And with only one shot at gold, Great Britain's women's hockey team are determined to keep their eye on the ball and leave nothing to chance. Overcoming the glare of the Beijing sun is vital if they are to triumph and they are pinning their hopes on tinted contact lenses to give them an edge. Determined to hold any advantage they can, the team knows that at this level, the battle is as much about technological innovation as human endeavour. Just over a third of the side will take to the pitch wearing orange-red lenses during their first match against Germany. And although they may look intimidating, their purpose is not purely psychological. "They make them look like the devil," head coach Danny Kerry joked. "They are high contrast but they also allow you to track the ball and one of the theories is that if you're squinting all the time, it fatigues your muscles. "The girls who have persevered with them swear by them." With the difference between success and failure often coming down to tiny details, Team GB has been meticulous in its preparation. And the lenses are just another example of the reliance on science in the quest to add to a solitary bronze medal in the women's competition, secured 16 years ago in Barcelona. "They're like sunglasses but as a contact lens, so it prevents glare," said skipper Kate Walsh. "Both the goalkeepers like to wear them and a couple of the girls do on a really bright day, so you're not squinting a lot, which can cause headaches." For Olympic athletes, the difference between first and second place is everything. Former Olympic champion Allan Wells, who won the 100m gold medal at the Moscow games in 1980, said: "It's a clever, intuitive way to go. I was using every psychological and physical means within the rules. "You maximise it in every way ... anything that gives you the edge." Wells wore a favourite hat when he entered a stadium, which boosted his confidence and singled him out from the opposition. "I always wore a red, white and blue hat, which made me feel different. I was the only one in the stadium with that hat and that helped me," he said. "It sounds silly but that gave me the edge. It's about knowing what is good for you." Frank Munro, former chairman of Optometry Scotland, said the lenses had been used by golfers and other athletes to improve performance but it was down to the individual. He said: "I don't think the science supporting it is terribly strong. There may be a psychological element."