The effect of convergence insufficiency treatment on reading performance in school age children – A meta-analysis

Abstract

Introduction/purpose: Convergence insufficiency (CI) is a binocular vision disorder characterised by difficulty maintaining convergence and fixation at near. Depending on the severity of the CI, patients can present with a variety of symptoms during near vision tasks. Some studies indicate an increased incidence of CI in children with reading difficulties. Although a lot of research has been done on the effects of CI-treatments on eye-related symptoms, not much is known about its effect on performance related symptoms such as reading difficulties. The purpose of this meta-analysis is to determine if CI-treatments have a positive effect on reading performance. Methods: A search string was created to gather all relevant clinical trials on the National Centre for Biotechnology Information (NCBI) and Cochrane libraries. Only clinical trials were included that provided pre- and post treatment data on the effect of CI-treatment on reading performance in school aged children (5-18y). A total of three relevant clinical trials were found that provided pre-and post-treatment data. Results: A total of 352 subjects in CI-treatment groups across three clinical trials and 104 subjects in a placebo group provided pre-and post CI-treatment data on the improvements of reading performance in school aged children. The cumulative within-group treatment effect size (0.21(SD 0.03) [95%CI: 0.15, 0.27]) and the cumulative within-group placebo effect size (0.22(SD 0.05) [95%CI: 0.13, 0.32]) for the improvement of reading performance after CI-treatment in school aged children with CI was calculated. Conclusion: CI-treatment has little to no true effect size on reading performance. Though CI-treatments will cause an increase in reading performance, this is likely caused by improvements in attention, motivation, or other psychological factors (placebo effect).