Many headache and migraine sufferers know the excruciating pain that light exposure can bring. All you want is to burrow into a deep dark hole until the pain subsides.
Photophobia: an abnormal sensitivity to light; discomfort in bright light; derived from the latin “photo” meaning light and “phobia” meaning fear.
Often, painkillers aren’t even enough to dull the senses, so you resign to being alone in your dark room unable to get anything done. Your days are pain-filled, lethargic, and you start to feel like all hope is lost.
Turns out, only certain colors contained in the visible spectrum of light make your headache pain worse. New emerging science is shedding *light* (full pun intended) on the benefits of exposure to green light to help with headaches.
Green Light Therapy for Headaches
The green light we’re interested in is around 525 nanometers. A nice bright, vibrant green! Smack dab in the middle of the visible light spectrum (more or less).
Recent studies out of Harvard and the University of Arizona show that exposure to green light reduces and even prevents the perception of pain in participants with migraines, headaches, fibromyalgia, and other chronic pain conditions.
Another international study shows that both blue and red light stimulates our retinal pathways and set our system out of balance. Green – which is right in the middle – does not have this effect and thus we stay in equilibrium – no reaction, no pain.
The only kicker is that this green light therapy really only works if you stay consistent. Like a good workout routine. And it doesn’t always work for everyone. But if you’re looking for a chemical and side-effect-free pain reliever, this does work!
Looking for a green light therapy device? Check out our article The Best Green Lights for Migraines and Headaches to find the device that works best for you!
What is Photophobia?
Photophobia is the abnormal sensitivity to light often associated with headaches, migraines, and other ocular pain. It’s the discomfort and sometimes outright pain you feel when in a bright room or outside on a sunny day.
Quick background info: This happens because when pain receptors in your body are activated, they send signals to your brain alerting you that something has gone wrong. Like Mayday! Mayday! Danger Will Robinson!
In the case of photophobia, a study supported by the National Headache Foundation shows that light-activated cells in your eyes known as ipRGCs (intrinsically-photosensitive retinal ganglion cells) can act as pain receptors for light.
When these cells are exposed to high-intensity light, they signal your thalamus which then signals your cortex alerting your brain that there is something stressful going on. The stress response induces pain resulting in photophobia.
In normal instances, we can just squint our eyes or divert our gaze away from the bright light source. However, when we already experience chronic pain or have a headache/migraine, that pain is elevated and our bodies can’t cope as well.
Previously accepted knowledge of the connection between the eyes and the brain believed that it was through the optic nerve that all light data was relayed, but this new discovery of ipRGCs has turned that on its head.
It’s so weird because a study on blind people experiencing migraines shows that even with the optic nerve severed, or other disease damage in place, these patients still experience photophobia. As long as they still have eyeballs, this occurs.
So that’s where the ipRGCs become so important. They exist on your eyeball itself and can transmit light information directly to your brain. When the eyeballs are removed, these patients do not experience photophobia.
How Different Color Lights Affect Pain Perception
If you’ve stuck around this long, we might as well dive a little deeper into how these little light receptors in our eyeballs are affected by other colors. Mostly because I find this super fascinating so now you have to come along for the ride.
Since each color in the visible light spectrum is associated with wavelengths of a certain frequency, they have different effects on our bodies. Some colors are considered more “stressful” or “reactive” than others.
Surprisingly it’s not just a matter of higher-frequency wavelengths being more reactive than lower-frequency wavelengths. Apparently, you can’t think of it in a linear fashion, it’s more of an upside-down bell curve! Who knew?!
As you can see, the folks at Harvard were able to gather data to show how patients evaluated their pain after exposure to different color lights.
Can you see the upside-down bell curve trend?
It appears blue as a color increases pain perception the most, whereas red when at higher intensities creates a bit more pain.
Obviously green was the least reactive and it appears to be by an incredible margin.
White light contains all of the colors in the visible spectrum so there is no escaping painful wavelengths. This kind of light is emitted from the sun, obviously, but also by many standard light bulbs and LEDs.
The sun actually produces quite an even distribution of all the visible colors, but LEDs have a huge blue spike and then a hump of the colors that remain. This makes LEDs much worse on your eyes – we’ll go over blue light more in a moment.
So when you go outside, or if you’ve brought the sun inside your home, and you already have a headache forming, be prepared for pain. If you don’t have any green light available, just turn it all off and stay in your cave until you feel better.
If your room isn’t quite dark enough to keep the photophobia at bay, check out our article with helpful tips and tricks to black out your bedroom.
Most of you probably already know about the power of blue light. It has become very popular in treating SAD (seasonal affective disorder) and realigning your circadian rhythm.
How Can Blue Light Affect Your Circadian Rhythm?
Since the wavelengths are shorter, they have a higher frequency which your brain interprets as stressful. This reaction wakes you up, or keeps you awake and alert, which too much of can bring on photophobia and more painful migraines.
If you work on a computer a lot or you find yourself on your phone into the night, I highly recommend blue blockers. If you’re a nighttime doom scroller, consider enabling the blue-blocking capabilities on your iPhone at least an hour before bedtime.
This was an interesting one. Many in the health space have heard of red light therapy for accelerated healing of wounds or other injuries. So why would this light, known to heal, also cause pain?
In a study of rats, red light was used to actually induce pain responses. Not that it created the sensation of pain but it certainly seems to heighten their sensitivity.
This study used red light (660 nm) and found after exposure for 8 hours a day for 5 days, rats withdrew their paws faster from a painful stimulus.
Lower latency = faster reaction.
We can also see these same researchers found green light exposure increased the latency so this further demonstrates the magic of green light for pain.
To be fair, this was a study done in rats – not humans. But we have seen in other studies, such as the Harvard mentioned above, that red light pain perception was pretty much on par with blue.
There was also another study done in the Journal of Clinical Neuroscience where two different light-blocking lenses were used – one to filter blue light and another to filter red – participants’ pain scores were measured after a time using one or the other.
Surprisingly, both lenses decreased participants’ perception of pain quite equally.
The researchers were not expecting this, but it demonstrates how red light does have an effect on enhancing pain sensitivity in humans.
As we have shown, a low-intensity narrow-band green light is highly effective at decreasing the perception of pain in humans. There are no side effects and it might not work for everyone equally, but it just might be the miracle you’re looking for.
If you suffer from chronic pain – whether in the form of headaches, migraines, fibromyalgia, irritable bowel, etc – and you want to avoid medications with nasty side effects, I highly recommend green light therapy lamps or a pair of migraine glasses.