The 55-year-old, from a remote village in the Sonid Right Banner district, 200km from the city of Xilinhot in Inner Mongolia, is one of 4.5 million people on the mainland to have been blinded by cataracts.

Two years ago, her family managed to raise 3,500 yuan - a year's income for the household - to bring a doctor from Beijing to Xilinhot to operate on her right eye. It was all they could afford.

Last week, she was finally able to have surgery on her left eye at the Xilinhot People's Hospital at a cost of just 700 yuan, thanks to a programme launched by the Project Vision Charitable Foundation.

'I am so happy and grateful. Now I can go home and sew again,' she said, smiling as brightly as a red plum flower - as her Mongolian name translates - when the bandage covering her right eye was removed on Friday, two days after the operation.

Her daughter, Xin Tuoya, said blind neighbours had no idea what had gone wrong with their eyes, and most rural doctors did not have the skills to treat them, so they just accepted the loss of sight as their fate.

'My mother was lucky enough to have her case picked up by a county hospital doctor two years ago, but many other blind people are still suffering,' Xin Tuoya said.

The foundation raised HK$20 million to begin the project. It hopes to raise 100 million yuan, and within five years, open 100 eye clinics able to perform a total of 100,000 cataract operations a year.

Three more will be opened this year, in Guizhou , Shaanxi and Chongqing .

Dennis Lam Shun-chiu, chairman of Project Vision, said the programme aimed to train local doctors in cataract surgery and provide affordable services to patients.

Cataracts - a condition in which the eye's lens gradually becomes opaque - is a leading cause of blindness worldwide.

The mainland lags many countries in the resources it puts into cataract operations. While the United States conducts 10,000 cataract operations per million people, and India 3,900 per million, the mainland can manage only 445 per million.

Project Vision has borrowed a successful model that Dr Lam's team developed in Chaozhou , Jieyang and Shantou (collectively known as Chaoshan) in 2004 for a separate charitable project, Caring is Hip, under which eye doctors from the Chinese University of Hong Kong and Shantou University train rural doctors to conduct cataract operations.

The six eye clinics set up in Chaoshan, Guangdong, have treated more than 5,000 patients, and five doctors have been trained to conduct cataract operations independently.

Dr Lam, chairman of the department of ophthalmology and visual sciences at Chinese University, said treating cataracts was the first step towards eradicating blindness.

'Cataracts are causing about half the blindness cases on the mainland and are highly treatable. By training local doctors to treat local people, we are transferring skills and helping them assist their own communities,' he said.

The standard cataract treatment can be costly, but Dr Lam has helped develop a technique that does not require sutures and takes only 15 minutes.

'It costs 5,000 to 10,000 yuan for a cataract operation in major cities on the mainland. We only charge 700 yuan in the rural areas, and with good cost control we manage to make a small profit to invest in doctors' training,' he said.

The charity plans eventually to develop the centres into integrated eye clinics able to handle more complicated conditions.

Ma Ning, a doctor at the hospital in Xilinhot, looked excited as he showed off the operating theatre where he uses skills learned from Hong Kong doctors to help patients from his home city.

'It is a good learning process. We know better surgical skills and we can help more patients,' he said.

For more information about Project Vision, call 2762 3125.