Green Light Therapy for Migraine
"Researchers Explore A Drug-Free Idea To Relieve Chronic Pain: Green Light" declared the headline of an NPR story published in December.1 Like so many news articles on migraine, it seemed interesting but left me with a ton of questions.
I dug around online and found the listing for the clinical trial, which spurred even more questions.2 So I went to the source.
Dr. Mohab Ibrahim, the study’s lead researcher, is an anesthesiologist and pain specialist at the University of Arizona. He was kind enough to spend 40 minutes answering my questions about the study.3 Here’s what I learned.
Green light therapy for migraine research
Before you get too excited about green light therapy as your next treatment, know that while the research is promising, it is in the early stages. The migraine study, though nearly finished, is still in progress as of January 2020, and the findings have yet to be written up, much less published. And further research is needed to optimize the therapy so it’s practical for people to fit into their lives.
What is it like to experience green light therapy?
Participants in the study were instructed to sit in a dark room with the green light on for one to two hours every evening. While they could do anything they wanted while the light was on, the room had to otherwise be completely dark—that means no light from screens, like televisions, phones, tablets, or e-readers.
Don't stare directly into the light
Participants were told to not stare directly into light or even look straight at it, but to keep their eyes open the whole time. They were encouraged to do something engaging, like have a conversation, read, or do a hobby like knitting while sitting under the light.
This may sound like a long time to be in a dim room when you don’t have a migraine attack. Keep in mind that this was the first study, so it was getting a baseline idea of the treatment.
How much green light should a person be exposed to?
Dr. Ibrahim and his team are planning future studies to see how to optimize green light exposure. These will look at how long a person really needs to be exposed to green light, if exposure needs to be every day or if it can be less frequent, if green light needs to be the only light in the room or if it can be combined with other light sources, and if glasses might be another way to get exposed to this specific wavelength of light.
Is green light therapy beneficial for migraine?
Dr. Ibrahim said the study participants with migraine “saw a significant decrease in the number of headaches per month and the intensity of their headaches also significantly decreased, maybe by 60%.” With fewer than 30 participants, this is a relatively small study. Still, these are promising data for such a low-risk treatment.
Is green light a preventive or acute treatment?
In this research, green light was studied as a preventive treatment out of respect for photophobia. Based on the earlier rat studies that Dr. Ibrahim and his team did, they believe that green light is therapeutic when it comes in through the eyes.4 (There’s a possibility the light could be absorbed through the skin, but the rat studies indicate it’s through the eyes.)
Using green light between migraine attacks
So to study the effect of green light on migraine, participants’ eyes need to be open when they’re exposed to the light. As you can imagine, that may be uncomfortable during an active migraine attack, so researchers instructed participants to use the light only between attacks.
Are there known side effects of green light therapy?
Dr. Ibrahim said that no one has reported any side effects in his studies. He did say he heard from someone who read the paper on the rat study of green light therapy and built his own setup to try. That person looked directly at the green light for four to eight hours a day. While his diffuse pain improved, he developed eye pain. So, like with any treatment, green light therapy needs to used carefully and more isn’t necessarily better.
Can I buy a green light and try the therapy today?
Knowing the desperation of wanting relief from migraine, I asked Dr. Ibrahim what he would tell a person with migraine who wanted to try green light therapy right now. He first advised getting a diagnosis to be sure you have migraine and not another disorder, then talking with your doctor before trying it on your own. (If you have eye problems, he also said to talk with an ophthalmologist to see if the green light could interfere with an underlying issue.)
The study used low-intensity green LEDs at a wavelength of 525nm (+/- 10nm). (All the technical details of the light used will be included when the study is published.) Dr. Ibrahim warned against websites charging exorbitant prices for lights they say are therapeutic. “Light therapy is very cheap. Very cheap,” he said, so you should be able to access the treatment at a low cost when it becomes available.
What happens next?
Like with so many migraine treatments reported in the media, green light therapy isn’t quite ready for prime time. But the research is promising. Any inexpensive treatment that has few side effects is definitely worth keeping an eye on.
Can you tell when a migraine attack is coming?