The Influence of Overminus Lens Therapy on Control of Intermittent Exotropia: A Meta-Analysis of Randomized Clinical Trials

BACKGROUND: Intermittent exotropia (IXT) is the most common type of strabismus, overminus lens (OML) therapy is frequently prescribed to treat IXT. OBJECTIVES: The purpose of this study was to compare the effectiveness of OML and observation in the treatment of IXT. METHOD: An exhaustive search of the literature in PubMed, Embase, Web of Science, and Cochrane Library databases was performed until July 2022. No language restrictions were used. The literature was rigorously screened according to eligibility criteria. Weighted mean differences and 95% confidence intervals (CIs) were calculated. RESULTS: A total of 4 articles with 561 participants were included in this meta-analysis. Our pooled results showed that OML demonstrated superior outcomes compared with observation, with greater decreases in distance and near exodeviation control (MD = −1.08, 95% CI: −1.96 to −0.20, p = 0.02; MD, −0.64, 95% CI: −1.15 to −0.13, p < 0.001). Patients who received OML therapy had a greater decrease in the deviation at both distance and near (MD = −4.00, 95% CI: −7.03 to −0.98, p < 0.001; MD = −4.79, 95% CI: −6.29 to −3.30, p < 0.001). There was no statistical difference between the two groups in terms of post-treatment proximal stereopsis (MD, 0.00, 95% CI: −0.08 to 0.08, p = 1.00). CONCLUSIONS: The present meta-analysis indicated that OML therapy was effective in improving the control and decreasing exodeviation angle of IXT. However, it seemed not to be effective in improving the level of near stereopsis.