A virtual approach: Systematic review and meta-analysis of virtual reality-based therapies for convergence insufficiency

Convergence insufficiency (CI) is a common binocular vision disorder that significantly impacts visual comfort and quality of life. It has been hypothesized that CI therapy can also be provided effectively with Virtual reality (VR). Recently, a few studies were conducted on virtual reality-based CI therapy. However, to the best of the authors' knowledge, no systematic review and meta-analysis has been performed on the effectiveness of VR-based CI therapy. Therefore, this study aims to fill this critical gap and investigate the effectiveness of VR-based CI therapy. Consequently, it may be helpful to the clinicians, patients, and researchers to choose therapy, and develop future research studies. A systematic search was conducted on Google scholar, Scopus, PubMed and Science Direct until October 1, 2024. A total of 649 studies were screened, of which 3 studies were eligible to be included. We evaluated the quality and risk of bias for the included studies. Using the random-effects model, we found an overall mean difference of 3.38 (95% CI: 1.61, 5.16) before and after VR-based therapy. I² was 54.82% in our study, which indicates moderate heterogeneity. Then, we performed a Q test and found Q (df = 2) = 4.3593 and p-value = 0.1131, which indicates that albeit some heterogeneity observed in our analysis, it was not statistically significant. We also performed Leave-One-Out sensitivity analysis, which indicates that the overall findings of our analysis were relatively stable and not excessively dependent on any single selected study. No significant evidence of publication bias was found by using a funnel plot, Begg's test (Kendall's Tau = 1, p-value = 0.33), and Egger's test (intercept = 2.45, p-value = 0.40). Although we found VR based CI therapy has a positive effect, small sample size and variability in study methodologies make the current evidence insufficient to draw definitive conclusions regarding its effectiveness. Further studies are required to have more robust and reliable data.