RULE BREAKER: Hiro-Pon, of Japanese double act Gamarjobat, can do the impossible with his eyes.

A Japanese busker is performing a trick so dazzling it defies science.

Hiro-Pon, of Japanese double act Gamarjobat, who is performing in Christchurch this week as part of the World Buskers Festival, has a trick where he can move each eye independently like a chameleon.

The trick caught the eye of leading Kiwi brain researcher Michael MacAskill when he saw the act in Christchurch a couple of years ago. He believed it was neurologically impossible, so he took the performer into a laboratory to record and analyse the eye movements.

His findings helped disprove a 19th-century scientific theory, known as Hering's law, that states both eyes move in unison and that this is hardwired into the brain.

"This was a bizarre case where someone was able to do something that we previously thought was impossible," MacAskill said.

"He is breaking that law in a very subtle way and shows there is a way to break that circuitry. It is an important discovery in a very arcane field.

"In essence, our eyes can be a bit more independent and chameleon-like than we thought."

His findings were published in a leading medical journal, Neurology.

Hiro-Pon was surprised at the scientific significance of his trick.

"That is a surprise. Wow. But it is so easy for me . . . I don't know why the scientist was so interested because everybody can do this, I think."