Abstract
Purpose: :
To determine the effect of magnitude and type of retinal defocus on golf putting accuracy, as well as related eye, head, and putter movements.
Methods: :
Eye, head, and putter movements were assessed objectively and dynamically along with putting accuracy in sixteen young-adult, visually-normal inexperienced golfers, during a fixed 9 foot golf putt. The eight test parameters included eye position, eye movement root mean square (RMS), head position, head movement RMS, putt position, putt duration, putt amplitude, and putting accuracy for a small (3cm) and large (12cm) target. Convex spherical (+0.50D, +1.00D, +1.50D, +2.00D, +10.00D) and astigmatic (+1.00Dx90, +2.00Dx90) lenses were added binocularly in a counterbalanced manner to create various magnitudes and types of retinal defocus. All measurements were obtained with a custom-designed, computer-based, head-mounted eye and head movement sensor system, along with a putter-mounted position sensor. The eye position sensor system consisted of an infrared reflection limbal tracking system, while the head position sensor used a head-mounted potentiometer. The putter sensor system consisted of an accelerometer with an array of phototransistors aligned in the direction of the putting stroke. Resolution and linear range for the eye, head, and putter sensor systems were 15 min arc and +/- 25 degrees, 0.5cm and +/- 25cm, and 0.25cm and +/- 45cm, respectively. Sampling rate was 100Hz. Sensor signals were input into a conventional laptop computer and analyzed via customized software.
Results: :
Putting accuracy was significantly reduced only under the highest spherical blur (+10.00D) lens condition. No significant differences were found between any other lens conditions for eye, head, or putter movements. There was an inverse trend between the degree of myopia and putting accuracy.
Conclusions: :
Small amounts of spherical and astigmatic retinal defocus had a minimal impact on overall golf putting performance, except for putting accuracy under the highest blur condition. This is consistent with the findings of related studies. For a fixed putting distance, factors other than quality of the retinal image, such as blur adaptation and motor learning, appeared to be sufficient to maintain a high level of motor performance.
Keywords: eye movements • adaptation: blur • refraction