Virtual reality head-mounted display game for intermittent exotropia in a randomized controlled trial

To evaluate the effects of orthoptic training using a virtual reality (VR) head-mounted display game in patients with intermittent exotropia (IXT), a prospective, randomized, double-blind study was performed in 62 patients ≥ 13 years with IXT of ≥ 8 prism diopters (∆) and with a near ≥ distance angle, i.e., basic type and convergence insufficiency-type IXT. Patients were randomly assigned to a video-game group that induced convergence (exercise group) and a placebo-game group not inducing convergence (control group), and completed the program 15 min/day for 4 weeks. Subjective symptom scores, angle of exodeviation, near point of convergence, stereoacuity, fusional control scores using the Newcastle Control Score (NCS) and the Office Control Score (OCS) were noted. Outcome measures were assessed after 4 weeks, and re-evaluated after a washout period of 4 weeks. After using the VR game for 4 weeks, the near angle of exodeviation significantly decreased from 29.6 ± 9.5∆ to 25.3 ± 9.0∆ in the exercise group (p < 0.001), which was still maintained after 4 weeks of discontinuation (p = 0.008). There were no significant differences in the near angle of exodeviation in the control group at either the 4- or 8-week visits (p = 0.075, 0.093, respectively). The fusional control scores of the NCS and OCS significantly improved at the 4-week (p = 0.001, 0.003, respectively) and 8-week visits (p = 0.004, < 0.001, respectively) only in the exercise group. In conclusion, orthoptic training using a VR game improved the near angle of exodeviation and fusional control scores in IXT.