Figure 1. Accurate and timely delivery of visual information is crucial for performance in all sports.
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The practice specialty of sports vision has evolved into a diverse application of optometric, psychological, and medical skills. Not surprisingly, there are relatively few practitioners who have the backgrounds that allow them to offer a full range of sports vision services to athletes.
This course will describe some of the requirements for working with athletes and will provide an overview of ways in which the sports vision specialist can enhance the performance of his or her athlete patients.
Sports vision services typically include:
The basic premise of sports vision is that the eyes feed information to the brain, which interprets it and then activates the arms, hands, legs, feet, and balance system. This happens within a fraction of a second, over and over again for the duration of the game. When the eye’s message is inaccurate, incomplete, or not delivered at the correct time, performance can suffer.
Figure 1. Accurate and timely delivery of visual information is crucial for performance in all sports.
Many people call themselves sports vision specialists, which can mean as little as fitting contact lenses or providing protective eyewear for athletes, or it can mean that the doctor provides a comprehensive sports vision analysis along with vision enhancement training. The important thing is that sports vision specialists have the common goal of helping athletes to maximize their potentials and perhaps gain the elusive competitive edge.
There are some personal responsibilities for a doctor who provides sports vision services:
Sports vision specialists evaluate the following areas:
As a sports vision provider, you need to have knowledge of all available treatment options, and you need to stay current on changes in technology to help the athlete excel.
If you want to add sports vision services to your practice, you need to identify the top participation sports in your area, and then find ways to market your services to potential patients who participate in these sports. Speak to runner’s clubs, the YMCA, the YWCA, fitness clubs, little league coaches' conferences, pistol shooting organizations, golfers' meetings, etc. It’s limitless to whom you can speak regarding the services you have to offer.
What are the time and space requirements needed to practice sports vision? Many sports-related tests can be done right in the exam room. They don’t have to take very much time or require special equipment, but they can provide very valuable information. Something as simple as a Brock string, dominant eye determination, or Maddox rod phoria assessment can be done in a matter of minutes right in the exam room.
Other tests require a little bit more space and may have to be done in another room such as a vision therapy room or a room specifically set aside for sports vision. Some doctors have very limited space but others have access to a large gym-type facility where all of the equipment is set up so the athlete can move from one station to the next. This is ideal, but not necessary to practice sports vision.
If a large room is available, then a careful plan is required as to where all of the equipment should go. Floor space for walking rails and balance boards, and wall space for instruments and testing equipment should be considered when planning a sports vision room.
Figure 2. Typical sports vision testing/training room.
When sports vision testing is carried out at a location away from the clinic, e.g., on the practice field on in a gymnasium, it is necessary to adapt testing equipment to the space allotted. Testing in strange places, such as the visiting team locker or shower room is relatively common. Things should be planned so that there is a smooth flow from one test to the next, with adequate lighting and clear markings as to where the athlete should stand during testing.
The amount of money required to establish a sports vision practice can be as little as a few hundred dollars to get some basic vision therapy equipment for testing general skills, or it can be thousands of dollars to purchase high tech equipment that will provide detailed information about the athlete's visual skills. (A list of equipment suppliers is provided as Appendix 1.)
Table 1. Minimum equipment required for a sports vision practice.
Table 2. A more extensive (and expensive) battery of sports vision testing and training equipment.
There are many instruments that can be used in a sports vision work-up that do not necessarily have to be sophisticated or expensive. A handful of simple tests using very inexpensive equipment can reveal significant information regarding how an athlete’s eyes are affecting his or her performance. If further information regarding the role of visual skills on the playing field is required, specialized sports vision equipment can be purchased or the athlete can be referred to a clinic where more equipment is available.
The battery of tests provided for an athlete should relate to the sport in which the he or she participates and the individual needs/concerns of the athlete. Athletes are highly goal-oriented, therefore the instruments should be as closely related to the sport as possible. Existing instruments can be adapted to meet the needs of each sport. The most effective testing should be performed in free space and in the athlete’s particular position (e.g., in the crouch position for a hockey goalie).
When undertaking a sports vision evaluation, an explanation should be given regarding the test being done and how it relates to the particular sport. This will help the test to make sense to both the athlete and the coach, and it will help to ensure maximum performance output from the athlete being tested.
How do you learn to use the sports vision equipment you have acquired and further your knowledge in the area of sports vision?
Sports vision evaluations can be provided either in the form of screenings or complete examinations. Although there can be a considerable overlap between these two modes of care delivery, they will be discussed separately.
Holding a sports vision screening is one of the best ways of letting people know what a sports vision practice can offer.
Who should you contact to set up a screening?
Sometimes the hardest part of testing a team is convincing the coach regarding the importance of what you have to offer. Coaches tend to want to know everything and may be leery because they don’t know how sports vision fits in to their programs.
It would be very beneficial if you can run the coach or trainer through the sports vision work-up first. If this is not possible, then bring some hands-on equipment with you when meeting with them.
You must also relate to the specifics of the sport to the particular visual demands associated with it. For example, an archer should not be trained in peripheral awareness. Instead concentration and visualization should be emphasized.
Some other things to consider:
Sports vision screenings can be done in one of two ways: in the office or on location in the field.
In the Office
In the office, stations can be set up and staff members will be available to assist in testing. In this situation, to minimize confusion and maintain a smooth flow, we generally run 3 athletes at a time through the different testing stations.
Advantages of in-office screening include:
Figure 4. Office setting where screenings can be done.
