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NEW YORK (Reuters Health) - For many children in poor nations, a simple pair of glasses can be out of reach. But a new study suggests relatively cheap specs that people can adjust themselves hold some promise.
The study, reported in the journal Ophthalmology, looked at the usefulness of "self-refracting" glasses for adolescents with vision problems, mostly nearsightedness.
The glasses are designed so that the wearer can adjust them to the right strength without the need for eye professionals, who are scarce in developing parts of the world. In parts of sub-Saharan Africa, for example, there is just one optometrist for every 1 million people.
Made under the name Adspecs, the glasses are already in use. About 30,000 adults in developing nations have received them so far, according to the Center for Vision in the Developing World -- a group directed by Adspecs inventor Dr. Joshua D. Silver, a physicist at Oxford University in the UK.
But it hadn't been clear whether children and teenagers could feasibly use the specs. So in the new study, Silver and colleagues in China, the UK and U.S. had 554 Chinese students aged 12 to 17 years try them out.
The researchers compared the students' ability to self-correct their vision -- under the supervision of their teachers, who had been shown how to use the glasses -- against the results of a professional eye exam.
The adjustable glasses work via special lenses made of a clear membrane filled with silicon oil and held between two plastic discs. The wearer can change the amount of oil in the lenses using a removable syringe and dial that attach to the glasses' frame. Adding or removing oil changes the curvature of the lenses, which alters their strength.
Among kids in the current study, just over 92 percent were able to correct their nearsightedness using the glasses. That compared with a nearly 100-percent rate when the students were given professional eye exams.
"What we have proven is the basic principle," said Silver in an e-mail to Reuters Health. "The large majority of teenaged children in an area where poor vision from uncorrected refractive error is common can achieve vision sufficient to meet the demands of the classroom."
But many questions remain, the researchers say -- including how well the glasses would work for children in the real world, over the long term.
The specs also have their limits. For example, they cannot correct astigmatism, a common eye problem that is usually mild but can cause blurred vision in some cases. Nor are they known for their stylish looks: They are large, round, thick-framed and vaguely Harry Potter-esque -- although Silver's Center for Vision says the aesthetics should improve as the technology does.
And that is a major barrier to the glasses being put into wide use for now, according to Dr. Thomas S. Shane, an eye doctor with Bascom Palmer Eye Institute in Miami who was not involved in the study.
"The obstacle we'd have is getting kids to wear them," Shane said. "They're big, they're bulky, they're not stylish."
For the adjustable glasses to become everyday specs, they will need to be made considerably lighter and more attractive, according to Shane, who has been involved in projects to get vision screening and inexpensive, ready-made eyeglasses to people in Haiti and Belize.
However, Shane told Reuters Health, the adjustable glasses could offer a simple, cheap way to assess kids' vision and determine the level of correction they need. Right now, one way of doing that in the developing world is with portable devices called auto-refractors.
But auto-refractors are expensive and require someone trained in using them. Adspecs, by contrast, are $19 per pair, and can apparently be used by kids as young as 12.
"I think the best thing to come from this study is that it's feasible for kids to use these as a sort of 'field refractor,'" Shane said.
He and his colleagues at Bascom are beginning a study where they will have people use the adjustable glasses to self-correct their own vision, then give them inexpensive ready-made glasses based on those measurements.
While many people in wealthier nations see eyeglasses as a basic commodity, they are scarce in other parts of the world.
It's estimated that about 150 million people worldwide have impaired vision but no access to glasses. And 90 percent of those people live in developing nations, Shane noted. (Impaired vision means vision poor enough that, in the U.S., you could not drive without corrective lenses.)
Silver has said his goal is to get the Adspecs price down to $1 a pair, and distribute 1 billion pairs worldwide by 2020.
"A key part of further work will be the creation and test of designs which are appealing to kids and well-suited to the rough-and-tumble of daily life," he said.
SOURCE: bit.ly/hXHVoU Ophthalmology, online January 12, 2011.