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.

Oculomotor Deficits and Symptom Severity Are Associated With Poorer Dynamic Mobility in Chronic Mild Traumatic Brain Injury

“…Oculomotor abnormalities such as poorer depth perception, poorer baseline visual acuity, longer near point convergence distance were moderately correlated with poorer functional mobility. Visual deficits have been studied extensively after traumatic brain injury (45,(60)(61)(62)(63)(64)(65)(66), and in combination with vestibular dysfunction have been shown to affect balance (21). Kleffelgaard et al examined 65 individuals (mean age 39.2 ± 12.9 years) who were 3 months post-injury and reported that 78% had poorer high-level balance while 77% had lower scores on high level mobility tasks compared to normative values.…”

A Framework to Advance Biomarker Development in the Diagnosis, Outcome Prediction, and Treatment of Traumatic Brain Injury

“…Several oculomotor measures have been investigated for use as potential biomarkers of altered brain function after TBI, including metrics of fixation, smooth pursuit, saccades, 100 and convergence. 101 One study demonstrated that oculomotor assessment may be an indicator of decreased integrity of frontal white matter tracts and of altered attention and working memory functioning. 102 Moreover, researchers have developed mobile eye-tracking devices, which could benefit future clinical research by capturing eye movements remotely.…”

Implementation of Kiosk-Type System Based on Gaze Tracking for Objective Visual Function Examination

“…The closest point at which both eyes can converge inward at the same time is called the near-point-of-convergence (npc) [12,13]. When the npc moves away from the eye, objects appear blurry when performing near work, such as convergence and accommodation insufficiency, and subjective symptoms, such as ophthalmocopia occur.…”