Professional baseball players demonstrate superior dynamic visual acuity and differences in vestibulo-ocular reflex performance, compared to similarly aged healthy controls

BACKGROUND: Baseball-specific movement paradigms require heightened ocular performance driven by the vestibular system. Normative data of vestibulo-ocular measures for high-level athlete populations is limited in the current literature, particularly under game-like conditions. This comparative cross-sectional study explores the vestibulo-ocular performance of professional baseball players, relative to healthy controls. METHODS: The computerized dynamic visual acuity (cDVA) test compared visual acuity during active head impulses in both horizontal and vertical planes relative to a static visual acuity measure. The video head impulse test (vHIT) measured the vestibulo-ocular reflex (VOR) gain (i.e., ratio of eye velocity to head velocity) of passive horizontal head impulses under typical and high velocity conditions. An analysis of covariance (ANCOVA) approach was then used to determine the differences between a group of professional baseball players and a similarly aged control group. RESULTS: The baseball players had significantly better acuity for each condition: static (p value = 0.005), horizontal (p value < .001), and vertical (p value = 0.021) of the cDVA test relative to the healthy controls. Additionally, mean difference in VOR gain between the high velocity and typical velocity head rotations during vHIT testing was significantly greater in the baseball players relative to the healthy controls (p value = 0.036). CONCLUSION: Through years of sport-specific training, professional baseball players are hypothesized to develop improved dynamic visual acuity as characterized by excellent performance in the cDVA test and disconjugate VOR gains across high velocity vHIT and typical velocity vHIT potentially due to greater eye acceleration during the initial milliseconds of a head impulse.