“Vision is the trigger mechanism controlling the athlete’s first move.” – Martin WF: What the coach should know about the vision of athletes
“If an athlete is not visually fit, he is certainly not physically fit.” – Garner AI: Visual aid prescribing for the athlete
The two statements above were reiterated in a must-read article titled “Overview of Research Information Regarding Vision and Sports” by Arnold Sherman O.D. The article highlights the necessity of having an array of visual skills for optimal athletic performance, including “visual acuity, especially dynamic acuity, depth perception, stereopsis, accurate triangulation, eye movement accuracy and speed, peripheral vision and visualization.”
Let’s start with visual acuity
It’s not just about seeing 20/20 or even 20/15 on a stationary snellen chart; what really matters is how the athlete sees while the target is moving, hence dynamic acuity. This is critical because it mimics real-life scenarios, especially in high-speed sports (i.e. baseball, tennis, and hockey) where athletes need to recognize the target quickly. If dynamic acuity is reduced relative to static acuities, particularly with the incorporation of head or body movement to follow the letters, you know the athlete is a little bit on the trouble side!
As for binocularity
The eyes must form a perfect triangle with the fixation target without assuming an over-convergence (eso) or under-convergence (exo) posture. Otherwise, the baseball batter may hit the ball sooner if esophoric due to seeing things closer, and vice versa if exophoric. Ocular alignment must be assessed in all positions, primarily in the playing position, to reveal any fusion difficulty, diplopia or suppression. For example, Brock string is to be performed in both the normal and batting stance when assessing a baseball batter. Furthermore, the athlete must maintain fusion of the moving target at all distances for accurate perception of depth and judgment of relative distances. These factors allow the athlete to determine the relationship between the target, the surrounding environment and him, which in turn heavily influence his next move.
Oculomotor (eye-movement) skills
Pursuits and saccades are critical for accurately and rapidly tracking a moving target. An athlete performs better when these eye movements occur alone in the absence of associated head or body movements.
Peripheral vision and visualization are also key elements in sports
Peripheral vision is used to gather as much information as possible about the surrounding environment, whereas visualization helps an athlete think beforehand and mentally devise a plan-of-action built from previous experiences to enhance future performance.
Finally, an athlete’s general ocular health is important
This includes examining both the anterior and posterior structures of the eye, as well as the integrity of the visual pathway to and from the brain.
So on that note… Let me tell you about the East Coast Pro Showcase held at the Syracuse Chiefs’ Alliance Bank Stadium. Two doctors, one resident, and six students from SUNY College of Optometry had the opportunity to participate in this non-profit event run by Major League Baseball (MLB) scouts. It is designed to evaluate the best 150 high school baseball players selected by scouts from the East Coast. Our role was to assess these players’ visual skills and provide the analyzed data to the MLB Scouting Bureau.
We arrived bright and early on Thursday, August 2nd 2012 at the stadium and set up several stations to test the visual skills of the athletes. This included acuity (static, dynamic with the Sherman Disc), focusing speed and accuracy (-1.50 flipper with far test chart), binocularity (NPC, Worth 4 Dot, cover test at distance and near, stereopsis, Brock string, phorias), oculomotor (pursuits, saccades), recognition accuracy and speed (tachistoscope), eye-hand coordination (Wayne Saccadic Fixator – WSF), and general ocular health (pupils, posterior pole).
Players travelled between stations and lingered occasionally to either encourage or competitively assess other players. The most competitive stations were the dynamic visual acuity and WSF. The most enjoyable station appeared to be the WSF, where pro-action time, reaction time and hand speed were recorded. Observations to note while performing the WSF included behavior (calm vs. flustered) and the athlete’s head and body position, which ideally should be stationary as he uses his peripheral vision to locate the next flashing target and respond with an accurate saccade.
The screening took place over two days. One of our goals was to educate the athletes and scouts that vision skills are more than 20/20 eyesight. Vision is a process integrating the eyes that receive the information, the brain that processes it, and the body that carries out the action. Since an athlete’s actions are influenced by what he sees, it’s important to realize that these visual skills can be modified or enhanced via corrective lenses or vision therapy. This consequently provides for efficient processing and stronger athletic performance.
In conclusion, despite all the hard work, we enjoyed watching baseball games while simultaneously observing scouts perform their keen job. We also chit-chatted the first night away over a wonderful three-hour dinner at the Genesee Grande Hotel accompanied by Dr. Sherman and Dr. Byne’s lovely wives, Jill and Marti. Needless to say, it turned out to be an enjoyable and educational event, which makes up for our resulting crouched spine from ophthalmoscope and scratched voices from continuously re-assuring players that they all performed better than the other!
The University Eye Center (UEC) at SUNY College of Optometry opened its new Sports Vision Center which is designed to evaluate athletes’ visual skills and provide any necessary training to enrich performance. The center is directed by Dr. Sherman, who was in charge of the Syracuse screening event (on behalf of the UEC) with the coordinated help of Tim Osborne from the MLB Scouting Bureau.
For a good description on some of the above screening tests as well as a list of sports that have corresponding high, medium or low demands for certain visual skills, I recommend the following references:
- Gardner JJ, Sherman A: Vision requirements in sport. In Loran DFC, MacEwen CI, editors: Sports vision, Oxford, 1995, Butterworth-Heinemann.
- Sherman, A.(1980) Overview of research information regarding vision and sports. Journal of the American Optometric Association, 51, 659-65.
- Sherman, A. (1990) Sports vision testing and enhancement: implications for winter sports. In Wintersports Medicine (ed. Casey, Foster and Hixson), F.A. Davis, Philadelphia.