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Protocol
Due to time and space constraints it was not possible to carry out full sight testing on each athlete. Instead, they all underwent autorefraction and anyone showing significant ametropia was referred to their local optometrist. This is not an ideal scenario. It is always preferable to perform full checks on refraction, orthoptics and ocular health prior to sports vision assessment.
Following autorefraction, each athlete underwent a battery of sports based vision tests using the Acuvision VTA (Visual Test Administrator) (Figure 1) and Acuvision 1000 visual skills trainer (Figure 2).
The Acuvision VTA (Visual Test Administrator) was used to measure dynamic acuity and reaction timing. This incorporates specially designed hand buttons and foot pedals, used in conjunction with a computer-based program and a laptop computer.
The Acuvision 1000 is a 0.8x1.3 metre wall-mounted device divided into a matrix of 39x25 squares. These squares each contain a light that can be illuminated either randomly or as part of a pattern. The lights are then extinguished by pressing the board at the position of the light. The matrix of squares contains 120 hidden red target lights, a green 'fixator' light, a key pad, and a numeric display.
The Acuvision 1000 visual skills trainer has many functions. The device can be set to several modes to allow measurement of different aspects of visual function. These include the following:
- Proaction/reaction: the red target lights are illuminated one at a time, in a random order. The athlete has to extinguish the light as fast as possible. Measurements are taken of the athlete's reaction and response times.
- Visual concentration: as for the proaction/reaction setting, except for the additional use of a central green fixation light. The fixation light comes on and off randomly during the program. The athlete should only extinguish the red target lights when the green fixation light is on. If the athlete extinguishes a red target light when the green fixation light is not on, a point is deducted from their score.
- Peripheral awareness: as for the proaction/reaction setting, except the central green fixation light is permanently on. The athlete must maintain central fixation and use peripheral vision only to extinguish the red target lights. Settings can be adjusted to target a particular area of the visual field.
- Reaction timing: measurements are taken over a fixed time span (30 seconds) and as many target lights as possible are extinguished. This allows calculation of reaction time and speed per target.
Rugby union
Rugby union is a game played between two teams of 15 players. Each team consists of eight forwards and seven backs.
The collective role of the forwards is to gain possession of the ball and get it to the backs, who try to develop a running play. The forwards are regarded as the heavyweights of the team. The backs should be more mobile, typically with the pace to translate the possession provided by the forwards into tries. As fitness and skill levels have improved (particularly in the professional era) the roles performed by the backs and forwards are not only interdependent but also frequently interchangeable.
The team that scores the greater number of points is the winner. There are four ways of scoring points:
- Try - 5 points
- Conversion - 2 points
- Penalty - 3 points
- Drop goal - 3 points.
A try is scored by grounding the ball in the opposition goal area. The player must be holding it in his hand(s) or arm(s) when he brings it into contact with the ground. The ball can also be deemed to be grounded if a player falls on the ball, but the front of the body, from the waist to the neck must make contact with the ball. Every try is further rewarded with a kick at goal, and can increase the score by another two points. This is called a conversion. The kick is taken from a point level with where the try occurred. Penalty kicks are awarded when an infringement takes place and a drop goal is scored when a player, during normal play, kicks from the hands, striking the ball as it hits the ground and sending it between the goal posts.
Results
Measurements were taken from all squad members. This consisted of 33 players, divided into 17 forwards and 16 backs. One obvious area of comparison during the sports vision assessments was to compare the performances of the different player types to see if there was a significant variation or not. Comparisons were also made of performance versus age.
As can be seen from the sample graph (Figure 3), very little statistical difference was noted between the performance on the Acuvision 1000 of the forwards and the backs. This was the case for all categories except for that of reaction timing. In this category, the backs showed reaction times consistently equal or quicker than the forward players.
Next comparisons were made between player performance and age. In each category, a reduction in player performance was noted with increasing age. This was the case for all categories except reaction time, where the older players performed better.
It should be noted that when dealing with reaction times, a lower score is faster and therefore better than a higher score. This is the opposite of all other categories, where a lower score is worse than a higher score.
Discussion
Protocol
As mentioned at the beginning of this article, it would have been preferable to carry out full refraction and ocular health analysis prior to the sports vision assessments. Unfortunately, time and space restrictions prevented this. Perhaps this could be rectified in future by visiting the squad on more than one occasion or utilising more than two optometrists to take measurements.
Equipment such as the Acuvision 1000 and SVT allow athletes to train their hand/eye coordination. Following initial assessment, such as this, it would be beneficial to revisit the athletes at regular intervals to try to improve their performance. This is one of the main goals of the sports vision optometrist.
Equipment
In many of the categories measured, the results are very similar for all of the athletes. It is noted that the sample group only contains elite athletes (rather than a spread of the general population) and that these athletes are all in peak condition (preparing for the World Cup). This will have an effect on the range of performance.
Perhaps when dealing with such closely matched groups, it would be beneficial to be able to test to a smaller degree of accuracy. Some more recent equipment for assessing hand/eye coordination (SVT) allows for measurement down to 0.001 second,1 rather than the 0.01 second with the Acuvision 1000.
Conclusions
- In this test sample (n=33) of elite rugby players, Reaction time was noted to be quicker among backs than forwards.
- There was no difference noted between the performance of backs and forwards in tests of hand/eye coordination and peripheral awareness.
- Visual function such as hand/eye coordination and peripheral awareness was shown to decrease with age, with the exception of reaction time, which was maintained (or even improved) with age.
- Visual training is the next logical step following initial assessment such as described in this article. This has been shown to give an improvement in measurements such as hand/eye coordination.2
References
- Training eye hand coordination on the SVT - Pierre Elmurr BAppSC (Orthoptics) DOBA MAppSC (ExerSportSc) - , School of Applied Vision Sciences, Sydney, Australia - www.sportsvision.com.au/svtstudy.pdf
- Can Eye Hand Coordination be trained on the Acuvision 1000? - Michael Kunicki, School of Applied Vision Sciences, Sydney, Australia - www.sportsvision.com.au/admin/pdf/Acuvision%201000%20study.pdf
? Colin Moulson is a sportsvision optometrist running a purpose designed sportsvision clinic in Glasgow, Scotland