Screenings On-Location in the Field
Sports vision screenings can also be done on-site at locations such as the school gym, playing field, or locker room. This may be more convenient for the team to fit it into its schedule. It also shows the coach or trainer that you take the screening seriously and that you are flexible and willing to accommodate the team within your practice’s busy schedule.
An advantage of screening on location is that other people in the area, such as parents, secretaries, administrative staff, etc., can see what is being done and may take an interest in your services.
However, there are also problems associated with screenings away from your office. For example, you will probably have to be more flexible in the order of testing players. What generally happens is that a group of athletes comes by between their practice sessions or drills for testing. There may be time spent just waiting around for the players to come, but once they arrive, you must be ready to go and get them through quickly so that they can quickly return to their practice. Another disadvantage of on-site testing is that not all of the equipment can be taken along, so there might be slightly less in-depth testing provided. However, athletes who have significant problems detected during a screening can be referred to your office for more extensive evaluation.
Figure 5. Evaluating athletes on location can be very useful.
When the screening project is over and the results have been analyzed, prepare a straight-forwarded, easy to understand report for the coach and trainer. Have explanations for each testing area and how it relates to the specifics of the particular sport. Describe those players who have particular strengths and weaknesses. Then make realistic recommendations that the coach, trainer, parents - and particularly the athlete – can understand. It may is necessary and desirable to make somewhat different reports and recommendations to coaches, trainers, athletes, and parents. Allowing the coach or trainer to interpret screening results to athletes and parents can often be a good plan if the coach or trainer really understands what your screening has revealed.
To begin a complete sports vision examination, use of a history and symptom questionnaire is recommended (See Appendix 2). An athlete, especially if he or she is young, may not associate mediocre athletic performance with a vision problem and may not spontaneously report the problem to an eye doctor. Unless an adequate history is taken, we may not be aware that a potential problem exists and may lose the opportunity to investigate various components of vision that could reduce performance.
After reviewing the history questionnaire, we generally ask more questions regarding the athlete’s past and present visual health, use of eyewear or contact lenses, and visual status during athletic competition. This gives us an understanding of whether the athlete is aware of any problems and whether he or she feels that problems might be affecting performance.
If the remainder of the examination reveals that the athlete has a visual problem but is unaware of it (or has developed compensations for it), this will determine how we deal with the problem. If, on the other hand, there is a problem and the athlete is motivated to do something about it, this increases the probability of a successful remediation.
As sports vision practitioners, we need to evaluate the health of our athlete patients' eyes with special care because of the possibility of past trauma. In making these evaluations, we may become aware of certain medical conditions that can affect performance. We also need to keep in mind that athletes are subject to the same diseases and anomalies as are non-athletes.
Some of the tests to be done in evaluating eye health can include:
Glaucoma test. Ideally, Goldmann tonometry should be done, but the Tonopen® and other devices provide a good alternative for measurement of intraocular pressure (IOP).
Visual field testing is also important for athletes. If done out of the office, the Humphrey/Welch Allyn Frequency Doubling instrument is portable and gives reliable data. It is important to note any blind spots that the athlete may be unaware of. If they are stable and benign, the athlete can compensate for them and/or the coach can position the athlete so as to reduce the need to see in the area of the blind spot.
Retinal evaluation is of great importance for athletes. A good look at the optic nerve and posterior pole can be obtained with a direct ophthalmoscope. This device is very portable and can be taken with you to an on-site screening.
Ideally, the entire retina should be evaluated and documented photographically. However, retinal cameras are too large and expensive to take on screenings and complete evaluations of the retina with a binocular indirect ophthalmoscope require pupil dilation. These procedures require office visits but are nevertheless important. Often when examining athletes, they will decline dilation because they have other health physicals to do and may have sports practice later in the day.
A newer device is available for retinal evaluation without the need for dilation. It is called the Panoramic200 and provides an image called an Optomap (Optos, Inc.). The instrument provides a 200-degree field of view including the peripheral retina.
The Optomap takes only a few minutes and provides a relatively thorough evaluation of retina. Some of its advantages include:
Figure 6. Optomap instrument.
Accurate assessment of visual acuity is of utmost importance for athlete patients. There are three types of acuity that are typically assessed: static, dynamic, and contrast sensitivity.
Static acuity. Static acuity is the ability to see a non-moving target at a fixed distance. If it is worn for their sport, players must be tested with their full correction in place.
Some examples of sports that require high levels of static visual acuity include pistol and rifle shooting, and archery. Basketball players have a medium demand for high static acuity, and football linemen have a relatively low demand for good static acuity because opposing players are relatively large and slow moving.
Static acuity is typically tested with a Snellen eye chart. (Figure 7)
Figure 7. Snellen acuity chart.
Dynamic visual acuity (DVA) involves the ability to detect detail when there is relative movement between the player and the object. It is used when the athlete and/or an object (ball or puck) are in motion, and it generally involves binocular vision. A player with good DVA is able to move his or her eyes, rather than the head or body, to follow the action.
Dynamic visual acuity can be tested with a Kirschner rotator, which is an oculorotor device utilizing a Snellen chart projected onto a rotating mirror. Some doctors also test DVA using a dynamic acuity disc that can be purchased from Bernell, Inc. The disc is put it on a standard record player turntable and can test acuity at various speeds. The large letters on the disc are 10/30 (3/9) and small ones are 10/15 (3/4.5). DVA can be measured at 78, 45, and 33 rpm.
Figure 8. Dynamic acuity test device.
