Review: Vision and On-field Performance: A Critical Review of Visual Assessment and Training Studies with Athletes.

Sports vision is an emerging field that seeks to establish the relationships between visual function and sports performance. Here we provide the first critical review of empirical studies that attempt to link visual assessments and vision training to competitive game performance.Vision is essential to producing controlled movement, and therefore, it is intuitive that better visual abilities should relate to better sporting performance. This notion has been central to the field of sports vision, an area of study that seeks to determine the visual skills that underlie optimal sports performance and investigate approaches to train these abilities to improve sports performance. Although this field now contains hundreds of published articles addressing visual assessment and training in athletes, relatively few have attempted to directly link these capabilities to on-field production statistics from competitive matches. The objectives of this article are both to describe the theoretical and experimental framework necessary for such research and to critically review the empirical literature that has attempted to directly link visual assessments and/or training to athletic performance. We begin by describing why such associations are important and then provide an evidence-based framework for evaluating the quality of research in this domain. This is followed by a summary and review of the qualified literature that has addressed either relationships between baseline assessments and game performance or the effects of visual training interventions on game performance. Based on this review, it is concluded that, despite promising evidence supporting the role of vision in sports performance and improvements due to training, the specialty is still in need of methodological improvements. It is recommended that studies aim for larger better-powered studies, consistent and precise outcome measures, and greater scientific rigor such as obtained through randomized placebo-controlled designs with pre-registration of hypotheses.