Why is Steve Smith wearing black tape under his eyes?

Australia batter Steve Smith is wearing black strips of tape under his eyes while batting in the second Ashes Test against England in Brisbane.

Smith was photographed wearing the patches while batting in the nets, but he discovered he was initially wearing the patches, known as 'eye black', incorrectly during the practice sessions.

Players are using a pink ball in the day-night Test which is played under floodlights.

The patches have been used in the past by former West Indies batter Shivnarine Chanderpaul to reduce the glare caused by the sun and improve contrast.

Eye black is commonly used in American sports, including American football, baseball and lacrosse.

Babe Ruth, one of baseball's greatest players, used it in the 1930s and seven-time Super Bowl winner Tom Brady famously wore paint under his eyes too.

"I actually messaged Shivnarine Chanderpaul and asked him what his thoughts were, whether he wore the chalk or the strips," said Smith.

"He said the strips, and he thinks it blocks out 65% of the glare. And he also said, 'I've seen photos and you're wearing them the wrong way'.

"So yesterday I put them on the right way," he added.

A number of tests have been conducted this century to determine whether eye black actually has an effect.

A 2008 episode of American science-entertainment television show MythBusters ran tests and found that they made no real difference compared to light coloured make-up.

Results changed after the subject put on a baseball cap, finding a noticeable reduction in the amount of light exposure. However, glare was not fully eliminated.

A separate study by Yale University found that the paint helped to reduce glare and improved contrast sensitivity, but that test was subject to unavoidable learning bias.

A second study by the University of New Hampshire reached an insignificant result due to testing a small sample size. But it did find that they only made an impact from short distances.

Whether the patches worked as a placebo or not, Australia's stand-in captain notched a half-century from 67 balls at the Gabba to help his side close in on England's first innings total.

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