BEIJING, -- Every now and then, Liu Hua, 54, thinks of her little friend Nshimirimana Thierry in Burundi, east Africa, a once cataract-blinded boy who gained vision thanks to Liu's surgery last year.

"I'll never forget his pure smile when the bandages came off," said Liu, an eye doctor from northeast China's Liaoning Province. "He had been blind for more than three months before the surgery."

Liu is among thousands of medical aid personnel dispatched to 41 African countries in 2016. Their endeavors received a warm response at a conference -- "China-Africa Health Cooperation, From Commitments to Actions" -- in Pretoria, South Africa earlier this week.

Representatives from 31 African countries spoke highly of China's support for African countries. China had also signed an agreement on a free-cataract-surgery program with African countries, including Sierra Leone.

But it was not the first time for eye surgery programs. Since the China-Africa Brightness Action initiative was launched in 2010, eye doctors from China have traveled to Africa frequently to treat cataracts.

According to Liu, most patients who suffer from cataracts in Africa cannot receive proper treatment due to high surgery costs and a lack of medical professionals and facilities.

Liu went to Yemen in 2011 with the medical team of China-Africa Brightness Action, and was deeply touched by the poor condition people suffered. Inspired, later she decided to visit Africa without hesitation.

Liu, together with other four top eye-doctors from northwest China's Qinghai Province, spent over 20 hours flying to Burundi last December, and performed nearly 200 cataract surgeries within a week.

"I conducted 29 surgeries on my peak day," Liu said. "Fifteen year-old Thierry was my youngest patient, and he told me that his wish was to be able to play football."

She still remembers when she first met Thierry in Prince Regent Charles Hospital in Bujumbura, capital of Burundi, and his grandmother begged for help, saying that the boy was her only relative as his parents and grandfather died years ago.

"The old lady told me that Thierry had to drop out of school because of the blindness, and she could not imagine what would happen to his life as a poor blind boy," Liu said.

Liu was so relieved when Thierry showed his joy after the surgery. "Even his neighbors were moved to tears," he said.

Though the country's largest public hospital, Prince Regent Charles Hospital has no eye doctor, not to mention a lack of medical facilities and frequent power outages. Moreover, language barriers and the complicated conditions of patients bring difficulties. These are common difficulties for Chinese medical personnel in Africa.

Zhao Junmei, a seasoned eye-doctor with more than 20 years of experience working at Shanxi Eye Hospital in northeast China, performed nearly 300 eye surgeries within a month in Cameroon last year.

"The poor conditions were beyond my expectation; they do not even have an operating room," Zhao said. "I told myself that no failure was allowed, this was the only chance for these African people to see the light."

Cataract surgery requires implanting artificial lenses into a patient's eyes to restore light, and Eyebright Medical Technology, a Chinese company, provided the artificial lenses for a medical team in Cameroon.

"I am proud that a Chinese company can master the core technology, so that we do not have to rely on expensive foreign products," Zhao said.

She went to the hospital on a two-hour bus drive every day, and there were many patients already waiting when she arrived.

"There were even patients who had traveled to Cameroon from other countries for eye surgery," Zhao said. "I had my lunch next to the operating table almost every day."

The most unforgettable day during her African mission was that when she helped 11 cataract patients with HIV or AIDS.

"Every patient, including those who suffer from HIV or AIDS, has the right to be treated." Zhao said. "I cannot understand their language, but the smiles are universal. I never get tired of seeing their cheerful smiles."