Researchers have found that vergence facility and accommodative amplitude drive deficits in developmental eye movement (DEM) test performance post-concussion. Oculomotor assessments such as the DEM and King Devick tests are sideline tools used to screen for concussion and determine return-to-play immediately following injury.

A retrospective, non-randomized, single-center consecutive case series study examined 100 patients over four years. In these adolescents, 52% had their first lifetime concussion and 44% were sports-related. In over 90% of the individuals, the clinical data showed quantifiable accommodation and vergence deficits.

A receded near point of convergence and reduced accommodative amplitudes were the most common vergence and accommodative deficits, respectively. Both of these deficits predicted performance (measured in time) on vertical DEM, while accommodative amplitude predicted performance on horizontal DEM. Analysis revealed vergence facility as the only individual significant predictor for horizontal DEM time, and vergence facility and accommodative amplitude as significant predictors of vertical DEM time.

The study concluded that knowledge of quantifiable accommodative, vergence and visual tracking deficits may guide further study into the underlying pathophysiology of visual deficits post-concussion and may improve management strategies for post-concussion patients.