Sports that require high dynamic acuity include baseball, tennis, and hockey (especially the goalie position). Sports with a medium DVA demand include basketball and soccer, and golf has a low demand.
Refractive Error Determination
Refractive errors for athletes are measured just as they are for non-athlete patients. Typically an autorefractor measurement or retinoscopy is followed by a subjective refraction. Special care should be used to ensure an accurate determination of cylinder power and axis. In the case of a hyperopic patient, a cycloplegic refraction should be considered.
Contrast sensitivity is the ability to see light against dark or differentiate between different contrast levels. Some feel that this measurement gives a more realistic assessment of sports-related acuity. Contrast sensitivity can be tested using plates, wall charts or electronic devices.
Figure 9. Contrast sensitivity test device.
Contrast sensitivity is important for the golfer who has to read the green in different lighting conditions and the outfielder who must be able to see the white ball against the blue sky (or in the dirt).
Eye Tracking/Oculomotor Skill Assessment
These skills are definitely important for the athlete who needs to track the ball with strong pursuit movements or have good eye saccadic (rapid movement) skills.
There are various ways to assess tracking and eye movement abilities. These include:
The projected King-Devick, which is available from Bernell, Inc, consists of 3 charts printed on clear acetate. Charts are projected at a distance of 10 feet (3 meters) with an overhead projector. The athlete stands and must call out the letters, from left to right, as quickly as possible without making errors. The time and errors are recorded on each of 3 sub-tests as well as the overall time for all the tests. The examiner should note any head movements made when taking the test because they indicate that the athlete is having a problem moving his or her eyes.
Figure 10. King-Devick test sheets.
Accommodation involves changing focus from near to far and vice versa. The ability to repeatedly cycle accommodation is very important in many sports.
Flippers Accommodative ability can be tested in a number of ways. Using plus and minus 2.00 diopter lenses flippers, the athlete can be asked to repeatedly increase and release two diopters accommodation. The number of cycles per minute provides an indication of accommodative ability. We test both binocularly and monocularly at 40 cm with a reduced 20/25 (6/7.5) line of letters.
Figure 11. Testing accommodation with plus and minus 2.00 diopter flippers.
Hart Chart Accommodation can also be assessed using a Hart Chart distance rock test (available from Bernell, Inc.). It utilizes 20/80 (6/24) distance letters and 20/25 (6/7.5) near letters. The athlete is asked to call out the first letter on the distance chart and then refocuses to the first letter on the near chart. He or she then focuses back to the second letter on the distance chart then back to the second letter on the near chart, and so forth. The examiner counts the number of correct cycles completed in 30 seconds.
Figure 12. Near and Far Hart charts. This example simulates the athlete focused on the distance chart so the near chart is out of focus.
Saccadic Fixator The Wayne Saccadic Fixator also has an accommodative rock panel that helps evaluate an athlete’s focusing skills.
Although assessing binocular vision is a customary part of a general eye exam, specialized evaluation of the athlete requires objective and subjective testing of fusion and suppression in various positions of gaze.
Cover test This test is done at both at distance and near with the athlete’s optical correction in place. A target of reasonable acuity demand should be used. The athlete is tested while standing and in all positions of gaze. Any strabismus and the amount of heterophoria are recorded.
The Brock string is used to assess the eyes' alignment in space. It is a very simple test and can detect suppression as well as measure ocular alignment accuracy. Standard testing is done at 16 inches (40 cm), 3 feet (1 meter), and 10 feet (3 meters) in all positions of gaze. It can also be used to simulate the athlete’s primary position of gaze (e.g., at the end of a basketball hoop or down low simulating a hockey stance).
Figure 13. Use of a Brock string.
Maddox rod phoria testing provides an objective assessment of an athlete’s phoria. The Maddox rod is held over one eye and the athlete is asked to look at a penlight held behind a muscle alignment card. The athlete identifies where the red line crosses the white test light by reading the number on the card. This should be done both horizontally and vertically. The test distance and position of the test light can be varied to imitate the conditions of the athlete’s sports (e.g., up on the rim of a basketball hoop).
Figure 14. Binocular vision testing using a Maddox rod.
Most sports require good depth perception, which can be tested in a number of ways. Tests for stereopsis typically use polarizing or red-green anaglyphic materials, which allow disparate images to be viewed. Stereo acuity is typically is expressed in seconds of arc. The design of most stereo tests requires that they be done at 16 inches (40 cm). However, most athletic events require stereopsis beyond this distance.
The following equipment can be used to assess distance stereopsis:
American Optical Vectographic Slide: Wirt Circles The athlete is positioned 10 feet (3 meters) from a screen on which the slide is projected. The room is darkened and the athlete wears polarizing glasses, which separate the images seen by the two eyes.
The slide projects 4 rows of 5 circles. On each row, one circle is projected with crossed disparities ranging from 240 to 60 arc seconds. This causes the image of the circle to appear closer to the athlete when viewed through the polarizing lenses. Each row is presented separately, and the athlete is asked to identify the circle that stands out. The time required to respond for each row and minimum disparity that produces the stereo effect are recorded.
Figure 15. Wirt Circles. The slightly darker circles on each line simulate the ones that would appear to stand out.
Howard Dolman apparatus tests distance stereopsis by asking the athlete to align two rods using only retinal disparity cues. The accuracy of repeated settings is recorded.
Figure 16. Howard Dolman apparatus. The athlete aligns the two black rods in the horizontal plane by pulling on strings attached to them.
