A Sports Vision Assessment will provide an in-depth analysis of an athlete’s visual system, and this information can be used to predict potential deficits in visual performance, particularly under conditions of physical and mental fatigue, or specific areas of space.
A Sports Vision Assessment has two purposes:
- To identify any areas of weakness in visual skills that may potentially hamper performance as an athlete fatigues due to physically and emotional stresses during play.
- To provide a baseline of current visual skills from which to develop a visual skill enhancement program.
Vision coaching or training may then be employed to reinforce visual skills generally, focusing initially upon individual areas of visual need and sport specific visual skill requirements. The ultimate goal is to enhance existing visual skills in order to assist an athlete in achieving their full sporting potential and increase competitive advantage
The areas of visual skill analysed during an assessment may vary with sport and position, but some of the more typical skills are explained below.
Visual skills areas
Three types of sight or acuity may be assessed: static, dynamic, and contrast sensitivity. The extent to which each is important may depend upon the particular sport and conditions of play.
- Static Acuity
Static acuity is the ability to clearly see a stationary target at 100% contrast (black on white). Obviously these viewing conditions are not typical in dynamic sports and measures such as dynamic visual acuity and contrast sensitivity may have more relevance.
- Dynamic Visual Acuity
Dynamic visual acuity measures the ability to see clearly when there is relative movement between the player and the object viewed, such as when either or both are in motion. Good dynamic visual acuity is dependent partly upon good static acuity and partly upon the ability to efficiently and effortlessly synchronise the eye and head movement necessary to keep the image of a moving target stable on the macula area of the retina during body movement.
- Contrast Sensitivity
Contrast sensitivity is the ability to perceive shading differences between two objects, often necessary in order to differentiate an object from its surrounding background. Contrast sensitivity influences the ability to discriminate detail (despite good static acuity) under varying light conditions, such as overcast weather, and against varying background colours, such as when the ball passes in front of the stadium crowd or stadium lights.
Refraction is the determination of long or short sightedness or astigmatism, which may impact upon all three measures of sight above and, hence, interfere with best performance in sport. Refraction gives an indication of where in space the eyes are habitually focusing/posturing relative to where a distant target actually is, and generally equates with an individual’s prescription for glasses. If it is necessary to compensate for any refraction contact lenses will generally allow better awareness of peripheral space.
Hand and Eye Dominance
Generally the dominant eye is the eye that will primarily be ‘signalling’ the brain with the information needed to judge direction, distance and speed of an object as it comes towards a player.
Colour vision tests assess the ability to discriminate between different colours. Deficits in colour vision can make it difficult to identify team players where the opponents’ kit involves confused colours and may make it difficult to see a ball against a similarly ‘confusing’ background, despite adequate static and dynamic acuity and good contrast sensitivity. It is not possible to treat colour vision anomalies but specially tinted contact lenses are reported to help with color discrimination and could be used if necessary. Alternatively awareness can allow for advice on possible compensations.
Focusing and Vergence
Focusing can be thought of as “homing in” on a target in space, and accurate focusing is all about WHERE a person perceives an object to be relative to himself, and how quickly and consistently he can determine this. Speed, flexibility and resilience in focusing are required in order to rapidly re-evaluate spatial judgements in a fast moving dynamic environment, while both ball and players are in constant motion.
Vergence is the simultaneous movement of both eyes in opposite directions (may be asymmetric) to keep both aligning on the target as it moves closer or further away. Under normal conditions, changing the focus of the eyes to look at an object at a different distance will automatically cause a vergence change and, consequently, a good equilibrium between focusing and vergence is a major component of accurate purposeful tracking, as in “keeping your eyes on the ball”.
Binocular stability is particularly dependent upon a good equilibrium between focusing and vergence under conditions of increasing stress and fatigue, both of which may impact adversely upon the focusing-vergence relationship. Various tests are used to evaluate the stability and consistency of eye alignment and eye teaming for targets in different directions of gaze. This is an important factor in accurate spatial, for consistent catching, kicking and passing, over time and with increasing physical and mental fatigue.
A saccade or jump movement is used to move quickly from one object to another and a pursuit or following movement is used to track a moving object. Both types of eye movement are evaluated, in terms of accuracy, consistency, speed and resilience, under various conditions.
Perception of depth is essentially about the three dimensional nature of space and solid objects. Every solid object occupies a volume of space and is surrounded by a volume of space, separating it from the next object. Efficient depth perception allows us to be more aware of the space between objects so that we can more accurately and consistently judge the distance of an object, the relative distances of several objects, and the change in distance over time, or speed. This is important if one player is to accurately intercept another moving at speed, jump to catch a high ball or time a pass to reach a player as he moves into open space. Enhanced depth perception will allow a player to be more aware of space around himself and other players, allowing better anticipation of opening spaces, and gaps breaking in defences. Speed, quality and resilience of stereo acuity are usually measured in a Sports Vision Assessment. Stereo acuity is not exactly the same as depth perception but is a significant contributory factor in effective three dimensional vision.
Balance and Vision
The ability to efficiently combine visual function with motor feedback (visual motor integration) in the planning and execution of purposeful body interaction with fast moving targets during play is particularly important if an athlete is to achieve their full sporting potential. Inadequate visual motor integration could result in vision and eye movements disrupting balance control and, conversely, poor postural stability may hamper efficient pursuit eye movements, reducing dynamic acuity, and the accuracy of spatial perceptions.
Visual-Motor Performance Tests
Hand/foot to eye co-ordination
A Sports vision assessment will often involve some composite performance tests reliant upon efficient integration of visual input and motor action, such as pro-action and reaction tasks in response to rapidly changing visual stimuli. Tests of this nature may be used to evaluate hand to eye or foot to eye co-ordination.
Visual Anticipation could be described as the ability to “see” what might happen next, based upon visualized projections of speed and direction of moving objects, for example, where a ball will be by the time an approaching player reaches it, or where space will open up in front of a player given the speed and direction of surrounding players. Good visual anticipations skills can compensate, to some extent, for the physical limitations of reaction time, thus improving overall response times. Essentially this is a skill that is dependent upon multiple other factors that come together and operate in unison, as required. Examples are static and dynamic (also dependent upon good eye movements) acuity, contrast sensitivity, eye movements (dependent upon good vergence and accommodative facility), stereo acuity, glare recovery, visualisation and visual manipulation skills. Improvement in visual anticipation skills will be a natural result of building the contributory visual skills.
A Sports Vision Assessment may include a selection of tasks dependent upon the ability to retain and manipulate visual input, particularly important to visual anticipation, visual prediction and planning game strategy. Automaticity and speed of visualisation and visual manipulation skills relies upon efficient functional control over the visual system so that maximum energy is available for information absorption and retention.
Peripheral Awareness Assessment
Many sports require highly developed peripheral awareness skills and tests may evaluate the speed and accuracy of processing information in peripheral visual space, using tasks that require an action of some sort, such as hitting a button or moving a joystick, in response to peripheral recognition of a visual target in a variety of different visual field locations.
Following sports vision assessment
Following assessment, the results and recommendations will be made in the form of a detailed written report with recommendation for any refractive correction in the most appropriate from, such as contact lenses or sports specific eyewear. Reports will include in-depth analysis of sports related visual skills, highlighting areas of strength and identifying any current, or potential, areas of weakness or risk. The report will outline the likely impact of any visual findings on play, particularly where they might impact upon performance over time, and in specific directions of play. The report will provide a baseline for sports vision performance training, from which to build visual skills. It will also highlight areas of more immediate need, such as inferior skills in one particular area of space, which can then be addressed first, before more general enhancement of visual skills and stamina.