NOEL KING, HOST:
Doctors often treat depression and seasonal affective disorder with light therapy. It's where patients are exposed to an artificial light source. Now some researchers are testing whether another kind of light therapy, one that relies on the color green, can help with chronic pain. Will Stone has the story.
WILL STONE, BYLINE: Ann Jones had tried everything short of surgery for her migraines, which have plagued her since she was a child.
ANN JONES: They have actually gotten worse in my old age.
STONE: To the point where Jones, who's 70, was up to 24 migraines a month.
JONES: It was pretty debilitating.
STONE: Then her doctor mentioned a study that was taking place in her hometown of Tucson, Ariz. Researchers were testing if daily exposure to green light could relieve chronic pain. Her initial thought...
JONES: This is going to be one more thing that doesn't work.
STONE: But she enrolled in the study anyways. Each day, she'd spend two hours in a dark room under the glow of a green LED light. For more than a month, she didn't notice much. Then a big shift - the migraines came less often and they weren't as intense.
JONES: I got to the point where I was having about four migraines a month, if that many. I felt like I'd just been cut free.
STONE: That outcome is what Dr. Mohab Ibrahim hopes for. He's the one leading the study.
MOHAB IBRAHIM: So you can decrease the intensity or increase it.
STONE: In his pain clinic at the University of Arizona, Ibrahim gives a quick demo of his device, a strip of green LED lights mounted onto a thin vertical stand. He likes the simplicity.
IBRAHIM: The most ideal drug or therapy is something that's safe, effective and affordable.
STONE: Still, it's an unlikely approach for Ibrahim. He's an anesthesiologist with a Ph.D. in pharmacology. Drugs are his tools.
IBRAHIM: There was a healthy dose of skepticism because it was kind of strange - why are you using light to treat pain?
STONE: Ibrahim says his interest started with his brother's headaches. Instead of taking medicine, he'd go to his garden and the migraines would subside. So Ibrahim's team at the University of Arizona ran some experiments on rats, and they discovered the animal's pain response decreased when exposed to green light.
IBRAHIM: And we were able to reproduce it over and over and over again.
STONE: Next, Ibrahim's team fitted tiny contact lenses in different colors on the rats. They found only the animals that could see green light had a drop in their pain response.
IBRAHIM: Whatever effect is happening is taking place through the visual system.
STONE: Ibrahim got funding from the National Institutes of Health for his research, and he's now studying how the treatment works on humans - people with chronic pain, nerve pain and migraines. His initial findings indicate the green light may be stimulating the body's natural opioid system, but he believes there are more pathways at work, too. Other researchers are looking into the connection between light and pain. An earlier study at Harvard Medical School found that green light is less likely to exacerbate a migraine compared to other colors. Those who treat migraines, like Dr. Mo Levin, are eager for a new, non-invasive approach.
MO LEVIN: It's a happy thought. I hope it works.
STONE: Levin is director of the Headache Center at the University of California, San Francisco. He's intrigued by the science, but...
LEVIN: It seems like a stretch to me. I don't think we really have strong information that suggests that the exposure to green light is somehow highly beneficial for people with migraines.
STONE: Still, some people aren't waiting for all the data. Dwayne Lowe is a chiropractor with the Department of Veterans Affairs in Colorado. After reading the research, he decided to order some green glasses online for his chronic pain patients.
DWAYNE LOWE: After a very short period of time, many of the patients just noted that their headache felt better and seemed to be shorter.
STONE: He knows it's experimental, but the glasses are cheap and without side effects. Back in Arizona, Dr. Ibrahim says early results show promise. In his human study of about 25 patients, the average person experienced a 60% decrease in the intensity of migraines and a drop from 20 migraines a month to about six.
IBRAHIM: The implications can be really significant if it works for other conditions as well.
STONE: Ibrahim's patient Ann Jones says her migraines came back when she stopped doing the treatment.
JONES: I made a commitment to go back to the green lights, and the very next day, I did not have a migraine.
STONE: The only downside, she says, is finding the time to spend in a dark room with a green light for company. And that's a side effect she can live with.
For NPR News, I'm Will Stone.
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