Reviewed by Kelsey Deitz, OD
Pediatrics & Vision Therapy Resident Southern College of Optometry
Convergence insufficiency is an important binocular vision dysfunction. It is characterized by a greater exophoria at near than at distance, a reduced near point of convergence, and a decreased positive fusional vergence at near. It can cause various symptoms when attempting near work including headaches, diplopia, words moving on the page, and asthenopia. Convergence insufficiency is frequently seen in conjunction with children with ADHD, with 19.5% of symptomatic ADHD patients also exhibiting CI. This article details a study that was done to determine if improving symptomatic convergence insufficiency via vision therapy would decrease these patient’s symptom scores for ADHD.
Eighty-one children from eight to thirteen years of age with symptomatic ADHD as determined by the K-ARS survey were pooled together at the start of this study. Sixteen were determined to have CI without any additional accommodative anomalies. The sixteen subjects that exhibited both CI and ADHD were divided into two groups, a control group and a vision therapy (VT) group. All of these subjects were found to be of good health, taking no medications, and free of amblyopia and strabismus. Measurements taken on these subjects included a corrected refractive error, near point of convergence, fusional vergence facility, horizontal Von Grafe phorias at distance and near, and negative and positive fusional vergences. The qualifying criteria included high exophoria at near (at least 6 pd) and higher exophoria at near than at distance (difference of at least 4 pd), as well as inadequate PFV at near, failing Sheard’s criterion, or a base out blur or break ≤ 15 pd. The VT group was given thirty minutes of home and office-based therapy five times a week, and the control group was instructed to go about normal daily activities. After twelve weeks, the K-ARS questionnaire was distributed again.
After the twelve weeks, most of the changes in the CI findings were significantly improved. The near point of convergence significantly neared, although the improvement in fusional vergence facility was not significant. Both the break and recovery of PFV significantly increased after VT, and for NFV the break point alone was found to be significant. Near exophoria was also seen to decrease significantly after VT. In addition to these improvements in CI, the scores found on the K-ARS significantly decreased after the twelve weeks of VT. It is important to note that various symptoms improved on these surveys, not just a single symptom.
This study shows that there is a great overlap between patients with symptomatic ADHD and those with CI. The implication of this study is that those patients with both conditions can effectively decrease their K-ARS scores and become less symptomatic for ADHD by improving vergence movements at near. Because CI is a treatable disorder, the results serve as a good argument to screen symptomatic ADHD children for CI, and recommend VT as appropriate for potential improvement of quality of life for both the patient and family.