Green Light for Pain Relief
On his way to the pharmacy to pick up pain relievers for a headache, Dr. Ibrahim passed Gene C. Reid Park in Tucson. Recalling how his brother eased headaches by sitting in his backyard, Dr. Ibrahim pulled over.
“Reid Park is probably one of the greenest areas of Tucson,” said Dr. Ibrahim, who also serves as medical director of the Comprehensive Center for Pain & Addiction at Banner-University Medical Center Phoenix in Arizona. “I spent a half hour or 40 minutes there, and my headache felt better.”
Being outdoors in a green space may be soothing for lots of reasons, like the quiet or the fresh air. But there’s also sunlight reflected off and shining through greenery. The experience inspired Dr. Ibrahim to take a closer look at the effects of green light on chronic pain.
In his 2021 study of 29 people with migraines, participants reported that, after daily exposure to green light for 10 weeks, the number of days per month when they had headaches fell from 7.9 to 2.4 for those who had episodic migraines and from 22.3 to 9.4 for those with chronic migraines. In another 2021 study, 21 people with fibromyalgia who had green light therapy for 10 weeks said their average, self-reported pain intensity fell from 8.4 to 4.9 on a 10-point scale used at the University of Arizona’s pain clinic.
Volunteers in both studies got their light therapy at home, switching on green LED lights while they listened to music, read a book, relaxed, or exercised for 1 or 2 hours daily. The lights were within their field of vision, but they did not look directly at them.
Dr. Ibrahim now has funding from the Department of Defense and Department of Veterans Affairs to find out why green light alters pain perception.
“What we know is that the visual system is connected to certain areas of the brain that also modulate pain,” he said. “We are trying to understand the connection.”
Padma Gulur, MD, a professor of anesthesiology and population health and director of Pain Management Strategy and Opioid Surveillance at Duke University, Durham, North Carolina, saw similar results in a 2023 study of 45 people with fibromyalgia. But instead of using a light source, volunteers wore glasses with clear, green, or blue lenses for 4 hours a day.
After 2 weeks, 33% in the green lens group reduced their use of opioids by 10% or more, compared with 11% in the blue lens group and 8% who wore clear lenses. Previous studies have found green light affects levels of the feel-good brain chemical serotonin and stimulates the body’s own opioid system, the authors noted.
“Green light helps your body control and reduce pain,” Dr. Gulur said. It “seems to help with pain relief by affecting the body’s natural pain management system. This effect appears to play a crucial role in antinociception — reducing the sensation of pain; antiallodynia — preventing normal, nonpainful stimuli from causing pain; and antihyperalgesia — reducing heightened sensitivity to pain.”
Light therapy could help pain patients reduce their dose of opioids or even forgo the drugs altogether, Dr. Gulur said. “It is our hope this will become a useful adjuvant therapy to manage pain.”
In the University of Arizona studies, some patients on green-light therapy stopped their medications completely. Even if they didn’t, other benefits appeared. “They had improved quality of life, decreased depression and anxiety, and improved sleep,” Dr. Ibrahim said.
But not just any green light or green-tinted glasses will work, both researchers said. “We have found there are specific frequencies of green light that give this benefit,” Dr. Gulur said. “OTC products may not be helpful for that reason.”
While Dr. Ibrahim said it could be possible for healthcare practitioners and consumers to consult his studies and put together an inexpensive green-light device at home while carefully following the protocol participants used in the studies , it would first be a good idea for patients to talk with their family doctor or a pain specialist.
“A headache is not always just a headache,” Dr. Ibrahim said. “It could be some other abnormality that needs diagnosis and treatment. If you have long-lasting pain or pain that’s getting worse, it’s always better to discuss it with your physician.”