Researcher Padma Gulur, MD, Duke University School of Medicine. Photo courtesy of Jim Rogalski

DURHAM, N.C.—New research by Padma Gulur, MD, a professor of anesthesiology and population health at Duke University School of Medicine, has bolstered a bright idea about pain management: green light exposure. The idea is young, and benefits are far from conclusive, but her work, and that of a handful of others, has revealed the potential of green light exposure as an affordable treatment with few side effects or risk of addiction, according to a recent article by Shantell M. Kirkendoll, a senior science writer and editor for the School of Medicine’s Office of Strategic Communications.

As Kirkendoll reported, Gulur’s research team studied 34 fibromyalgia patients who were randomized to wear various shades of eyeglasses four hours a day for two weeks: 10 patients wore blue eyeglasses, 12 wore clear eyeglasses, and 12 wore green eyeglasses. Patients who wore green eyeglasses were the only group with a majority of subjects having a decline in anxiety scores, and there was a statistically significant difference in the fear question in particular.
 
“We found that although their pain scores remained the same, those who wore the green eyeglasses showed higher odds of a 10 percent decline in opioid use, demonstrating that their pain was adequately controlled,” Gulur said of study results, which she presented this fall at a conference for the American Society of Anesthesiologists.
 
Researchers used commercially available green eyeglasses. Even though they looked the same, each was tested with a spectrometer before and after the study to determine which wavelength of green light each produced. “What stood out for us was almost all the patients who got green glasses in the randomization didn't want to give them back,” Gulur said.
 
The green wavelength ranges from 495 to 570 or so, she explained. Rather than the middle, or peak, “the wavelengths that were helping folks were on either end of that spectrum. Some people responded to much lower wavelengths, between the 490s to 510s, and the others responded to the higher wavelengths,” she said.
 
Larger studies that assess green light exposure on different chronic pain conditions are in store, according to Kirkendoll’s report. She noted that there’s also interest in the dose effect, narrowing down which wavelengths are the most effective so shorter exposures may be beneficial.
 
“Even more importantly we want to learn the mechanism,” Gulur said. “What’s doing this? So we’re planning some FMRI studies to try and understand what lights up (in the brain) when people are exposed to green light and get pain relief. There’s a lot more to be done, and we’re very excited about it.”