Vision Therapy for Binocular Dysfunction Post Brain Injury.

Abstract

To prospectively evaluate the effectiveness of home-based computer vergence therapy for the treatment of binocular vision disorders in adults at least 3 months after an acquired brain injury. Eligibility criteria included presence of binocular dysfunction characterized by receded near point of convergence (≥6 cm break), insufficient positive fusional vergence at near (failing Sheard's criterion or <15△ blur or break), insufficient negative fusional vergence at near (<12△ blur or break), and/or reduced vergence facility at near (<15 cycles per minute with 12△BO/3△BI). Participants were prescribed 12 weeks of home-based computer vergence therapy. Phoria (cover test), negative fusional vergence, positive fusional vergence, near point of convergence, vergence facility, and symptoms (convergence insufficiency symptom survey [CISS]) were assessed at baseline and after 4, 8, and 12 weeks of prescribed therapy. ANOVA was used to evaluate change in each measure. Percentage successful was also determined. Nineteen participants were enrolled (mean age 45.4 ± 12.9 years); six participants were lost to follow-up. Baseline findings were orthophoria at distance, 7.2△ exophoria at near, near point of convergence break = 17.5 cm, near point of convergence recovery = 21.8 cm, negative fusional vergence = 12.3△, positive fusional vergence blur = 8.4△, vergence facility = 3.9 cycles per minute, and CISS = 32.1. ANOVA showed a statistically significant improvement for near point of convergence break (p = 0.002) and recovery (p < 0.001), positive fusional vergence blur (p < 0.0001), break (p < 0.0001), and recovery (p < 0.0001), negative fusional vergence blur (p = 0.037), break (p = 0.003), and recovery (p = 0.006), vergence facility (p < 0.0001), and CISS (p = 0.0001). The percentage of patients who were classified as "successful" or "improved" was 69% for near point of convergence (<6 cm or decrease of ≥4 cm), 77% for positive fusional vergence (>15△ and passing Sheard's criterion or increase of ≥10△), 77% for negative fusional vergence (≥12△ or increase of ≥6△), 62% for positive fusional vergence and near point of convergence composite, and 92% for vergence facility (15 cycles per minute or increase of 3 cycles per minute). The majority of participants who completed the study experienced meaningful improvements in signs and symptoms.