Near Point of Convergence Deficits and Treatment Following Concussion: A Systematic Review

Abstract

Context: Convergence dysfunction following concussion is common. Near point of convergence (NPC) is a quick and easy assessment that may detect oculomotor dysfunction such as convergence insufficiency (CI), but NPC measurements are rarely reported. Convergence dysfunction is treatable in otherwise healthy patients; the effectiveness of oculomotor therapy following concussion is unclear. Objectives: The purpose of this article was to systematically review the literature and answer the following clinical questions: (1) Is performance on NPC negatively affected in patients diagnosed with a concussion compared with pre-injury levels or healthy controls? (2) In patients diagnosed with concussion, what is the effect of oculomotor/vision therapy on NPC break measurements? Evidence Acquisition: The search was conducted in CINAHL, SPORTDiscus, MEDLINE, and PubMed using terms related to concussion, mild traumatic brain injury, convergence, vision, and rehabilitation. Literature considered for review included original research publications that collected measures of NPC break in concussion patients, with a pretest–posttest comparison or comparison with a healthy control group. A literature review was completed; 242 relevant articles were reviewed, with 18 articles meeting criteria for inclusion in the review. Evidence Synthesis: Articles were categorized according to the clinical question they addressed. The patient or participant sample (number, sex, age, and health status), study design, instrumentation, or intervention used, and main results were extracted from each article. Conclusions: The authors' main findings suggest that there is a moderate level of evidence that patients have impaired NPC up to several months postconcussion, and a low level of evidence that impairments can be successfully treated with oculomotor therapy. These findings should be cautiously evaluated; the studies are limited by weak/moderate quality, small sample sizes, varied methodology, and nonrandomized treatment groups. Future research should explore factors affecting convergence postconcussion and include randomized, controlled studies to determine if performing vision therapy improves visual measures and promotes recovery.