Russian maths genius Grigori Perelman, who famously turned down a $1 million prize last year, now appears to be refusing free eye surgery for his mother.

Mayoral officials in St Petersburg, where the 44-year-old eccentric shares a home with his mother, said Perelman had yet to respond to the city's offer of eye care.

"We recently learned from neighbours of the Perelman family that his mother had ophthalmological problems and needed treatment," said the administration of Frounzenski district, where the mathematician lives.

"At the end of May we sent an offer of a free operation if necessary. But we have yet to receive a response from him."

In March last year Perelman was announced as the winner of the $1 million Clay Millennium Prize after proving the Poincaré conjecture, a topology problem proposed by French mathematician Henri Poincaré in 1904.

He later announced that he would not accept the prize because of a "disagreement" in the maths community.

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