Effect of a vergence-accommodation conflict induced during a 30-minute Virtual Reality game on vergence-accommodation...

The aim of the study was to verify the hypotheses that vergence-accommodation conflict (VAC) induced with head-mounted device (HMD) could cause symptoms in relation to changes in the accommodative-vergence system. In order to test this hypothesis, the Virtual Reality (VR) exposures were carried out in two types of VAC: VAC_small and VAC_large.

Eighteen females, with a mean age of 22.5 ± 2.0 years, participated in two 30-minutes sessions with VR, which were separated by at least one week. Two sessions were differentiated by intensity of VAC presented in the VR system (VAC_small and VAC_large). Visual parameters were measured such as associated and dissociated phoria, accommodative response, the near point of convergence (NPC), fusional vergence ranges (FVR) and subjective complaints were measured using Simulator Sickness Questionnaire (SSQ). The parameters were measured immediately before (Pre-test) and after (Post-test) the VR exposure.

The subjective symptoms as nausea, oculomotor disorders and disorientation increased significantly after 30-minutes of exposure on VAC_large (P<0.05). The associated and dissociated phoria, lag of accommodation, FVR and the NPC did not significantly change after the VR exposure (P>0.05).

Short-term use of HMD (30-min) did not significantly affect accommodative-vergence functions regardless of the size of VAC (VAC_small and VAC_large). However, the level of symptoms increased after VR sessions, which was probably related to inappropriate oculo-vestibular relationship.