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Purpose: To describe CONCUSS, a randomized clinical trial (RCT) designed to compare the following: the effectiveness of immediate office-based vergence/accommodative therapy with movement (OBVAM) to delayed OBVAM as treatments for concussion-related convergence insufficiency (CONC-CI) to understand the impact of time (watchful waiting), the effect of OBVAM dosage (12 versus 16 therapy sessions), and to investigate the underlying neuro-mechanisms of OBVAM on CONC-CI participants. Methods: CONCUSS is an RCT indexed on https://clinicaltrials.gov/study/NCT05262361 enrolling 100 participants aged 11–25 years with medically diagnosed concussion, persistent post-concussive symptoms 4–24 weeks post-injury, and symptomatic convergence insufficiency. Participants will receive standard concussion care and will be randomized to either immediate OBVAM or delayed (by six weeks) OBVAM. At the Outcome 1 examination (week 7), clinical assessments of success as determined by changes in the near point of convergence (NPC), positive fusional vergence (PFV), and symptoms will be compared between the two treatment groups. After the Outcome 1 visit, those in the delayed group receive 16 visits of OBVAM, while those in the immediate OBVAM group receive four more therapy visits. Outcome 2 assessment will be used to compare both groups after participants receive 16 sessions of OBVAM. The primary measure is the between-group differences of the composite change in the NPC and PFV at the Outcome 1 visit. Secondary outcome measures include individual clinical measures, objective eye-tracking parameters, and functional brain imaging. Conclusions: Major features of the study design include formal definitions of conditions and outcomes, standardized diagnostic and treatment protocols, a delayed treatment arm, masked outcome examinations, and the incorporation of objective eye movement recording and brain imaging as outcome measures. CONCUSS will establish best practices in the clinical care of CONC-CI. The objective eye movement and brain imaging, correlated with the clinical signs and symptoms, will determine the neuro-mechanisms of OBVAM on CONC-CI. [ABSTRACT FROM AUTHOR]

This study sought to test the hypothesis that significant differences would be observed in clinical measures, symptoms, and objective assessments of vergence eye movements between children with typically developing convergence insufficiency (TYP-CI) and children with persistent post-concussion symptoms with convergence insufficiency (PPCS-CI). Data from age-matched binocularly normal controls (BNC) were used for comparison. Data from three groups of children 11 to 17 years of age are presented: BNC (N = 11), TYP-CI (N = 10), and PPCS-CI (N = 15). Clinical measures of vergence, accommodation, and symptom severity were collected. Symmetrical 4° disparity vergence eye movements were quantified with an eye tracker integrated into a head-mounted display (Oculus DK2). Peak velocity and final response amplitude of convergence and divergence eye movement responses were assessed. The mean near point of convergence (break) was more receded (worse), the amplitude of accommodation more deficient, and convergent and divergent peak velocities slower in the PPCS-CI group compared with the TYP-CI and BNC groups. These results suggest that PPCS-CI may be a different clinical entity than TYP-CI. Hence, more research is warranted to determine whether the therapeutic interventions that are effective for TYP-CI can also be used for PPCS-CI populations. [ABSTRACT FROM AUTHOR]

Purpose: To describe the design and methodology of the Convergence Insufficiency Neuro-mechanism in Adult Population Study (CINAPS), the first randomized clinical trial (RCT) studying young adults with symptomatic convergence insufficiency (CI) using a combination of traditional clinical tests, objective eye movement recordings, and functional brain activities as outcome measures. Methods: In this double-masked RCT, binocularly normal controls (BNC) (N = 50) and CI patients (N = 50) are randomized into office-based vergence/accommodative therapy (OBVAT) or office-based placebo therapy (OBPT). Outcome measures included clinical signs and symptoms, phoria adaptation, forced fixation disparity curves, binocular rivalry, vergence and saccadic objective eye movements, and task-induced functional brain activities. This study is registered on ClinicalTrials.gov NCT03593031. Results: No significant baseline differences are observed between the BNC (p >.4) or CI (p >.3) participants assigned to OBVAT or OBPT for age, near point of convergence (NPC), positive fusional vergence (PFV), phoria at distance and near, amplitude of accommodation, or the Convergence Insufficiency Symptom Survey (CISS). Significant differences are observed between the CI and BNC cohorts at baseline measurements for NPC, PFV, difference in phoria from far to near, amplitude of accommodation, and CISS (p <.001). For the CI patients, 26% had a comorbidity of accommodation insufficiency, and 16% self-reported ADHD. Conclusion: Features of the study design include the following: standardized diagnostic and office-based therapeutic intervention, placebo treatment arm, masked clinical outcome examinations, objective eye movement recordings, functional imaging, phoria adaptation, fixation disparity curves and binocular rivalry measurements. [ABSTRACT FROM AUTHOR]

This study sought to determine whether symmetrical compared to asymmetrical horizontal prisms (base-out or base-in) evoked different rates of phoria adaptation. Sixteen young adults with normal binocular vision participated in a symmetrical phoria adaptation experiment using a 3Δ base-out or 3Δ base-in binocular prism flipper and an asymmetrical phoria adaptation experiment using a 6Δ base-out or 6Δ base-in monocular wedge prism. The experiments were randomized and counterbalanced to reduce the influence of the prism stimulation order. Asymmetrical base-out prism adaptation was significantly faster than symmetrical prism adaptation for subjects with normal binocular vision. Asymmetrical phoria adaptation with base-in prism was not significantly different from symmetrical phoria adaptation implying that there are directional asymmetries (convergent versus divergent eye movements) in the slow fusional component of vergence. Data suggest that a potential interaction between the version system and the slow fusional vergence system may exist. Results have clinical relevance because patients with convergence or divergence insufficiency/excess may potentially show more pronounced differences between symmetrical and asymmetrical phoria adaptation compared to binocularly normal controls. These differences might also be relevant to clinical measurements such as vergence fusional range, which can be measured symmetrically (with Risley prisms in a phoroptor) or asymmetrically (with prism bar). [ABSTRACT FROM AUTHOR]