Background:Vision encompasses a large component of the brain's pathways, yet is not represented in current sideline testing.Objectives:We performed a meta-analysis of published data for a vision-based test of rapid number naming (King-Devick [K-D] test).Studies & methods:Pooled and meta-analysis of 15 studies estimated preseason baseline K-D scores and sensitivity/specificity for identifying concussed versus nonconcussed control athletes.Result:Baseline K-D (n = 1419) showed a weighted estimate of 43.8 s (95% CI: 40.2, 47.5; I2 = 0.0%; p=0.85 – indicating very little heterogeneity). Sensitivity was 86% (96/112 concussed athletes had K-D worsening; 95% CI: 78%, 92%); specificity was 90% (181/202 controls had no worsening; 95% CI: 85%, 93%).Conclusion:Rapid number naming adds to sideline assessment and contributes a critical dimension of vision to sports-related concussion testing.

The data show worsening of K-D test scores following concussion further supporting utility of the K-D test as an objective, reliable and effective sideline visual screening tool to help identify athletes with concussion.

This study showed that retinal axonal and neuronal loss is present among collision sport athletes, with most notable differences seen in boxers. These findings are accompanied by reductions in visual function and QOL, similar to patterns observed in multiple sclerosis, Alzheimer and Parkinson diseases. Vision-based changes associated with head trauma exposure that have the potential to be detected in vivo represent a unique opportunity for further study to determine if these changes in collision sport athletes are predictive of future neurodegeneration.