BVAT The Mentor BVAT is an electronic device that presents stimuli on a video screen. It evaluates stereopsis at 10 feet (3 meters) or more and has been modified to make it portable for on-site testing.
Examples of sports requiring a high degree of distance stereopsis include golf, baseball, hockey, and soccer. Basketball requires a medium degree of stereopsis, and wrestling and weight lifting have a low stereopsis demand.
Testing of vergence ranges is generally performed through a phoropter. Ideally we want to evaluate vergences in free space so vectograms/tranaglyphs are projected at a 10 foot (3 meter) distance using an overhead projector. Near vergences can also be measured using targets placed at 16 inches (40 cm).
Figure 17. Near tranaglyphs with red-green separations used to assess and train near vergences.
Peripheral Awareness Assessment
Many sports require highly developed peripheral awareness skills. Some examples include baseball pitchers who must be aware of runners at first base, football quarterbacks who must be aware of oncoming tacklers, and hockey goalies who must be simultaneously aware of the positions of opposing players and the puck.
Peripheral awareness can be assessed with the Peripheral Awareness Trainer (available from Wayne Engineering, Inc.). This device tests peripheral recognition of stimuli and response times for eight different visual field locations. The trainer is mounted at eye level on the wall and the athlete is instructed to always fixate a center spot on the device. (Eye alignment is very important to maintain accuracy.)
In dim illumination and at an arms length distance, the athlete watches the central fixation light and moves a joystick as fast as possible in the direction of stimulus lights that appear in the periphery. Each stimulus light is presented from 2 to 5 seconds, and the time required to respond is measured in hundredths of a second. Two trials are done and the average response per stimuli is calculated.
Figure 18. Peripheral Awareness Trainer. Stimulus lights are presented on the tips of the rods.
The Acuvision and Wayne Saccadic Fixator devices also have programs to test peripheral awareness/reflexes. Use of these devices for testing and training will be discussed later in the course.
Figure 19. Wayne Saccadic Fixator and Acuvision device.
Speed of Recognition Measurement
Speed of recognition is the ability to take in a significant amount of visual information, process it in the brain, and then have the body react to it by moving a certain way. The speed with which an athlete can recognize an object is very important in many sports. Rapid recognition will make the athlete's performance quicker, more accurate, and more efficient.
Speed of recognition can be tested and trained using a tachistoscope, which is a projector that can be used to flash a series of numbers, symbols, or pictures on a screen for brief periods. The athlete must identify the stimulus presented in the brief flash and/or react in a certain way to it.
Figure 20. Tachistoscope projector.
In our office, tachistoscopic testing is done by projecting three rows of 5 numbers on a screen for 1/100 of a second. During testing, the athlete stands 10 feet (3 meters) from the screen and is instructed to pay attention to one of the rows and call out the numbers that are projected.
The scoring system is as follows:
For training this skill, sports scenes can be presented instead of numbers and the athlete is asked to identify certain details in the scenes (e.g., an aspect of a baseball pitch).
Also for training purposes, the following can be done:
Eye-Hand Coordination Assessment
In certain sports such as baseball or hockey, objects move at speeds of over 100 miles per hour (160 km per hour), so it is critical for the athlete to coordinate the timing of his or her body to hit a ball or puck at the appropriate point in space.
A number of instruments have been developed to test this skill:
Wayne Saccadic Fixator This device measures the time required to make a motor response to a visual stimulus (see Figure 19). The Wayne device is a flat panel mounted on the wall at eye level. The athlete stands at arm's length and fixates on a central spot. Stimuli are then presented in the periphery. These stimuli consist of buttons that can be lighted and must be pressed with the hand as soon as possible when they are illuminated.
There are two main test modes:
During testing, the examiner should observe:
Figure 21. Wayne Saccadic Fixator. This device has letters attached to the peripheral buttons so that it can be used for additional tests.
Acuvision This device is somewhat similar to the Wayne Saccadic Fixator. It is presently is not commercially available, but it can be found in the used marketplace. It consists of a computer-controlled grid of 120 touch sensitive lights mounted on a wall panel.
Under dim illumination the athlete stands facing the panel, which is at arms length, and fixates the central light. Peripheral lights are presented at random using one of 11 different speeds, and the athlete is required to press each light as soon as it illuminated. The test time is 60 seconds.
Acuvision prints out a graph representing performance in six zones of the grid: upper left, upper middle, upper right, lower left, lower middle, and lower right. It shows whether the athlete responded accurately within the first 70% of the time that the lights were illuminated. It also gives a numeric score for the number of late responses for each of the six zones.
Figure 22. Acuvision instrument.
Sports Vision Trainer (SVT) (made by Sports Tec) This instrument was designed by Pierre Elmurr, from the University of Sydney in Australia. This is an eye-hand coordination assessment and training device that consists of a light board with 80 circular lights that are controlled by a computer.
The athlete stands in front of the light board and reacts to lights that are illuminated, either in random or pre-programmed sequences. Similar to the Wayne Saccadic Fixator, proaction and reaction scores are measured. Results are recorded by the computer program and can be exported to Microsoft Excel for further analysis.
Figure 23. SVT instrument.
The following are differences between the SVT, Wayne Saccadic Fixator, and the Acuvison device:
Anticipation Timing Measurement
The Bassin Anticipation Timer (available from Lafayette Electronics) and the Speed Track (available from Wayne Engineering) test the ability to anticipate when a fast moving object will reach a certain point in space. This is an important skill in games like baseball in which fast moving balls must be hit or caught.
