(CNN) - The pain is so intense that people don't dare blink. To do so could mean scraping away what little sight they have left.
Instead, they resort to tying scarves around their heads in hopes of keeping their eyes from closing. Others carry tweezers and pluck out eyelashes and bring relief from the constant pain and impairment; these hairs, inverted by their disease and rubbing against their eye, are to blame.
But the real culprit is a bacterium, Chlamydia trachomatis. Repeated or prolonged infection with it scars a person's eyelids until they turn inward, causing lashes to rub against the eye constantly.
"The pain is excruciating," said Simon Bush, director of the neglected tropical diseases program at international nongovernmental organization Sightsavers. "People tell me it's like sandpaper scratching over your eye every time you blink."
Eventually, the cornea is scarred, slowly decreasing vision until blindness sets in.
"Once you get to a particular stage, it's irreversible," Bush said.
This is life with trachoma, a preventable infection that has impaired the vision of almost 2 million people worldwide today, with a further 200 million at risk across 41 countries.
But in recent years, countries once struggling with the disease have proved that they can beat it.
Oman came first in 2012 with the announcement that it had eliminated the disease as a public health concern. Morocco followed suit in 2016 and then Mexico, Cambodia and Laos in 2017.
Last month saw Nepal achieve the goal, and Ghana declared this month that it had eliminated the disease -- the first country to do so in sub-Saharan Africa.
"Ghana has eliminated a painful eye disease which has devastated the lives of millions of its most vulnerable people for years," Bush said. "But the fight does not end here. Many other countries are on the cusp of elimination and must continue to push for the elimination of trachoma -- and other neglected tropical diseases -- across the world."
There are five levels of trachoma severity, from mild inflammation of follicles to at least one ingrown eyelash and eventually corneal opacity, in which a cornea appears cloudy or white from scarring, impairing the person's vision.
It starts with a single infection.
"The disease thrives in areas that are traditionally short of water," Bush said of the "trachoma belt," which spans from Northern Nigeria to South Sudan.
In these regions, water is a precious resource, he adds, meaning people might not be able to spare enough to wash their or their child's face, aiding the spread of infection.
Trachoma spreads through contact with liquid from the eyes or nose of an infected person or contact with contaminated materials, such as clothing or towels. Flies can also spread infections through contact with people's faces.
Washing your hands and washing your face regularly can help curb the spread, but when it's a choice between washing with water or drinking it, the latter comes first.
As a result, in 2000, an estimated 2.8 million people were at risk of contracting trachoma in Ghana alone, with women and children the most affected.
"Trachoma is a household problem," said Fuseini Kwadja, an ophthalmic nurse in Tamale, Ghana, who worked on the campaign to end the disease since its inception 20 years ago.
He describes how, in people's homes, he would see the prime environment for infections to spread. People would pull lashes out of a family member's eye and then did not wash their hands. Family members would share towels; flies would be resting on children's faces as discharge flowed down.
"People were blind because of ignorance," he said.
But the launch of a global control initiative in 1998 involving the World Health Organization, the Carter Center and Sightsavers, among others, set out to change this with a four-step strategy to make people aware but also to treat their infections -- and blindness.
Initiating global control
The strategy is called SAFE as it includes surgery, antibiotics, facial cleanliness and environmental improvement, namely the provision of water and sanitation.
Surgery could be done in people's homes and would treat those with inverted eyelashes by lifting their eyelids to prevent scarring. One inexpensive but powerful antibiotic, azithromycin, would be used to treat infections with a single dose. Pfizer, which makes azithromycin, donated the antibiotic to all affected regions globally and recently pledged to continue donating it until 2025.
Eventually, it was decided to give the antibiotic to everyone in affected villages globally, not just those infected, to truly rid that environment of the bacteria and prevent exposure to infections.
The goal was to eliminate the disease, not eradicate it. In this case, it meant bringing infections down to a low enough level that people don't go blind 20 years later from repeated exposure to infections.
Nurses had to be trained, drugs supplied and many affected children -- and communities -- found, Kwadja said. He recalls the case of a village chief he met who was becoming blinded by his infection and couldn't work. After Kwadja performed the surgery, the chief recovered and was able to tend to his farm and run his village.
Kwadja has now performed about 400 surgeries, he says.
Crucial too to keeping environments clean was the provision of latrines and boreholes by organizations such as World Vision International.
Ghana's government "put an emphasis on building safe and accessible water sources and latrines," Bush said, adding that in regions such as northern Ghana, animals represent wealth and are kept close to home to ensure their safety, meaning their excretions were also close by -- and so were disease-spreading flies.
Kwadja also recalls women who could not look after their children or their homes due to the pain every time they blinked. Treatment soon changed that.
After many cases like these, both in Ghana and more globally, the burden of the disease is finally being flipped.
Twenty years after efforts began to fight this leading cause of infectious blindness, teams are seeing remarkable and continuous progress.
"Communities are happier," Kwadja said, adding that when he returns to the affected villages today, he sees people smiling and pain-free, with fresh-faced children.
"Ghana is a success story," said David Mabey, professor of communicable diseases at the London School of Hygiene and Tropical Medicine. Mabey believes the general commitment to growth and improvement by a committed Ghanaian Ministry of Health has helped the country prosper. It is "very organized."
Mabey has worked on trachoma control for more than 30 years, particularly in Gambia, where he believes elimination will come next. "They have reached elimination but have not yet filed the paperwork to WHO."
China, Iran, Myanmar and Iran are also believed to have reached their targets, according to Sightsavers.
Mabey hopes elimination will be a rolling trend across the continent -- and globally -- but fears that the persistence of trachoma in unstable regions, such as Northern Nigeria and South Sudan, will prove challenging.
Mabey also stresses that the target in all countries is elimination, not eradication, meaning workers are not looking to end the infections altogether, just to make them low enough that's the issue is not a public health concern.
Bush recently conducted a drug distribution effort in Yemen, which also faces challenges in terms of access and security, and while coverage was good, "the challenge will be to keep that going," he said.
"Getting to the end of the program is really quite complex," Bush said. The final challenge will be the high-risk regions. But he believes that blindness can be ended in all affected countries.
"To end it globally, we have to work in those areas," he said. "It is all totally avoidable blindness."
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