Convergence insufficiency prevalence in attention deficit and hyperactivity disorder children depends on the diagnosis criteria.

Purpose: Attention deficit and hyperactivity disorder (ADHD) is a neurodevelopmental condition commonly seen in children and adolescents, characterised by an increase in distractibility or inattention. Several studies have noted a higher rate of visual problems in this group, especially convergence insufficiency (CI), but when using different diagnostic criteria. The aim of this study was to evaluate visual function in ADHD children and non-ADHD controls to compare the different signs for diagnosis of CI.

Method: In this prospective case-control study, a group of children aged 7-17 years, diagnosed with ADHD before the start of pharmacological treatment and matched for age and gender with non-ADHD controls were examined. Visual acuity (VA), objective and subjective refraction, accommodative amplitude and facility, heterophoria, positive and negative fusional vergences (PFV and NFV) and stereopsis were assessed.

Results: Sixty participants (30 ADHD and 30 non-ADHD controls) were evaluated. There was no significant difference between the two groups for VA, refraction and accommodative abilities. There were significant differences in PFV and NFV: PFV break/recovery values for the ADHD and control groups were 18.9/16.2∆ and 26.9/22.1∆, respectively. Respective values for NFV were 15.7/13∆ and 19.3/15.9∆. Using the three signs of receded near point of convergence (NPC), decreased PFV and exophoria 4∆ greater at near than distance, the prevalence of CI was equivalent for the ADHD and controls (p = 0.34) If only two signs were considered for the CI diagnosis, (i.e., receded NPC and decreased PFV), then prevalence was significantly greater for the ADHD group (p < 0.01).

Conclusions: These results show a higher prevalence of binocular vision problems in the ADHD group. This suggests a relationship between vergence problems and ADHD, but the direction of this link remains unclear. Further studies with specific samples may be needed to understand fully the association between binocular vision disorders and ADHD.