By Julie Clothier for CNN
(CNN) -- When you are at the top of your game in sport, it is difficult to make big improvements to your form.
But a scientist at the University of Calgary, Canada, is getting impressive results from testing and training players' vision, using eye-tracking and motion analysis technology to do so.
Professor Joan Vickers, a specialist in kinesiology --- the study of anatomy and body movement -- has been researching the role of gaze and attention in sport for more than 20 years.
She has been developing the "Quiet Eye" technique since the early 1980s, in an effort to understand how vision can control and guide the body's movements.
The technique is a measure of visual focus, recorded with a variety of technologies, which, according to Vickers, gives an athlete insight into their actions.
Vickers told CNN that the technique is beginning to "emerge as a potential predictor of elite athlete performance."
The "Quiet Eye" is based on key elements of data, which Vickers compiles during her research -- what the athlete sees and when, and for how long.
The first is the optimal location of the eyes' focus in space. For example, the best place on which to focus in golf is the back of the ball, while in basketball it is the front of the hoop.
"The precision of the quiet eye location often mirrors the precision required to perform well in a sport. In golf, precision of movement and precision of focus are paramount," says Vickers.
The second is the when the eyes begin to focus. The timing of focus is crucial, says Vickers, and varies depending on the sport.
The third is when the players' gaze leaves the "optimal location."
"In golf putting, for example, it has to stay on the back of the ball through the stroke and dwell for 200 or 300m on the green, after contact. Most golfers do not do this consistently," says Vickers.
The final quality is the duration of the quiet eye's period.
"It's about their ability to maintain a single focus even as all the motor activity is going on," she says.
"The top athletes that I work with have wonderful physical attributes but what some of them lack is visual focus and concentration," she says.
"Because this type of data has not existed in sport science before, it is new information that many find incredibly helpful -- most athletes don't have a motor problem. They have a concentration problem or a focus problem."
This, she says, can be fixed by first testing these things to see where improvement is needed, and then, once the weaknesses have been identified, train the players' attention system to perform better by controlling the gaze.
Technology has made Vickers' research easier, she says. Twenty years ago the technology to track eye movement did not allow the athlete to move.
Now lightweight eye trackers are small enough to be worn without affecting a player's performance.
Essentially an eye tracker monitors the movement of the eye and head -- in other words, the gaze -- as a unit.
It is able to locate the eye and see where the wearer is looking by monitoring the movement of the pupil.
The tracker records information using two miniature cameras and a mirror, which are hooked up to a computer.
As well as the eye tracker, Vickers uses external cameras to record what the body is doing. Eight or more cameras can be used at any one time to monitor the player.
Data based on the players' eye, gaze and motor movements are captured every 33.33 milliseconds per frame -- a time code generator synchronizes the eye image, the gaze image and the body image.
Vickers has used her technique to carry out quiet eye testing and training athletes in a wide range of sports, including golf, basketball, ice hockey, volleyball and rifle shooting, with impressive results.
When the university of Calgary's women's basketball team started using quiet eye training, the team's free throws scoring statistic improved in competition by 22 percent in two seasons and the team went from being ranked 17th in their league to second in Canada.
A university in the Netherlands is now also using the technique and finding the same kind of increases.
"Normally when you train athletes at the highest level you get a one or two percent improvement," says Vickers.
"What I like about it is that's it's all natural. It's about training your mind and your body at the same time in the settings that count. It has the potential of being extremely powerful."