July 5, 2017
Amsterdam, NL – Stereo vision allows individuals to perceive depth differences in their
surroundings. Important to pedestrians and drivers, for example, depth perception plays a key role in many
sporting activities. If the ability to accurately determine the distance and speed of a fast-moving object can
be improved, athletes have the potential to improve their performance. In a new study published in
Restorative Neurology and Neuroscience, researchers found that by training athletes using repetitive
stereoscopic stimuli, their reaction speed to those stimuli could be significantly improved.
Using a commercial vision training apparatus (c-Digital Vision Trainer®), 15 male soccer athletes were
trained over 12 sessions of 15 minutes each over a period of six weeks. They were presented images on a
3D-TV simulating moving soccer balls. Each ball appeared to be both moving towards them and rotating,
with one ball appearing to be closer to the observer.
Subjects were required to pick out which ball is “in front” and indicate this as quickly as possible by
pointing to that ball. The time to see the depth difference plus the time for the motor reaction was defined
as “response time.” The total “response time” minus the time for the motor reaction was defined as
“processing time” in the tests. By testing different grades of complexity of the stimuli, the time for the motor
reaction and the “processing time” could be differentiated.
Caption: Illustration in 3D of the dynamic stereoscopic stimulus: the target objects are constantly moving towards the observer.
“Elite athletes often operate at suprathreshold levels, which cannot be determined by classical stereo
vision tests,” explained principal investigator Georg Michelson, MD, Department of Ophthalmology of
Friedrich-Alexander- University Erlangen-Nürnberg (FAU), Erlangen, Germany. “Processing time, as the
reaction time in which the absence or presence of depth was identified correctly, is of better predictive
value for perceiving depth than the stereo threshold only. Our aim was to determine whether repetitive
dynamic stereo testing with a limited time frame can induce a significant long-lasting improvement of
stereo processing time in a group of young athletes with highly developed stereo acuity.”
The apparent distance between the nearest ball and the three other balls can be adjusted in the
apparatus. At large distances, each subject would likely be able to identify the nearest ball quickly, but at
small distances, only those with excellent dynamic stereo vision would react quickly.
By testing athletes with highly developed stereo acuity, researchers determined that repetitive training
decreased their processing time, and that this ability was persistent for six months after the training ended.
After six training sessions, the athletes’ processing time at 11 arc seconds (11/3600 degrees of an arc)
decreased significantly from 804.4 milliseconds to 403.7 milliseconds. When most of the subjects were
tested again after six months, their processing times were the same as in their last training session.
Caption: Mean stereo processing time at 11 arc secs disparity difference of all 15 subjects by number of trials and six months after the last training as measured with the c-DIGITAL VISION TRAINER® test.
While this study has implications for athletic performance, non-athletes with impaired stereo vision can
also benefit. Amblyopia, or “lazy-eye” syndrome, can result in weak or missing depth perception, and
therapies that might improve this condition would be welcome.
According to Dr. Michelson, “Research of the past few years is increasingly changing the focus from pure
monocular treatment to combination therapy with the fixing eye kept open and, finally, binocular therapy
based on perceptual training. As recent studies additionally show repetitive identification was already able
to improve visual acuity, we think that now it is the right time to investigate the same for stereo processing
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NOTES FOR EDITORS
Schoemann, Matthias Lochmann, Jan Paulus, and Georg Michelson, MD. Published online in advance of
Restorative Neurology and Neuroscience, Volume 35, Issue 4 (August 2017), DOI 10.3233/RNN-170729,
by IOS Press.
Full text of the article is available to credentialed journalists upon request. Contact Diana Murray, IOS
ABOUT RESTORATIVE NEUROLOGY AND NEUROSCIENCE
An interdisciplinary journal under the editorial leadership of Bernhard Sabel, PhD, Restorative Neurology
and Neuroscience publishes papers relating the plasticity and response of the nervous system to
accidental or experimental injuries and their interventions, transplantation, neurodegenerative disorders
and experimental strategies to improve regeneration or functional recovery and rehabilitation. Experimental
and clinical research papers adopting fresh conceptual approaches are encouraged. The overriding criteria
for publication are novelty, significant experimental or clinical relevance and interest to a multidisciplinary
RNN Editorial Office
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Institut für Medizinische Psychologie
Otto-v.- Guericke Universität Magdeburg
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