The results of this study suggest that clinicians providing vergence/accommodative therapy for convergence insufficiency in children should not suggest that such treatment will lead to improvements in attention when compared with placebo treatment.
This study aimed to compare the effects of 16 weeks of vergence/accommodative therapy and placebo therapy on changes in attention for children in the Convergence Insufficiency Treatment Trial–Attention and Reading Trial.
Three hundred ten children 9 to 14 years old with convergence insufficiency were assigned to receive treatment with office-based vergence/accommodative therapy or placebo therapy. Attention tests were administered at baseline and after 16 weeks of treatment. The primary measure of attention was the Strengths and Weaknesses of Attention-Deficit/Hyperactivity Disorder Symptoms and Normal Behavior (SWAN) scale. Other measures included the Swanson, Nolan, and Pelham checklist; the Homework Problems Checklist; and the d2 Test of Attention. Within and between-group differences are reported using Cohen d effect sizes.
For the SWAN, there was no significant difference between the groups for the inattention scale parental report (d = 0.036; 95% confidence interval, −0.21 to 0.28) or for the hyperactivity impulsivity scale parental report (d = −0.003; 95% confidence interval, −0.24 to 0.24). Similar results were found for teacher reports and the secondary measures (d estimates from −0.97 to +0.10). There were, however, large within-group changes with d ≥ 1 in both treatment groups for the SWAN, the Homework Problems Checklist, and the d2 Test of Attention.
These results suggest that vergence/accommodative therapy is no better than placebo therapy in improving attention. Large improvements in inattention, completing homework, and selective and sustained attention were found in each group. However, these improvements cannot be attributed to improvements in vergence and accommodation and are likely due to nonspecific effects of an intensive therapy regimen.