The systems that control eye movement and balance run through some of the brain regions most vulnerable to concussion. That is why visual and vestibular symptoms, blurred focus, dizziness, motion sensitivity, trouble reading, are among the most common complaints after head injury, and why examining those systems is part of a thorough evaluation.
The evidence base is peer reviewed. The Vestibular/Ocular Motor Screening assessment, developed at the University of Pittsburgh Medical Center, provokes and scores symptoms across smooth pursuits, saccades, convergence, vestibulo-ocular reflex, and visual motion sensitivity. In its validation study, 61 percent of concussed patients showed symptom provocation on at least one component, and the combined model identified concussed patients with an area under the curve of 0.89 [].
In children and adolescents the numbers are striking. In a study of adolescents aged 11 to 17 evaluated at a specialty concussion clinic, 69 percent had one or more vision diagnoses after concussion, including accommodative disorders in 51 percent, convergence insufficiency in 49 percent, and saccadic dysfunction in 29 percent [].
Technology now allows parts of this examination to be measured rather than estimated. FDA-cleared eye-tracking systems record and analyze eye movements to support the identification of visual tracking impairment []. Objective measurement matters for the same reason it matters in blood testing: it produces findings that do not depend on subjective report alone.
As with every tool described in this section, these are components of a clinical evaluation. Vestibular and oculomotor findings contribute to a physician's diagnosis. No screening score or eye-tracking result diagnoses a concussion by itself [].