Among the treasured souvenirs that eye specialist Hou Xianru keeps from his extensive medical missions to restore eyesight is an embroidered handmade cushion gifted by an octogenarian Uzbek patient.

"She regained clear vision after I performed cataract surgery. Noticing that we spent long hours examining and operating under the microscope, she stitched the traditional item and insisted we take it home with us," said Hou, a senior ophthalmologist at Peking University People's Hospital.

"She hoped that her small gift would help ease our fatigue at work. Though modest in size, it carries the sincere gratitude of someone from afar. I've cherished it ever since," he added.

Such heartwarming moments define Hou's journey over the past seven years as a medical aid worker with Lifeline Express, a project that transforms trains into mobile hospitals for cataract operations.

The project was launched in 1997 as a gift to the Chinese mainland from the people of Hong Kong to commemorate the city's return to the motherland. It has since provided free surgery for 240,000 patients in 28 provincial-level regions across China.

Since 2016, the project has been assisting neighboring countries under the guidance of the National Health Commission, carrying out more than 4,300 eye operations overseas, including some in Kyrgyzstan, Tajikistan and Uzbekistan.

Hou first participated in Lifeline Express' domestic assignments in 2004, crisscrossing remote regions with scarce healthcare.

"The work on the train-turned-hospital is free of distractions. Away from the hustle and bustle of urban life, my mind is able to sharply focus on helping more patients regain clear vision," he said, adding that he has been able to hone his surgical skills in the process.

As Hou studied and trained in Russia for over a decade, it gave him an edge in terms of communication when he joined medical missions in Central Asian countries in 2018.

"During international missions, we face multiple challenges such as communicating effectively with local officials and medical staff, optimizing use of limited medical resources, and mobilizing local teams to complete workloads on tight schedules with us," he said.

Reflecting on his work across five cities in Uzbekistan and Kyrgyzstan, Hou emphasized that trust and friendship develop incrementally through shared efforts.

"Sometimes, just when we wrap up work in one city and are about to leave, local doctors ask us to stay longer as hundreds of more patients have registered and are waiting," he said. "As a result, we often return to the same city multiple times."

Chinese medical professionals also help train local doctors and nurses and keep in touch with them through online messaging platforms, he added.

Guo Lei, head of the Lifeline Express office at the National Health Commission's International Health Exchange and Cooperation Center, said that 989 free cataract operations were successfully performed in Tajikistan, Kyrgyzstan and Uzbekistan last year, bringing the total number carried out in Shanghai Cooperation Organization member states to 2,187.

Lifeline Express has set up four blindness prevention centers in Uzbekistan, Kyrgyzstan, Tajikistan and Nepal.

At the center in Tajikistan's capital Dushanbe, which started functioning in late May, the project donated 2 million yuan ($278,500) worth of ophthalmic equipment, medicines and other medical supplies, Guo said.

Doctors from Peking Union Medical College Hospital also pioneered an advanced technique at the center called vitrectomy, which treats problems in the retina and vitreous, she said.

Yu Weihong, chief of ophthalmology at the Peking Union hospital, has participated in Lifeline Express' overseas programs since 2016, including the recent mission to Tajikistan from May 26 to June 2.

"Our sustained efforts have helped many cataract patients regain clear vision, and we have trained local doctors in basic surgical techniques," Yu said.