These instruments consist of a series of tracks that can be fitted together to form a runway series of lights. Sequentially illuminated light emitting diodes simulate the movement of an object coming toward the athlete. The examiner can set the speed to re-create the speed of the particular sport (e.g., a 90 mph baseball fastball).
The athlete must swing a bat, hockey stick, or tennis racket at a time when they anticipate the light sequence will cross the end of the runway. Two practice runs are given and then five testing sequences are provided. The mean response in milliseconds is recorded along with whether the athlete swung early or late.
Figure 24. The Bassin Anticipation Timer.
Eye/Body Coordination Assessment
The Wayne Saccadic Fixator comes with a balance board that allows measurement of this skill. The board is placed 10 feet (3 meters) from the wall-mounted Wayne unit. The athlete stands on the board and moves it in the direction of the light presented on the saccadic fixator board. Lights can be presented at 3, 6, 9, and 12 o’clock. The proaction setting is set for 30 seconds.
Athletes participating in the following sports will benefit from testing with this instrument: skiing, soccer, basketball, hockey, and figure skating. All of these sports require rapid and efficient shifting of balance using the legs and feet.
Figure 25. Balance board testing using the Wayne Saccadic Fixator.
This skill can be measured by using the Reaction Movement Timer (available from Lafayette Instruments). Similar measurements can be also be made with the Wayne Saccadic Fixator.
This test measures the athlete’s speed of reaction and response to a visual stimulus. The Reaction Movement Timer consists of two units: a control console and a test unit that contains two buttons: the reaction button and the response button. The athlete depresses the reaction button with the palm of the dominant hand. A warning light is then presented to signal that a target light will be illuminated in the next 2 to 4 seconds. When the target light is illuminated, the athlete is required to release the reaction button and to depress the response button. Two practice runs are given and then the reaction speeds for 5 trials are measured.
Two measurements are made by this device:
An athlete can have slow reaction and response times, or one time can be slow with the other time normal.
Figure 26. Reaction Movement Timer.
It is obviously important to identify team members and/or opponents during a game. Jersey color can help determine which team a player is on, so it is advantageous for the athlete to have good color vision. A number of color vision tests are available; two commonly used ones are the AO Pseudoisochromatic plates and the Ishihara plates.
For athletes who do not have normal color vision, specially tinted contact lenses are reported to help with color discrimination (but they do not correct the underlying genetic color vision deficiency experienced by approximately 10% of males). These contacts are called Soft Chrome Lenses and come in both gas permeable and soft versions. The lenses aren’t always effective because color perception is very subjective and because athletes can have varying degrees of color vision loss.
Night Vision/Glare Recovery Assessment
Good night vision and quick glare recovery can improve an athlete’s overall performance, especially for night games played under artificial lights. One of the instruments commonly used to assess night vision and glare recovery is the American Automobile Association’s Night Sight Meter. This unit gives data on night vision, glare vision, and glare recovery time.
Figure 27. American Automobile Association’s Night Sight Meter.
Visual Concentration Assessment
Many athletes complain of being visually distracted when playing their sports. People moving around in the stands (e.g., fans sitting behind the basketball backboard and waving or swaying to distract free-throw shooters) or wearing bright colored clothing can easily distract them. An athlete’s level of concentration is critical to successful performance.
A technique that is very effective in testing the ability to deal with this problem and in training the athlete to reduce the effects of "visual noise" utilizes a strobe light. The athlete is asked to perform their sport while a strobe light flashes in the background. This visual noise causes a distraction, which forces the athlete to perform at a higher level in an attempt to compensate for the distracting light flashes.
The goal in training is to raise the threshold of visual concentration to allow the athlete to cope with distractions that hinder his or her performance. After doing this exercise with the strobe for about 10 to 15 minutes, the athlete then goes out onto the playing field or basketball court to continue practicing. Following training, many athletes report that they are able to concentrate better and are less bothered by peripheral distractions.
Some athletes have commented that after using the strobe light, the ball appears to slow down and seems larger.
It should be noted that anyone with the tendency to have seizures (e.g., epilepsy) should not use this technique because the strobe could trigger a seizure.
Strobe lights can be purchased at many electronics stores (e.g., Radio Shack). An on the field strobe device called Strobe Specs has also been developed. Although it is no longer being manufactured, a used one can be usually found in the marketplace.
Figure 28. Strobe light and Strobe Specs.
Cover test, Maddox rod, Worth 4 dot, and Brock string tests will generally show an eye muscle alignment pattern of eso or exophoria. Athletes with esophoric eye posture tend to undershoot the putt or hit the front of the rim in basketball. They see the world closer to them than it really is.
Those with an exophoric posture tend to see the world a little further away than it really is and tend to overshoot their targets.
Both of these conditions give the athlete a different visual message and he or she reacts accordingly. Targets are seen at a different location in space than they really are, and the athlete's sports performance may be a reflection of this.
There is considerable interest in the professional literature concerning the association between an athlete's dominant eye, hand, foot, and his or her performance. There are various theories relating to the significance and effects of the various types of ocular dominance.
Potential applications of these theories are interesting. For example, one researcher has reported that the dominant eye sends a signal to the brain 14 milliseconds faster than the non-dominant eye. There are no studies that validate the significance of this finding with respect to athletes, but preliminary data show that there may be some correlation between dominance and sports performance. This requires further investigation.
