Cataracts are the leading cause of blindness in Cambodia. Curable by a simple surgery that is unaffordable to most in the Kingdom, Cambodia Vision volunteers spent a week in Kampong Speu performing the operation for free.

Hours earlier, Hang Pheng, a 77-year-old farmer from Phnom Penh’s Por Sen Chey district, had been blind. He and his wife were two among hundreds of patients who went under the knife this week at Kampong Speu Referral Hospital to have their cataracts removed by an Australian surgical team.

“The outside of my eyes looked OK, but on the inside, I could not see,” he said, chuckling as he sat in the recovery room on Tuesday morning wearing thick black sunglasses to protect his sensitive, post-surgery eyes.

With his sight restored, Pheng hopes to be able to take better care of himself in his old age, adding that his loss of sight had caused him to neglect his health in general.

The restoration work was done by Cambodia Vision, an Australian NGO founded in 2006 to tackle blindness and other visual problems in rural Cambodia. For the past six years, it has annually sent medical teams to the countryside for one week to perform cataract surgeries. Past clinics have taken place in Kampong Speu, Kampot and Kampong Thom. This year, 48 Australian volunteers and 10 Cambodians came to help.

In 2012, Cambodia Vision assessed 2,800 patients from 18 provinces and provided 371 cataract operations. The team hoped to provide 400 operations this year. Surgical patients also received two free meals at the hospital, $5 for travel expenses and post-operation treatment.

“The idea is that in the end, if the outcome is good, these people can see and go back to become functioning humans,” said William Robinson, an optical technician whose job it was to take the measurements of the eye ahead of an operation.

Although preventable and easily treatable with relatively minor surgery, cataracts are the single most common cause of blindness worldwide. The problem is particularly acute in Cambodia, where cataracts caused 75 per cent of blindness in people more than 50 years old, according to a 2012 AusAID report. High exposure to sunlight without sunglasses is largely to blame, said Cambodia Vision communications officer Thida Yang. The condition primarily affects the elderly, but infants have also been through the centre.

In a country with a shortage of optometrists, cataracts tend to accumulate for years before they are discovered. Ophthalmologist Chris Brown said that the cataracts in Cambodia are far denser than those he deals with in Australia.

“These people have been going years and years, and a lot of them are blinded by cataracts,” Brown said, adding that cataracts are usually discovered quickly in developed countries. As a result, Brown said that he typically spends at least 45 minutes on a procedure that would take just 20 minutes at his practice in Sydney. All the equipment is shipped from Australia and is up to par with modern standards.

Before surgery, patients were given routine ocular examinations. Yang said that most visitors did not have cataracts, with many visiting only to have their eyes checked. If a cataract was not discovered, the patient may have been prescribed antibiotics to treat infections or eyeglasses for imperfect sight.

“They will often say something like, ‘I look at the sun and my eyes hurt,’ so we give them sunglasses and educate them about UV protection,” head optometrist Susan Ang said. This year, the team brought 1,500 pairs of eyeglasses and 4,000 pairs of sunglasses to distribute among Cambodians.

Tin Sophan, a 28-year-old farmer from Kampong Speu visiting the clinic, said he had no cataract symptoms but nonetheless wanted an eye checkup.

“I don’t need an operation, but I do have eye pain,” Sophan said, adding that his entire family came for examinations that day. He was far from alone that morning, with 900 visitors in the queue before midday.

In some cases, cataracts were discovered in patients who came with other complaints. Sim Lon, a 66-year-old patient from Kampong Cham, visited the clinic in hopes of getting help for chronic twitching in her left eye that resulted from a venomous snake bite in 1979. Although the doctors were unable to stop the twitching, a cataract was discovered and removed.

Despite the team’s capabilities, Yang said not all patients could be helped. In cases where patients suffer from retinal damage, pterygiums (“surfer’s eye”) which can be caused by long-term sun-exposure from working outside, and other serious eye problems, the doctors could only prescribe simple treatments for the symptoms and provide education. With the team only in town for a week, the surgeons were limited to around 400 operations. In some cases, patients with untreated pre-existing conditions, such as high blood pressure or diabetes, were at too high risk for cataract removal. If possible, the doctors prescribed medication to temporarily stabilise patients’ conditions to make them safe for surgery. Others were turned away because their cataracts were deemed inoperable. But for the lucky ones, the surgery seemed nothing short of a miracle.

“I cannot describe how happy I feel,” an emotional May Sophat, a 75-year-old patient from Kandal, said in the recovery room.

“If it wasn’t for that team, I wouldn’t be able to see.”