Background Non-strabismic binocular dysfunction can cause visual discomforts such as intermittent diplopia, blurriness, and asthenopia. This study investigates the impact of binocular dysfunction on cybersickness and postural control during Virtual Reality (VR) viewing, providing valuable insights for VR technology development. Methods A sample of 46 young adults (mean age 22.3 ± 1.98 years; 22 males and 24 females) was divided into a binocular dysfunction group (23 individuals) and a normal group (23 individuals) for comparative analysis. The binocular dysfunction group consisted entirely of individuals with exophoria, indicating a convergence-related fusional deficit rather than an accommodative problem. Participants underwent visual function assessments and completed the Ocular Visual Discomfort and Quality of Life (COVD-QOL) survey, and the Virtual Reality Sickness Questionnaire (VRSQ). Postural control was evaluated using the BtrackS balance plate. Results Results showed that the binocular dysfunction group exhibited significantly greater near exophoria, lower accommodative amplitudes, and reduced positive fusional vergence at both distance and near ( p < 0.05). They also reported higher visual discomfort (COVD-QOL, p < 0.05). After VR exposure, cybersickness significantly increased in both groups ( p < 0.001), with a greater rise in the binocular dysfunction group. This group also had higher oculomotor disorder and disorientation scores pre- and post-exposure. Postural instability significantly worsened after VR in the binocular dysfunction group ( p < 0.05), and cybersickness severity positively correlated with in-creased medial-lateral sway and sway ellipse area. In conclusion, binocular dysfunction exacerbates cybersickness and impairs postural control, representing a critical human factor in VR environments. These findings underscore the importance of developing optical technologies to mitigate the risks associated with binocular dysfunction, thereby enhancing user safety in VR.
박애진 et al. (Mon,) studied this question.