PURPOSE: To prospectively evaluate the effectiveness of home-based computer vergence therapy for treatment of binocular vision disorders in adults, ages 18-85, at least 3 months post brain injury.
METHODS: Eligibility criteria included presence of binocular or accommodative dysfunction characterized by receded near point of convergence (NPC) (greater than or equal to 6 cm break), insufficient positive fusional vergence (PFV) at near (failing Sheard’s criterion or less than 15Δ blur or break), insufficient negative fusional vergence (NFV) at near (less than 12Δ blur or break), reduced vergence facility with 12ΔBO/3ΔBI at near (less than 15 cpm), and/or below minimum expected amplitude of accommodation for age. All subjects were prescribed 12 weeks of home-based computer vergence therapy. Phoria (cover test), NFV at near, PFV at near, NPC, vergence facility, accommodative amplitude and facility (nonpresbyopes only), 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. Percent successful also was determined.
RESULTS: Of the 19 subjects enrolled (mean age 45.4 ± 12.9 years), 15 suffered external mechanical trauma to the head, 3 suffered cerebrovascular accident, and 1 suffered from organic brain syndrome. Six subjects were lost to follow-up. The binocular profile of the cohort at baseline was orthophoria (SD=1.08) at distance, 7.11Δ (SD=5.19) exophoria at near, NPC break = 17.07 cm (SD=10.56), NPC recovery = 21.48 cm (SD=11.66), near NFV = 12.33Δ (SD=4.37), near PFV = 8.80Δ (SD=5.69), vergence facility = 4.06 cpm (SD=4.41), and CISS = 31.12 (SD=12.93). ANOVA showed statistically significant improvement for NPC break (p=0.002) and recovery (p less than .001), PFV blur (p less than .0001), break (p less than .0001), and recovery (p less than .0001), NFV blur (p=0.047), break (p=0.008), and recovery (p=0.017), vergence facility (p less than .0001), and CISS (p less than .0001). The percentage of patients who were classified as “successful” or “improved” was 69% for NPC (less than 6 cm or a decrease of greater than 4 cm), 77% for PFV (greater than 15Δ and passing Sheard’s criterion or an increase of greater than or equal to 10Δ), 77% for NFV (greater than or equal to 12Δ or an increase of greater than or equal to 6Δ), 69% for PFV and NFV, 92% for vergence facility (15 cpm or an increase of 3 cpm), and 62% for CISS (less than 21 or a decrease of greater than or equal to 10 points).
CONCLUSIONS: The majority of the 68% of subjects who completed the study experienced meaningful improvements in signs and symptoms.