Hundreds of millions of people suffer from impaired vision for a myriad of reasons, including diabetes, cataracts and infections. But the largest percentage, an estimated 158 million, are coping with uncorrected refractive error: vision loss due to inadequate medical care and lack of corrective lenses. Of those suffering from URE, 8.7 million are completely blind. The rest contend with moderate to severe visual impairment.
Lisa Maree Williams, Getty Images
About 158 million people suffer from impaired vision because of a lack of adequate medical care and corrective lenses. Researchers say vision loss can have a massive economic impact, particularly in developing countries. Here, a nurse examines a young student in Bali, Indonesia.
Those figures were tabulated by economists at the Johns Hopkins Bloomberg School of Public Health, who've been working on determining the global economic impact of vision impairment.
"What we're talking about here is impaired function, learning ability, work skills and social function," Kevin Frick, one of the economists working on the project, told AOL News. "It's a massive worldwide problem."
For children suffering from URE, something as simple as reading a chalkboard can be impossible. That affects educational progress, job prospects and lifelong economic contribution.
Adults might be unable to drive or perform a handful of vital work skills, especially artisanal tasks, like sewing, that are more likely to be practiced as full-time employment in developing regions.
The impact is "in the hundreds of billions," Frick estimates, though he acknowledges that it's impossible to pin down a precise figure.
"It's a tricky business because different kinds of vision loss affect different abilities," he said. "But in all our estimates, we try to be as conservative as possible."
In a paper published last year by the World Health Organization, Frick and his colleagues estimated that current rates of vision loss will cost the global economy nearly $270 billion, after adjusting for country-specific labor trends and employment statistics.
That translates to $1,000 lost for every person who needs glasses but can't get a properly prescribed pair, the research concluded.
And the economic consequences of vision loss aren't a problem only for developing nations. In the U.S., the number of people with uncorrected vision loss is far from negligible. A 2002 study at Johns Hopkins, published in The Journal of the American Medical Association, estimated that 14 million Americans suffer from visual impairment that hasn't been remedied with corrective lenses.
Of course, initiatives to provide corrective eye wear to those who need it have been ongoing for decades. But Frick and his colleagues are wary of donation-based programs.
"It's essentially unethical to offer someone a pair of glasses and then leave," Frick said. "Vision correction requires long-term care."
Donated glasses often aren't the right prescriptive match for the recipient and can cause more problems than they solve. Instead, Frick is working on a plan to train locals as vision technicians so they can perform simple eye exams and offer prescriptions. Trained optometrists would be available for more rigorous screenings, and glasses would be produced locally or sourced from other countries.
A program based in specific locales would offer ongoing medical care in native languages. And Frick anticipates that despite the initial expense, such a program would also be less expensive than the ongoing economic damage caused by widespread vision impairment.
"To eliminate this problem, how much would we really have to spend?" he asked. "It's a matter of ... offering a long-term solution that will benefit generations."
Researchers also have their eye on the idea of self-adjusting glasses, which use silicone oil to move lenses in or out. For around $19 a pair, individuals could then tailor their prescription.
The glasses, called "AdSpecs," were invented by British entrepreneur Joshua Silver. They are being distributed through his nonprofit, Global Vision 2020. The organization hopes to hand out a billion pairs within the decade.
For Frick, the idea is more effective than donating used glasses but remains a temporary Band-Aid. "Nothing compares to training and a precise prescription," he said.