In the ongoing search for effective acute and chronic pain management that reduces reliance on opioids, Duke researchers are examining the pain-relieving potential of a novel, nonpharmacological treatment: the antinociceptive effect of green-spectrum light exposure.

“The medical community has recognized that pain is helped the most with a multimodal approach,” says Padma Gulur, MD, pain medicine specialist, director of pain management strategy and opioid surveillance for Duke University Health System, and lead investigator for the NIH-funded, two-year clinical trial. “Medications alone rarely control pain fully; you have to look for additional strategies to try and help. The bottom line is that we need lots of tools to manage pain.”

Gulur, who is an internationally recognized expert in the field of pain management, explains that visually mediated cognitive and biological effects of specific color ranges of light are broadly recognized in areas of affect and circadian rhythm, but similar effects on pain perception are less understood.

“In our study, we’re comparing people who are exposed to different wavelengths of blue, clear, and green light to see which one is beneficial by measuring participants’ pain relief and response. We’ve had early results in pilot studies where green seems to help, so now we’re studying the role of the visual cortex in those signals, understanding which wavelengths are particularly useful, and looking at the reasons for this phenomenon,” Gulur says.

“Dr. Gulur’s pioneering clinical protocol will help us understand translationally relevant aspects of fascinating but also puzzling basic science discoveries of how light—especially green light—can attenuate pain, which neural circuits might be involved, and which individual predisposing factors we can identify toward personalized medicine,” says Wolfgang B. Liedtke, MD, PhD, a Duke neurologist and pain medicine specialist who is in charge of two outpatient clinics: one in neurology/headache pain, and one in innovative pain therapy.

With a vision for eventually developing a commercially available wearable technology based on the results of the study, Gulur acknowledges the challenges to come. “How do you feasibly deliver green light to people in a way that doesn’t interfere with their quality of life and increases their compliance with the therapy?” she says. “We can’t change to green screens in every environment, nor can we ask people to sit in rooms with ambient green light for long periods of time. So, part of our study is about refining the science—identifying ways in which we can target the visual cortex in the brain and personalize the experience for patients.”

The light exposure study is a continuation of Gulur’s research goals of finding additional nonpharmaceutical avenues for pain management, including nutritional and musical interventions.

“The possible ramifications of this study are huge,” says Gulur. “We have such a tremendous burden of pain management in the nation now that even if we see 50% of patients benefit from this therapy, then already it becomes something worth trying to give them a better quality of life.”

“As someone who takes care of many patients suffering from chronic pain who are in need of improved treatment, I am looking forward to the study’s results,” Liedtke adds.