Why so different?

Why is it important to test to the level of function of a professional athlete? Although the vast majority of our patients are not professional athletes, we do see many children and adults who enjoy recreational and competitive athletics. Research has clearly shown that the better an athlete's vision, the better he or she performs. This is especially true at the professional level, but carries down into the college, high school and little league levels as well. Parents want the best for their children and will make every effort to provide them with the necessary tools (e.g. vision and visual efficiency) to perform at their maximum potential in any given sport. In addition, we are all familiar with adults who are true "weekend warriors," giving up their day-job to don sports uniforms on weekends. The market for weekend sports activities is huge, and many of these athletes are keenly interested in doing all that they can to be more successful in their athletic competition. 

For our vision screening system, we use the M&S Smart System, which runs the Professional Sport Vision Tester (PSVT). We have used this system for the last several years because it tests all the performance-based measures used in our vision profile. It is efficient, easy to calibrate and can be operated by a technician. The results of the screening are formatted for direct comparison with our professional baseball player database. The printout provides the performance level on each test along with a color graph of how the test results compare with the major league database. These printouts are very informative for doctor and patient alike.  

Testing athletic vision

Since 1992, we have evaluated close to 2,500 professional athletes. Professional teams such as the LA Dodgers, NY Mets, Boston Red Sox and Los Angeles Kings have participated in screening the four critical areas of vision: visual acuity, contrast sensitivity, distance stereo and dominant eye. We learned a great deal about what differentiates the visual function of an elite professional athlete from the general population. We have developed a professional athlete profile that makes it possible to compare any athlete, professional or not.

Beyond acuity

We use 4-position Landolt rings to record acuities for professional athletes and have gathered measurements ranging from 20/200 to 20/8. This method of testing vision is language and literacy independent and takes all examiner bias and interpretation out of the doctor's hands. The computer runs a predetermined algorithm that increases the test/retest reliability of the measured acuity. The Smart System Pro-Sports screening system records all patient responses and then compares the results with normative baseline data.

The acuities closely follow a normal distribution with 20/8.9 being the best vision recorded to date. There is no significant statistical difference in the vision between the right and left eyes.

The most sensitive test for binocularity is stereopsis. Our unique approach measures distance stereo utilizing both contour stereo and random dot targets. Liquid crystal shutter goggles generate the stereo targets. The disparate target is located in one of four positions on the screen. The subject indicates the correct location of the stereo target by pushing a button on the response pad and the computer records the input for future analysis. As with visual acuity, the computer runs a predetermined algorithm that increases the test/retest reliability of the measured stereo.

Contrast sensitivity testing with and without glare yields important information when assessing the professional athletes' visual capabilities. We use black and white sin wave gratings placed on one of three positions to test contrast. We test low, middle and high spatial frequencies binocularly and again, the computer captures the answers in real time to eliminate any erroneous data. A predetermined algorithm increases the accuracy and efficiency of the test. Professional athletes are statistically significantly more sensitive to contrast at all spatial frequencies than the general population.

From these data, we have been able to derive a vision profile for professional athletes. Our goal now is share this information so vision screening can be done at the college and high school levels. By identifying those athletes who need vision correction early in their career, we can correct it so that poor eyesight will not limit their performance.

Add a sports vision specialty

Now that we have reviewed the visual capabilities of professional athletes and their differences from the general population, we'll discuss specific steps you can take to add sports vision to your practice. What equipment do you need? What are the necessary components of the examination? What is the difference between a vision screening and an examination? What components should be done in the office and what can or should be done "on the field?"

Adding a sports vision specialty is a win-win-win proposition. First and foremost the patient wins (all puns intended). By offering the examinations, implements and therapies that get your patient to perform at their visual best in their sport of choice, you deliver what your patients expect from their eye doctor. If you can provide those services the patient benefits.

Secondly, the doctor wins. We are in a service profession. We are in a unique position as optometrists because we are able to provide both the professional services our patients need and the products that will make their lives better. When a patient comes to the office, they generally have a vision problem. We provide the services and products to solve their problem and in so doing, meet their needs.