The most common method used to determine eye dominance involves assessing sighting eye preference. The athlete is asked to fixate a distance target, such as a 20/40 (6/12) letter. He or she is then asked to hold a tube or a card with an aperture held at arm's length. One eye is closed or covered at a time, and the athlete is asked if he or she can still see the target. The eye that can still see the target is the dominant/sighting eye.
If the sighting eye and dominant hand are on the same side, it is called matched dominance. If they are not, it is called crossed dominance. Researchers measuring the effects of matched and crossed dominance in various sports have reported conflicting results. For shooting sports, eye dominance is more important than hand dominance. So, even though there may be some controversy in this area, checking for dominance is useful and should be done in any sports vision workup.
We need to offer athletes adequate eye protection for their particular sports. However, not all sports have the same risks of ocular trauma so the sports vision specialist needs to know which sports have a high risk and what ophthalmic materials are available to help reduce risk in these sports.
Sports can be classified as placing an athlete at low risk, high risk, or an extremely high risk for an eye injury, but most sports that pose a risk to the eyes can be made quite safe by the use of appropriate protective devices.
The athlete deserves a careful explanation regarding the risks of eye injury when the proposed sport is played with and without eye protection. Glass lenses, ordinary plastic lenses, and open eye guards do not provide adequate protection for those involved in active sports.
Low risk sports do not involve a thrown or hit ball, use of a bat or stick, or aggressive body contact. Examples include track and field, swimming, gymnastics, and rowing.
Sports with a high risk of eye injury involve the use of a high-speed ball or puck, use of a bat or stick, close aggressive play with intentional or unintentional body contact, or a combination of these factors. Examples include hockey (ice, field, and street), racket sports, lacrosse, handball, baseball, basketball, football, soccer, and volleyball. The incidence of eye injury in these sports is of great concern, but adequate eye protection devices are readily available.
Sports that involve an extremely high risk of eye injury include the combat sports such as boxing and full contact karate. Effective devices to protect the eyes are not available for these sports, so injuries are common.
A good way to become known to a local team is to provide a sports vision first aid kit to the trainer or coach. (Appendix 3) Spending time with him or her to demonstrate how to deal with minor ocular injuries could pay big dividends in the form of referrals and screening opportunities.
For sports that do not entail physical contact between athletes, the obligation to prescribe eyewear primarily for its protective function is not a high priority. Rather, prescribing should be on the basis of its capacity to maximize visual acuity, contrast sensitivity, and protection from ultraviolet radiation. Some sports that fall into this category include biking, skiing, mountain climbing, running, and golf.
To prescribe appropriate eyewear, optometrists must be familiar with prevailing standards for protection from ultraviolet radiation, the transmittance characteristics of various ophthalmic lens materials, and the use of tints.
Figure 30. Ultraviolet radiation from the sun can pose a problem for athletes participating in outdoor sports.
Athletes and most people involved with recreational activities are usually outdoors. This puts them at greater risk of incurring ocular damage from the sun. Some of the possible effects of ultraviolet radiation on the eyes include cataracts, pinguecula, pterygium, and photokeratitis.
Athletes who play indoor sports can also be at risk from UV light. The metal halide light bulbs used in many gymnasiums can emit dangerous amounts of UV if the outer casings of the bulbs are broken. Skin and eyes can be damaged by UV radiation from broken bulbs, so the bulbs must be replaced at once if they are defective.
So how do we protect athletes from ocular damage caused by UV light? Typically, protection is provided by the use of lenses that absorb UV before it reached the eyes. For example, most contact lens manufacturers provide materials with some UV protection. (Vistakon actually provides UV protection in their complete line of products.) But contact lenses alone don’t provide adequate protection from UV radiation. Proper sunglasses or goggles are also needed to absorb 95% or more of both UV-A and UV-B, which are the two components of the UV spectrum that are not filtered out by the atmosphere.
Figure 31. Contact lenses can help to absorb unwanted and dangerous UV light.
(For more information on UV risks and protection, consult the Pacific University College of Optometry On-Line CE course titled, "Protecting Patients from Ultraviolet Radiation" by Karl Citek, OD, PhD. The course catalog is available at www.opt.pacificu.edu/ce/)
Athletes with vision or vision-related problems can be treated in a variety of ways depending on the problems they present. The most important first step in treatment is to compensate for any refractive errors so as to maximize acuity. This can be done by the prescription of contact lenses or referral for refractive surgery.
When refractive errors have been compensated or corrected, a specialized course of vision training can also be provided to remediate any other problems the athlete is having.
In considering refractive error compensation options for athletes, we obviously need to have a good understanding of contact lens fitting and how contact lens wear relates to the athlete in his or her particular sport. The athlete must have the best visual acuity possible, and, in my opinion, this is provided by the use of contact lenses.
Acuity demands are obvious in sports such as tennis and baseball in which it is critical to immediately pick up the flight of the ball and determine subtleties such as its spin and trajectory.
Naturally, different sports have different visual requirements. In some sports such as football, different team positions can have totally different visual requirements. For example, interior linemen have to detect gross body movements of opposing players as opposed to the quarterback or defensive back (the so called skill positions) who need to detect rapid movement and fine detail such as the flight of the football.
The advantages of contact lenses for sports are obvious to optometrists, but we need to educate our patients about these advantages. Some of the main advantages of contacts that can be explained to patients include:
Athletes who wear contact lenses to play sports have requirements including the following:
We are fortunate that contact lens technology has addressed most of these issues. As a result, there is a wide variety of lenses that could be prescribed for an athlete. These include:
As sports vision providers, we need to know which lens to use to help the athlete maximize his or her visual potential on the playing field.
