Eyeglasses boosted the standardized test scores of rural Chinese schoolchildren as much as 18 percent in just six months, according to a large-scale, ongoing study led by Stanford researchers.

"The evidence is overwhelming," said Scott Rozelle, co-director of the Rural Education Action Program (REAP), a coalition of Chinese universities and Stanford's Freeman Spogli Institute for International Studies that works to improve education and health in rural China.

The initial test scores for nearsighted students hovered around 68 percent. After receiving glasses, average scores soared to 86 percent. "You do these simple interventions and a child's whole life changes," Rozelle said. "It's fantastic."

REAP scholars partnered with Chinese ophthalmologists and scores of graduate students to orchestrate the massive project, the first to examine vision problems in rural China.

In 2012 and 2013, the team screened the vision of approximately 20,000 fourth and fifth graders in rural Shaanxi and Gansu provinces and doled out more than 4,000 pairs of eyeglasses. They discovered that 25 percent of the students were nearsighted, but only one in seven of those nearsighted students had the glasses they needed.

"There's a huge amount of unmet need," said Matthew Boswell, a REAP project manager based at Stanford.

The results may seem intuitive. Yet, helping the millions of nearsighted children in rural China is anything but easy, the REAP team discovered. Few of these rural children (and adults) know they are nearsighted – the world, to them, is naturally blurry. In addition, eye doctors are concentrated in the populous coastal corridors or regional "county towns," often dozens of miles by bus from the homes of rural Chinese families, Boswell said.

Basic eyeglasses cost between 200 and 500 yuan ($30 to $80), a price out of reach for many, he said.

The researchers also struggled to counter pervasive superstitions about eyeglasses.

For example, many rural Chinese residents believe that glasses make children's' vision deteriorate, relying on the observation that vision generally worsens with age, Boswell said. In addition, many Chinese do "eye exercises" by rubbing their eyes, cheeks and temples each morning, a practice they believe improves vision, he said.

They also face political struggles: China's rural health care program doesn't pay for vision care. "We could tell health or education officials until we were blue in the face there was a high level of need for vision care in rural communities," Boswell said. "But if your findings are not attached to something they care about, it's hard to make them listen."

Hence the connection to the test scores, a highly valued measurement by Chinese policymakers. The REAP team taps its large network of Chinese academic collaborators to translate its research results into policy reform, a process that is often successful, Rozelle said.

REAP is currently analyzing alternative ways to boost the delivery and acceptance of eye care, Boswell said. The original study assigned nearsighted students into six groups.  Researchers gave one-third of the students glasses; one-third received a voucher to purchase glasses; and another third remained untreated. Then, half of the students in each group received training about the causes and treatments for vision problems.

The training failed to significantly affect whether students wore the glasses, Boswell said.  The students who had to invest time to acquire glasses using a voucher demonstrated similar usage rates as students who received free glasses, he said.

Among a variety of other initiatives currently underway, the REAP team is training Chinese teachers to conduct simple vision tests, Boswell said.

"It's an extreme feel–good example," Rozelle said. "You put the first pair of glasses on a kid … and then a huge smile lights up their face."

Becky Bach is a writer for the Stanford News Service.