According to the Migraine Research Foundation, around 39 million Americans suffer from migraines. Globally, the number is over one billion. One common trigger for migraine sufferers is photophobia or light sensitivity.

Bright or flashing lights may trigger migraines, particularly in those susceptible to them. So it may surprise you to know that a form of light therapy may prove useful in reducing the number and severity of migraine attacks.

Green light therapy has been studied for several years to treat migraines and reduce pain in conditions such as fibromyalgia. As of yet, there is no definitive answer to whether green light therapy is helpful, but some studies have shown promise.

Recent Studies about Green Light Therapy

In 2011, researchers discovered that blind migraineurs could feel pain upon exposure to blue light. In turn, this finding prompted scientists to consider whether blocking specific spectra of light could help reduce light sensitivity. 

In a study published in 2016 in Brain, a respected neurological journal, Harvard Medical School researchers at Beth Israel Deaconess Medical Center reported reduced headache severity in a group of migraine sufferers when they were exposed to a narrow band of green light. Surprisingly, they found the reduction to be significant.

Raimi Burstein, the HMS John Hedley-Whyte Professor of Anaesthesia at Beth Israel Deaconess and lead author of the study, stated, "More than 80 percent of migraine attacks are associated with and exacerbated by light sensitivity, leading many migraine sufferers to seek the comfort of darkness and isolate themselves from work, family and everyday activities.”

In the same study, 20% of participants reported green light actually reduced migraine pain. 

During the study, participants were exposed to blue, red, white, amber, and green light. The researchers discovered that all colors generated stronger electrical signals in the retina at the back of the eye and the cerebral cortex than green light.

In fact, nearly 80% of migraine patients experienced an exacerbation of their symptoms when exposed to light spectra other than green. In comparison, green light created problems only 40% of the time. Also, exposure to most light initiated headaches about 16% of the time while green light triggered a migraine only 3% of the time. 

In another study published in the journal Pain in 2017, researchers exposed three groups of rats with neuropathic pain to green light in various ways.

• One group was bathed in green light from LED strips.
• A second group was fitted with opaque contact lenses that blocked green light.
• The third group was exposed to room light while wearing contact lenses that allowed only the green spectrum to pass through.

The groups exposed to green light showed pain relief benefits for up to four days after the last exposure. Only the group that had no exposure to green light showed no benefit. None of the rats showed any side effects from the exposure.

More research is needed, but Dr. Mohab Ibrahim, the lead researcher on a clinical trial at the University of Arizona, said that their 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%.” 

What Is Green Light Therapy?

All spectra of light generate electrical signals in the retina and the cortex. Red and blue generate the largest signals, while green generates the smallest. In this case, it's reasonable to believe green light may be less bothersome to those with photophobia.   

Green light therapy provided by exposing a patient to a specific narrow band of green light from a special lamp may reduce the number and severity of attacks. However, all other light was filtered out. 

Effectiveness hasn’t been demonstrated definitively, and there are no clear guidelines for providing green light therapy. It seems to work best for reducing the dosage of preventative or abortive medications instead of providing complete pain relief and eliminating any need for drugs. 

Your physician may be able to shed some light on green therapy (pun unintended). And with no noted side effects, you could certainly try it by purchasing a green light lamp. Just don’t spend too much money since the true effectiveness hasn’t been proven.

Of course, this treatment is attractive to patients because it’s non-invasive, inexpensive, and patient-controlled.

How to Use Green Light Therapy

Again, there are no studies showing a definitive use for green light therapy or that it relieves migraines for everyone. However, patients are interested. The need is to set some parameters.

One of the studies used low-intensity green LEDs with a wavelength of 525 nm +/- 10 nm. Often the treatment is purely preventative since nothing is showing green light reduces pain during an attack.

Participants in a study were instructed to sit in a dark room with a green light for one to two hours every evening. They could do anything they wanted while the light was on except watch TV, use a computer monitor, tablet, or smartphone. They were not allowed to use e-readers.

They were not to look directly into the green light source but to keep their eyes open. They could do other activities, like reading books or magazines, knitting, or talking to someone else.

Studies continue to try to determine how long the exposure needs to be, whether patients would need to be exposed to the green light every day, and whether the green light can be the only one in the room. It’s also too soon to know if glasses or contact lenses tinted green would be beneficial.

So far, all the study groups have been small. To prove effectiveness, researchers need a large-scale, double-blind study using patients diagnosed with migraine. They would need to figure out how to provide the light therapy and answer the questions of whether other lights can be on in the room. 

At this point, we only have small studies in rats and humans that hint at migraine relief through green light exposure. On the bright side (sorry!), there are no side effects to worry about if patients want to try. 

At the Migraine Relief Center, we want to keep you updated on possible treatments out there that may help. As always, we are happy to talk with you about a range of therapies and treatments for your migraines.