Corneal Reshaping with Contact Lenses
Figure 32. A corneal refractive therapy lens designed to reshape the cornea and reduce the athlete's refractive error.
Another option that can be considered for athletes with refractive errors is corneal reshaping through the use of contact lenses. This procedure has many names including orthokeratology, precision corneal molding, and corneal refractive therapy (CRT).
We have had wonderful success with this procedure in our practice, not only for our general patient population, but especially for our athlete patients. Corneal refractive therapy has evolved into a science that is very predictable and extremely effective in allowing the athlete to perform without the need for any corrective lenses during game situations. Using CRT, the patient wears a contact lens that is designed to reshape the cornea so as to alter its dioptric power. The CRT lens is worn for several hours at night, and, when it is removed, the cornea holds its altered shape for the remainder of the day. This reduces or eliminates the need for glasses or contacts during this time. CRT has become very predictable and extremely fast with effects noticeable in a few days to weeks. What makes the difference is the type of lenses that we use and the technology available to design those lenses.
Advantages of CRT lens use include:
I strongly recommend considering this treatment for athletic patients.
Figure 33. Advertisement for refractive surgery performed on an athlete.
Another option for athletes with refractive errors is surgery in which the shape of the cornea is permanently altered, typically by use of a laser (LASIK). Quite a few athletes have had this done and there has been a lot of media coverage regarding the procedure.
Some refractive surgeons recommend that if an athlete is in a contact sport and wants to have LASIK surgery, protective goggles must be worn for six months after surgery. Otherwise the athlete could experience flap dislocation or trauma to the operated eye. If an athlete can’t wear goggles, then another procedure can be recommended to reshape the cornea.
Standard LASIK surgery produces a minimal decrease in contrast sensitivity probably caused by an increase in higher order ocular aberrations. However, the improvement in acuity far outweighs this drawback.
With the improvement in smoother blends and transition zones produced by LASIK, problems involving glare and haloes at night have been greatly reduced. With the advent of custom cornea or wave-front mapping prior to LASIK surgery, problems with spherical aberrations have also been greatly reduced. Wave-front mapping technology literally reflects a fingerprint pattern of an individual eye and uses this fingerprint to guide the LASIK procedure. As a result, wave-front mapping actually enhances contrast sensitivity by reducing higher-order ocular aberrations. It is theorized that because these aberrations are removed, the athlete might actually have better acuity and contrast sensitivity than would be obtained by the use of glasses or contact lenses.
(More information on wave-front technology can be found in a Pacific University College of Optometry On-Line CE course titled, "A Primer on Using Wavefront Analysis for Refractive Surgery and Other Ophthalmic Applications" by Thomas O. Salmon, O.D., Ph.D. The course catalog is available at www.opt.pacificu.edu/ce/ )
Customized sports vision training programs can be developed individually between the doctor, the patient, and the vision therapist. Much of the training we do utilizes the test instruments already described. Depending on the problems being dealt with, the training program can last about 12 weeks during which time the athlete receives one-on-one instruction and training.
Typically, we divide our training program into three stages.
Figure 34. Stages of a sports vision training program.
Stage one takes about 4 weeks and involves mostly visual calisthenics. We train tracking movements, eye teaming movements, binocular skills, and accommodative flexibility. During stage one, the athlete becomes more aware of what he or she is able to do and develops a better awareness of his or her eye performance.
A significant end result of this stage is typically an improvement in depth perception, which is obviously critical in most sports.
Stage two is called visual-motor enhancement and is dedicated to training specific sports-related visual skills including reaction time, visual concentration, dynamic visual acuity, and eye-hand coordination.
Stage three is dedicated to visualization and positive imagery. It relates to the athlete’s mental approach to his or her sport. The athlete is asked to visualize some aspect of play and create a "video" in his or her mind that will generate a positive performance. Visualization has been called mental rehearsal, and the ability to picture in the mind’s eye an object, situation, or performance can be very valuable for the athlete.
Examples of athletes performing visualization are seen in platform diving and figure skating. Television cameras often focus on a skater in a holding area beneath the arena where he or she is visually/mentally rehearsing the routine about to be performed.
Visualization is a learned skill that can be easily enhanced. The body responds to what the mind portrays. Goal-oriented visualization techniques are used to help develop consistency in athletic performance. If players can be trained to mentally perform properly, they tend to execute properly in the actual event. The mental aspect of training is definitely a part of the athletic routine and it is done at all competitive levels. A good book for learning more about this is called "The Mental Athlete" by Kay Porter and Judy Foster.
There are two ways to go about marketing a practice: internal and external marketing. An interest in sports is one thing that many people have in common, either as a spectator or as a participant. If your patient is interested, you can talk about sports during a routine exam.
In the office, you can create a "sports-oriented atmosphere" in the following ways:
It is necessary to not only promote sports vision within your practice, but also to make the entire community aware of your services. Initially you could lecture to various organizations such as:
If you are going to give a lecture, it would probably be best to do a slide or video presentation. Some are available on loan from the American Optometric Association. Also include personal slides and provide a demonstration that is fun and different. Include the audience in some of the testing (e.g., Saccadic fixator, Strobe Spex, or Tachistoscope).
How much should you charge for a sports vision screening, an examination, or training? Perhaps you will choose to donate your time to a team. This would get your foot in the door and perhaps pave the way to becoming a paid consultant later on.
Some doctors charge a minimal fee for screenings just to give their services value. Athletes and parents will pay a bit more attention to screening results when they’ve paid for them.