The office also wins. When we provide beneficial services for our patients, our reputation grows and with it, so do referrals. A reputation as a sports vision provider (dare we say "expert?") will increase your referral base not only with patients who need sports vision services, but with the rest of their family as well. Sports vision is an excellent practice builder and rejuvenator. It will pump new life into a stagnant practice. It will get you back out into the community dealing with active and young — if not young-at-heart — people.

Special screenings

Vision screening can determine whether a patient is performing above, at, or below a fixed criterion. For example, schools conduct vision screenings to see if children have vision worse than 20/40. If they do, the school recommends a complete examination to determine the exact nature of the problem. A vision screening can be done in the office or "on the field." To conduct sports vision screenings outside the office, you need equipment that is portable and easy to set up and use. We use the Professional Sports Vision Tester (PSVT) to screen all of our athletes both in and out of the office. It clearly delineates in the patient's mind the difference between a screening and a comprehensive examination. The tester has all the components necessary to do a through sports vision screening (see chart below). It is actually the exact same equipment we us to screen the professional baseball players during spring training each year. 

The testing is fully computerized and takes about 10-12 minutes per player. The players' answers flow to the computer via a button pad. You can test yourself, or delegate to a technician with ten minutes of training. We are always on site during the screenings. We begin the testing and gradually turn it over to the technician so we can focus on educating the players and coaches. It is vitally important that the coaches and trainer understand the information that is being gathered and the importance of vision in optimum sports performance. Take advantage of this education process and marketing. Use parent volunteers to help organize the players and get them off the field and to the vision screening site in an efficient manner. These parent volunteers play a vital role in spreading the word to the players about the benefits of the vision screening.

The PSVT results are electronically transferred to a scoring facility where the data are analyzed and an individual report is sent back for each player. It contains the performance level on each test and a bar graph that rates the players against the major league profile. We then distribute the results to each player or their parents and explain each component. If deficiencies are found, we recommend a comprehensive evaluation from a doctor who understands the needs of athletes. That examination will hopefully determine the nature of the problem and offer the athlete options to fix the problem(s).

Further refining correction

The PSVT results determine the necessity of a comprehensive examination. In addition to the normal components of a comprehensive exam, pay particular attention to the deficiencies found during the screening. Let's focus particular attention on refraction. The guiding principle for refracting athletes is, "Very small refractive errors, especially astigmatism, make big differences in the athletes' vision." When refracting an athlete, do not arbitrarily stop at 20/20; keep refining the refraction to challenge the patient's visual system to perform to 20/12.5 or 20/10. Remember the average professional baseball player has 20/12.5. Even if the refractive error is small, trial frame that Rx. You will be surprised at the number of times that small correction will result in one-half or one line of acuity improvement. Additionally, athletes may comment on how much clearer their vision is with the small amount of correction. Prescribe it! 

Small amounts of central suppression often reduce stereopsis at distance. Correcting small refractive errors and small anisometropias can often break down small amounts of central suppression. Orthoptic eye exercises may also result in improved stereopsis. Prescribe them!

Optimal correction can improve below-expected contrast sensitivity. This is especially true if contrast sensitivity is low in the high spatial frequencies. Colored filters can also enhance contrast sensitivity depending on lighting conditions. Prescribe them!

Our focus on Sports Vision will continue next month, with details on how to further refine athletic correction and how to market your new specialty.

Dr. Kirschen received his O.D. and Ph.D. degrees from the University of California at Berkeley. He is currently the Chief of Binocular Vision and Orthoptic Services at the Jules Stein Eye Institute at the David Geffen School of Medicine, UCLA. He also serves as Full Professor of Basic and Visual Science and Optometry at SCCO.

Dr. Laby received his medical degree from the George Washington University School of Medicine. He serves as Assistant Clinical Professor of Ophthalmology at Harvard Medical School and has served as staff ophthalmologist for several professional sports teams including the LA Dodgers, Boston Red Sox, NY Mets and LA Kings, among others. He is the co-author of Dictionary of Ophthalmology.