How Light Therapy May Ease Your Migraines

Green Light May Improve and Blue Light May Worsen Migraine Pain

Do Green or Blue Light Rays Affect Your Migraines?
Do Green or Blue Light Rays Affect Your Migraines?. Paper Boat Creative/Getty Images

Light therapy is a successful treatment for seasonal affective disorder and some skin conditions like psoriasis. Researchers now believe that light therapy could also be useful for easing migraines. This is an emerging idea, but exciting nonetheless.

To understand how light therapy may soothe your migraines, let's delve further into the link between light and migraine attacks.

What Is Light Sensitivity in Migraines?

Light sensitivity (photophobia) is a common symptom associated with migraines.

In fact, research suggests that it affects approximately 80 percent of migraineurs. While it is generally not as debilitating as the actual migraine pain, it can significantly limit a person's ability to function. It can also promote isolation, as a person seeks out the comfort of darkness until their migraine is relieved.

What Does it Mean to be Light Sensitive for a Migraineur?

Light sensitivity means that light, especially bright light, can hurt a person's eyes. In response, a person will often instinctively squint, put sunglasses on, or put their hand above their eyes to provide shade.

For migraineurs, it also means that exposure to light during a migraine attack can worsen the pain of their headache. 

How Does Light Exposure Affect Migraine Pain Perception?

Researchers believe that receptors on the retina of the eye detect light and in response transmit photic signals to nerve cells called trigeminovascular neurons.

These signals travel from the retina to the trigeminovascular neurons via the optic nerve. Eventually, the signals travel to the cerebral cortex (the brain) where migraine pain is perceived.

How Does Blue Light Worsen Migraine Pain?

Sunlight is composed of red, orange, yellow, green, blue, indigo, and violet light rays that when combined makes white light.

Blue light has a short wavelength and a lot of energy, as compared to other rays of light like red, which has a longer wavelength and less energy. That being said, blue light often makes up a larger component of white light, which can expose the eye to more energy (this can be damaging).

Sources of blue light include sunlight (the biggest source), cell phones, computer monitors, tablet screens, flat screen LED televisions, LED lights, and compact fluorescent light bulbs. In other words, blue light is everywhere.

Receptors in the retina of a person's eye (called photoreceptors) are most sensitive to blue light, which is why scientists believe blue light exposure (emitted by many inside lights or sunlight) can worsen migraine pain. In fact, these receptors are so sensitive to blue light that even some people who are legally blind can detect blue light (they can see "light" but not "images"), and it can worsen their migraine attacks too—a fascinating phenomenon.

Is There a Light Ray That Can Ease Migraines?

Researchers believe that blue light can worsen migraine attacks, which is why doctors often recommend migraineurs rest in a dark room during an attack.

But is there a colored light ray than can ease migraines? Possibly.

A 2016 study in Brain found that exposure to green light significantly decreased light sensitivity in a small group of migraineurs. For some of the migraineurs (20 percent), exposure to green light also reduced migraine headache pain.

How did the researchers come to these results? In this study, forty-one migraineurs undergoing an acute migraine attack were exposed to five series of light stimulation:

  • white light
  • blue light
  • green light
  • amber light
  • red light

Each exposure consisted of three minutes of complete darkness followed by a gradual increase in light intensity. At the end of each light exposure, the light was turned off, and the participants were given time for their headache intensity to return to baseline.

The participants were assessed on whether the color of light affected their migraine headache intensity and headache location, as compared to headache intensity and location when in the dark (considered baseline).

Of the participants, almost 80 percent reported a greater headache intensity with all colored light exposure (as compared to darkness) except green. In fact, about 20 percent noted a lesser headache intensity with green light exposure.

In taking a closer look, the researchers did a comparison between the colors. They found that pain ratings (done on a scale of 0 to 10) had smaller changes when going from darkness to green light, as compared to white, blue, amber, and red light exposure, where there was a significant increase in pain ratings.

Regarding headache location, more participants noted a spread of their headache (for example, from the back of the head to the front or from the right to left side of the head) with blue, red, and amber light exposure, than with white or green light exposure.

What Do These Results Mean?

It is important to look at the big picture here. This study suggests that green light at the very minimum is the color of light that is least likely to worsen migraine headache pain. At the very maximum, green light exposure may soothe migraine headache pain.

A Word From Verywell

While light therapy is an inexpensive and simple way to complement traditional migraine therapies, more research needs to be done.  While the study in Brain is a good start, larger studies are needed, especially ones that utilize devices that either specifically emit green light and/or block blue light.

Sources:

American Optometric Association.(December 2014). Light and Eye Damage.

Choi JY, Oh K, Kim BJ, Chung CS, Koh SB, Park KW. Usefulness of a photophobia questionnaire in patients with migraineCephalalgia. 2009 Sep;29(9):953-9.

Noseda R et al. Migraine photophobia originating in cone-driven retinal pathways. Brain. 2016 Jul;139(Pt 7):1971-86.

Noseda R et al. A neural mechanism for exacerbation of headache by light. Nat Neurosci 2010;13:239-45.

Prevent Blindness. (April 2016). Blue Light and Your Eyes. 

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