Effectiveness of office-based vergence/accommodative therapy with movement for accommodative dysfunction in concussion-related convergence insufficiency: a secondary analysis of the CONCUSS randomised clinical trial

OBJECTIVES: To determine the effectiveness of office-based vergence/accommodative therapy with movement and home reinforcementt (OBVAM) for improving visual accommodative amplitude and facility in concussion-related convergence insufficiency with coexisting accommodative disorders. METHODS: In this secondary analysis of the CONvergence Insufficiency in Persistent Post-CUSsion Symptoms (CONCUSS) randomised clinical trial, 79% (84/106) of participants with persisting symptoms 4-24 weeks after their last concussion, aged 11-25 years, had visual accommodative disorders. Participants were randomised to immediate OBVAM (12 sessions, two times per week) or delayed OBVAM for 6 weeks of watchful waiting. Then the outcome time 1 assessment compared accommodative amplitude (the maximum accommodative demand measured in dioptres (D) that a person can perceive clearly) for each eye monocularly and accommodative facility (a measure of how many times a participant could see an image clearly through a +2 D and -2 D lens within 1 min) between groups. Following outcome time 1 assessment, the immediate group completed four additional OBVAM sessions and the delayed group completed 16 OBVAM sessions two times per week. Outcome time 2 assessment occurred with both groups completing 16 OBVAM sessions. Analyses compared within and between group changes to assess the impact of therapy timing and additional sessions. RESULTS: For outcome time 1 assessment, the immediate group (after 12 OBVAM sessions) showed significantly greater improvements (p<0.001) in accommodative amplitude, right eye: 4.7 D (95% CI 3.7 to 5.7) (6.3 cm); left eye: 5.1 D (95% CI 4.0 to 7.1) (6.8 cm), compared with the delayed group (watchful waiting), right eye: 1.0 D (95% CI 0.2 to 1.8) (1.3 cm); left eye: 1.0 D (95% CI 0.1 to 1.9) (1.3 cm). Accommodative facility at outcome time 1 assessment also improved more in the immediate group (5.1 cycles per minute (cpm) (95% CI 2.7 to 7.5)) than in the delayed group (2.4 cpm (95% CI 0.3 to 4.5)). For outcome time 1 assessment, participants with accommodative insufficiency, 86% in the immediate group, achieved resolution compared with 28% in the delayed group. No significant difference was observed between outcome time 1 and 2 assessments for the immediate group, comparing the 12-16 OBVAM sessions for accommodative function. When comparing the immediate and delayed groups at the outcome time 2 assessment (both groups received all 16 OBVAM sessions), no significant differences were observed between groups in accommodative function. CONCLUSION: OBVAM improves accommodative amplitude and facility following concussion. While delayed treatment did not impact the improvement of accommodative function, immediate therapy accelerates recovery and fosters a faster return to activities compared with delayed treatment. The CONCUSS study has previously reported an improvement in oculomotor convergence function, with a reduction in visual symptoms post-OBVAM compared with baseline measurements. If accommodative or convergence dysfunctions are identified in those with persisting symptoms after concussion, then intervention is recommended to expedite return to learn, sports and work.