommodation and vergence facility were unaffected by stereoscopic viewing.
Conclusions :
Stereoscopic displays cause changes in the stimulus AC/A ratio which can be detected using clinical methods. Stimulus AC/A ratio and Fusional reserves at distance appear to offer the best clinical indicators of the effect of stereoscopic displays on the binocular vision system. These results suggest that stress on the binocular system could be the cause of asthenopia experienced during stereoscopic viewing.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.