Dynamic Visual Acuity Test To Denote Visuomotor Changes In Adolescents Participating In High Impact Sports

Abstract

Repetitive head impacts (RHI), independent of concussion, can have a negative influence on the visual system but data are sparse in adolescent contact athletes. PURPOSE: Evaluate the effect of repetitive head impacts influence on adolescent football players oculomotor and vision throughout the mid-point of a single contact season using a dynamic visual acuity (DVA) task. METHODS:4 NIAA Varsity and JV football high school players (all males) with ≤20/20 static visual acuity with or without corrective lenses participated in this study. Student-athletes were evaluated prior (PRE) to the start of the season and in the middle (MID) of the season. The football players all wore instrumented mouthguards to track head impacts during each practice and game. Every participant completed 120 randomized trials of smooth pursuit (SPEM) (30°/s) and saccadic (90°/s) eye movements at (PRE) and (MID) of the season. All participants eye movements were tracked by (500 Hz; Eyelink SR research, Ottawa, CN) while their heads were stable in a chin rest 150 cm away from a 26° monitor. Participants were tasked to determine the orientation of Landolt-C’s openings (left, right, up, down) that moved across the monitor (horizontally left to fight) using a keypad. Depending on the correct/incorrect responses during the smooth pursuit and saccadic trials, the size of the C’s would either increase or decrease in size (2-up, 1-down staircase). Between each trial, a retinal flush image was presented for 2 ms before the appearance of a fixation cross. Smoot pursuit eye movement (SPEM) gain, and vision alongside saccadic peak velocity were evaluated at each time point. RESULTS: No significant difference was noted at PRE (1.09 ± 0.04) to MID (1.07 ± 0.08; p = 0.33, Cohen’s d = 0.32) for SPEM gain and for saccadic peak velocity (PRE = 386.70 ± 36.94 m/s, MID = 397.20 ± 2.12 m/s; p = 0.935, Cohen’s d = 0.33). Similarly, no difference was noted for SPEM Vision at PRE (20/32) and MID (20/32; p = 0.71) and for saccades (PRE = 20/40, MID = 20/40; p = 0.935). Participants had ≤20/20 static visual acuity at both time points. CONCLUSIONS: Oculomotor control and vision do not decline in the presence of RHI from the beginning to the middle of a contact football season in adolescents. Additional data are needed given the strength of the effect size.