On the collegiate and professional level, you can manage fees in one of several ways:
For the private sports vision patient in our office, we do a complete visual examination first and then do the sports vision workup second. We provide a written and verbal evaluation. The total cost for this is about what we would normally receive for seeing primary care patients during the same amount of time.
Sports vision training can be financially rewarding, especially when a therapist is incorporated into the practice. Athletes (and their parents) are highly motivated and are willing to spend money in order to excel in their sports.
In closing, I have tried to present an overview of how a practioner can approach the examination of an athletic patient. One can have all of the equipment, needed space, and marketing expertise to set up a complete sports vision practice, but the bottom line is that you need to have a strong interest in sports to succeed in this type of practice.
You might need to learn about sports that you are not familiar with in order to communicate effectively with your athlete patients. It is important to stay current on research and technology to be able to help the athlete maximize his or her potential and hopefully gain a competitive edge. It is equally important to develop a feeling and appreciation for the motivation and discipline of the elite athlete. The critical process of establishing rapport and mutual respect cannot be realized if the practitioner does not understand the goal-oriented mentality of the athlete.
The sports vision optometrist has so much to offer the athletic patient; not just the elite athlete but also the weekend athlete who will do whatever is necessary to improve his or her game.
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Ariel, Brian. Sports Vision Training Manual. London: Brian Ariel, 1999. (contact at sports.vision@btinternert.com or www.btinternet.com/~Bra/index.html.)
Beckerman, Stephen and Zost, Michael. Management of Sports Related Eye Injuries. Chicago: Illinois College of Optometry, 1993.
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Classe, John. Optometry Clinics: Sports Vision, Volume 3, Number 1. Norwark: Appleton & Lange, 1993.
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Kaluzne, Steve and Piparo, Tony. Master the Art and Science of Putting. Winston-Salem: Sports Performance Centers of America, 1999.
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Various Sports Vision and Training Equipment
Bernell, Inc.
4016 N. Home Street
Mishawaka, IN 46545
800-348-2225
www.bernell.com
Bassin Anticipation Timer and Tachistoscope
Lafayette Instrument Co.
P.O. Box 5729
3700 Sagamore Parkway North
Lafayette, IN 47903
800-428-7545
Www.lafayetteinstrument.com
Strobe spex
Maximum Performance, Inc.
The company is no longer in business, but you can sometimes find this equipment used.
SVT Sports Vision Trainer
Sports Vision Pty. Ltd
58 Park Road
Burwood
NSW 2134
Australia
612 9747 2518 (phone)
612 9706 4212 (fax)
www.sportsvision.com.au
pelmurr@sportsvision.com.au
F.A.C.T. Contrast Sensitivity Tests, Vision Training Equipment, Stereo Acuity/Depth Perception Tests
Stereo Optical
3539 N. Kenton Avenue
Suite C
Chicago, IL 60641
1-800-344-9500
www.stereoptical.com
CSV-1000E Contrast Sensitivity Test
Vector Vision
1850 Livingston Road, Ste E
Greenville, OH 54331
800-526-7703
Info@vectorvision.com
www.vectorvision.com
Saccadic Fixator, Accommodative Rock Panel, Balance Board, Speed Trac, Peripheral Awareness Trainer, Tachistoscope, Vis-Flex Vision Trainer
Wayne Engineering
8242 N. Christiana Ave.
Skokie, IL 60076
847-674-7166
wayne@wayneengineering.com
AAA Night Sight Meter
Quantum Precision
225 Broadway, Suite 304
NY, NY 10007
Appendix 2. Suggested case history form to be completed by the patient prior to an examination. (After B. Coffey and A.W. Reichow. 1990; adapted from the Pacific Sports Vision Performance Profile)
Case History Questionnaire
This evaluation is designed specifically for athletes. The purpose is to evaluate the efficiency of those visual skills necessary for peak sports performance. Our goal is to assist you in reaching your potential. Please consider all questions carefully and answer as thoroughly and accurately as possible.
1. Have you ever had a complete visual examination by an eye care practitioner?
2. Have you ever been involved in a visual training program?
3. Do you wear glasses?
5. Do you presently wear contact lenses?
6. When did you last have your lenses checked by your eye doctor?
7. Do you ever see blur?
8. Do you ever see double?
9. Do you ever feel you have difficulty “keeping your eye” on a moving object?
10. Do you notice variations in your performance during a game or event?
11. Do you notice variations in your performance over a period of time such as in a tournament?
12. Is performance consistent during critical competition situations?
13. Is your performance the same for night competition as for day competition?
14. Do you experience loss of concentration during sports performance?
15. Cite examples related to questions 8-13
16. Are you experiencing any visual difficulties?
17. Please rate your feeling regarding the importance of vision in your sport (1=not important, 9=extremely important)
18. Do you feel vision is important to your particular sport?
19. Do you use visualization/imagery techniques?
20. Have you ever suffered head injury or have you ever had injury, surgery, infection, or disease involving your eyes?
21. List any other visual performance concerns that you may have.
Contact this author:
Alan M. Berman, O.D.Pacific University College of Optometry provides On-Line CE as a service to optometrists. The college does not endorse or recommend any products, equipment, or services that might be discussed in the courses. Courses are prepared by individuals believed to be experts in their areas of specialization who are compensated for their efforts. The College relies on their expertise to produce accurate and timely courses. Questions or concerns about courses should be directed to the individual authors and/or the Continuing Education Department at the College of Optometry at kundart@pacificu.edu.
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