Significance: These data confirm the effectiveness of office-based vergence/accommodative therapy for improving convergence in children with symptomatic convergence insufficiency. They also highlight the importance of using a primary outcome measure that is as objective as possible rather than relying solely on self-reported symptoms for studies of binocular vision in children.
Purpose: The purpose of this study was to report changes in clinical signs and symptoms of convergence insufficiency (secondary outcome measures) from a multicenter clinical trial (Convergence Insufficiency Treatment Trial-Attention & Reading Trial [CITT-ART]) evaluating the effectiveness of vergence/accommodative therapy for improving reading and attention in children with symptomatic convergence insufficiency.
Methods: Three hundred eleven children aged 9 to 14 years with symptomatic convergence insufficiency were randomly assigned to 16 weeks of office-based vergence/accommodative therapy or to placebo therapy. Improvements in (1) near point of convergence (NPC), (2) positive fusional vergence (PFV), and (3) self-reported symptoms (Convergence Insufficiency Symptom Survey [CISS] score) were compared after 16 weeks of treatment.
Results: Mean NPC improved 10.4 cm in the vergence/accommodative and 6.2 cm in the placebo therapy group (mean difference of -4.2 cm [95% confidence interval {CI}, -5.2 to -3.2 cm; P < .001]); mean PFV increased 23.2 and 8.8Δ in the vergence/accommodative and placebo therapy groups, respectively (mean difference of 14.4Δ [95% CI, 12.1 to 16.8Δ; P < .001]). The mean CISS score improved 11.8 and 10.4 points in the vergence/accommodative and placebo therapy groups, respectively (mean difference of 1.5 points [95% CI, -3.8 to +0.8 points; P = .21]).
Conclusions: Our results demonstrate that office-based vergence/accommodative therapy is effective for improving the NPC and PFV in children with symptomatic convergence insufficiency. However, given that both treatment groups had a similar reduction in self-reported symptoms, it may not be prudent to use the CISS alone as a measure of successful treatment.
Trial registration: ClinicalTrials.gov NCT00338611.