The effects of simulated monocular and binocular vision impairment on football penalty kick performance.

Sports performance is relatively robust under high levels of binocular blur. However, the limited research studies investigating monocular impairments has shown it has a larger impact on sport performance. This research study is relevant for classification in sports for athletes with vision impairment (VI), where visual acuity (VA) from the better eye is used during classification. Across two experiments, we aimed to establish the point at which binocular and monocular impairments affected performance in a football penalty kick (PK) through simulating varying severities of degraded VA and contrast sensitivity (CS) in active football players. In experiment one, 25 footballers performed PKs as VA and CS were systematically decreased in both eyes, and in one condition, visual field (VF) was reduced. The most severe VA/CS condition and reduced VF significantly impacted outcome, ball velocity and placement (ball kicked closer to the centre of the goal) (p < 0.05). In experiment two, 29 different footballers performed PKs as VA and CS of only the dominant eye were systematically decreased and in one condition the dominant eye was occluded, and participants viewed their environment through the non‐dominant eye (monocular viewing). No differences were observed when assessing monocular impairments influence on outcome, velocity and ball placement. PKs have a high resilience to VI, but binocular impairment has a more immediate effect, suggesting binocular measures should be used in classification processes in football. Highlights: Penalty kick (PK) performance was relatively robust to severe artificial binocular visual impairment. Performance reduced at 1.96 logMAR, causing the ball to be kicked slower (lower velocity) and closer to the centre of the goal.Monocular viewing or impairment did not influence the velocity at which the ball was kicked or where the ball was placed. Therefore, PK performance was maintained at the habitual level.The evidence suggests that PK performance is more sensitive to binocular impairments than monocular impairments. Therefore, it may be beneficial for footballers with vision impairment to be classified using binocular assessments. [ABSTRACT FROM AUTHOR]