AUTHOR=Jorge Jorge , Teixeira José , Pinhão Tiago , Delgado Frederico , Salem Alshaarawi , Martino Francesco , Plainis Sotiris 

TITLE=Self-reported visual symptoms and high visual demand activities in professional football players: a cross-sectional survey

JOURNAL=Frontiers in Sports and Active Living

VOLUME=Volume 5 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2023.1256847

DOI=10.3389/fspor.2023.1256847

ISSN=2624-9367

ABSTRACT=Background: Vision is crucial for football players, impacting decision-making and athletic performance. Despite its global popularity, football lacks comprehensive evaluations of the impact of digital device use on ocular symptoms during high-demand activities.
Purpose: To know the time spent by football players in high visual demands activities, the symptoms associated binocular vision disfunctions and their relationship with sports performance.
Methods: A cross-sectional observational study was conducted in 2020 using an online survey, targeting football players from Portugal, England, Spain, and Saudi Arabia. The survey, distributed over five weeks, aimed to collect data from approximately 5,000 football players. Information on player profiles, competitive levels, vision habits, and symptoms related to binocular vision dysfunctions was collected. The Convergence Insufficiency Symptom Survey (CISS) employed a 5-point Likert scale to indicate the average frequency of each symptom. Due to non-normality, non-parametric tests were used (p < 0.05). Specifically, Man-Whitney U, Kruskal-Wallis, Chi-square, and Spearman's rank correlation tests were used as appropriate.
Results: Analyzing male professional football players (mean age: 27.4 ± 5.0 years, 95% CI, 26.7-28.1), the study found 38.1% as national team call-ups and 6.9% with over 50 games played. Self-rated last season's performance had a mean score of 6.5 ± 2.1 (95%CI, 6.2-6.8 )(on a scale of 1 to 10). Smartphone use exceeded 1 hour daily for all players, with 36.0% surpassing 4 hours. Visual symptoms, notably associated with smartphone use (35.5%), were observed. Regarding the CISS score, the mean was 7.1 ± 7.7 (IC95%: 6.6 to 8.8). A weak negative correlation (rho = -0.215, p = 0.003) emerged between CISS scores and self-perceived sports performance. Football players using prescription lenses had significantly higher CISS scores (11.9 ± 10.4, 95%CI, 12.3-7.7) compared to non-users (6.2 ± 6.8, 95%CI, 7.8-5.7) (p<0.001).
Conclusion: This study reveals that professional football players engage in high visual demand tasks, notably on smartphones. One-third link smartphone use to ocular symptoms. Convergence Insufficiency Symptoms Survey indicates 6.3% exhibit binocular vision dysfunction symptoms. Those with fewer ocular symptoms perceive better sports performance than counterparts.