Objective: To determine the test-retest correlation of an objective eye-tracking device among uninjured youth athletes.
Design: Repeated-measures study.
Setting: Sports-medicine clinic.
Participants: Healthy youth athletes (mean age = 14.6 ± 2.2 years; 39% women) completed a brief, automated, and objective eye-tracking assessment.
Independent variables: Participants completed the eye-tracking assessment at 2 different testing sessions.
Main outcome measures: During the assessment, participants watched a 220-second video clip while it moved around a computer monitor in a clockwise direction as an eye tracker recorded eye movements. We obtained 13 eye movement outcome variables and assessed correlations between the assessments made at the 2 time points using Spearman's Rho (rs).
Results: Thirty-one participants completed the eye-tracking evaluation at 2 time points [median = 7 (interquartile range = 6-9) days between tests]. No significant differences in outcomes were found between the 2 testing times. Several eye movement variables demonstrated moderate to moderately high test-retest reliability. Combined eye conjugacy metric (BOX score, rs = 0.529, P = 0.008), the variance of the ratio for both eye movements in the horizontal (rs = 0.497, P = 0.013) and vertical (rs = 0.446; P = 0.029) movement planes along the top/bottom of the computer screen, and the variance of the left and right eye movement along the bottom segment of the computer screen (rs = 0.565; P = 0.004) each demonstrated moderate between-test correlations.
Conclusions: Automated and quantitative eye movement and conjugacy metrics provide relatively stable measurements among a group of healthy youth athletes. Thus, their inclusion as a visual tracking metric may be complementary to other visual examination techniques when monitoring concussion recovery across time.