Does the student have difficulty tracking a ball, aiming at a target, throwing at a target. Are they challenged laterally and moving forwards and backwards? Is balance and gait an area of concern? Do you know if balance and gait is an issue affecting performance? Is your student performing at his/her athletic potential?
Vision is probably the most critical variable in sports today. Athletes must observe rapid movements and react quickly. This is known as placing a load on the visual system. The eyes send information to the brain where it is received and processed as a three-dimensional image. The integration of visual information from both eyes into a 3D image is called fusion. There must be a conscious effort to attend to the critical image otherwise the eyes will continuously move throughout the visual field. Focusing on the object, we must stop and this is called a fixation.
Eye (Sighting) Dominance
The Visagraph indicates which eye is dominant. We all have a dominant eye. The dominant eye transmits the visual image faster than the non-dominant eye. The dominant eye also directs the movement and fixations of the other eye. The Visagraph will also indicate how many times in a visual sequence one eye moves before the other eye. Sometimes, the brain may confuse (process differently) or distort images when the start time differences are significant in number or duration. For example, in baseball, it is important that the head position of the batter permits both eyes to clearly view the approaching ball.
The Visagraph gives saccadic data as to how much information is absorbed in one eye movement. The more information that is absorbed in one eye movement tells us that efficiency of the brain to process the images presented. Saccadic eye movements are used for rapid scanning. Vergence eye movements allow the eyes to focus on objects at various distances. Saccadic movements should be smooth pursuits. If an athlete has inferior saccades and the pursuits are not smooth, his/her performance will be affected.
Visual Accuracy: Acuity, Contrast Sensitivity, Color
Visual acuity is the ability to discriminate in detail an object such as a ball. The Snellen Chart is what most eye specialists use. Other determinants that affect acuity are: including contrast, lighting, motion, time, color, age, and attention demands. Lighting appears to be a critical factor. Ballplayers play in different lighting conditions and so testing must take this into consideration. Greater illumination improves acuity. Too much light may interfere with acuity.
Contrast sensitivity measures the visual system's ability to process or filter spatial and temporal information about objects and their backgrounds under varying lighting conditions. If an athlete has excellent contrast sensitivity, he/she will be able to discriminate favorably as the ball increases in velocity. For best performance, coaches should make sure that playing/practice areas are well-lighted and the background areas contrast sharply with the ball, hoop, etc.
How an athlete perceives color affects acuity. Some athletes have difficulty discriminating between red and green, or between blue and yellow. Coaches may need to adjust the environment in order to increase the athlete’s performance.
Baseball players, for example, should know that vision will be most precise in observing motion at right angles to the line of sight. Visual recognition of motion away or toward your direction of vision (an inside or outside pitch in baseball) will be less accurate than across the mid-line of the body.
The Visagraph indicates saccadic movement and tracking. It is critical for athletes to have their eyes travel from an extreme left to an extreme right without moving the head such as in batting or hitting a tennis ball. If the head moves like a typewriter in order to track a ball, it demonstrates limited range and inefficiency.
The Visagraph will provide a myriad of data that will inform as to the how the brain and eyes work together. This information is evaluated and shared with Dr. Spurling who will continue the assessment.
Dr. Spurling will perform a Neuro Optometric rehabilitation evaluation which will provide information regarding the profound relationship of the visual process to balance, posture, movement, position sense, cognitive processing and memory. Her testing may include: refraction, sensorimotor, and a visual evoked potential (VEP) examination. The VEP will present information about the quality of the perceived image that travels from the eyes along pathways to the brain. The testing may indicate traumatic brain injury. After a baseline is determined, the correction process is initiated.
Further treatment of identified issues may take place using corrective lenses and visual therapy exercises.
Reference Article: From eye movements to actions: how batsmen hit the ball