Migraine: Get Out of the Red Light District

28. June 2016
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Migraine is often associated with increased sensitivity to light. One research team has now discovered that white, red and blue light increase the pain, whereas green light can ameliorate it. Glasses with special filters could relieve migraine pain.

Migraine is a common condition: approximately 10 to 15 percent of the population are affected by it, women three times as often as men. Severe headaches are often accompanied by increased sensitivity to light, sounds or smells. “More than 80 percent of migraine attacks are associated with an increased sensitivity to light – and they are simultaneously amplified by light sensitivity”, explains Rami Burstein, specialist in pain and anaesthesia at Beth Israel Deaconess Medical Center in Boston (USA). Many sufferers themselves when in normal lighting conditions go looking for sunglasses or retreat to darkened rooms. “This leads to significant impairments in many contexts: at work, in social relations and in everyday activities”, says Burstein.

Yet not every type of brightness has the same effect. A recent study [Paywall] from Bradley J. Katz and his team at the University of Utah in Salt Lake City (USA) to this extent has shown that light of certain wavelengths may adversely affect migraine headaches. 48 patients with chronic migraine – ie. patients who suffer from migraine pain more than half the total days in a month – participated in the study. They were to wear contact lenses for two weeks with one of two different optical filters. One of these filtered out blue light (wavelengths in the range of 480 nanometers), the other filtered out orange-red light (wavelengths in the range around 620 nanometers).

On account of previous study findings [Paywall] the researchers had suspected that blue light in particular enhances the pain of migraine. In actual fact, the subjects felt significantly less impaired by migraine headaches when testing both filters. “Our results show that contact lenses with an optical filter that filters out light of specific wavelengths may be a useful adjunct in the treatment of chronic migraine”, write Katz and his team.

All colours intensify the migraine pain – apart from green

An American-Israeli research team led by Rami Burstein has now discovered [Paywall] a similar relationship: light of various colours may intensify migraine pain – with the exception of green, which apparently attenuates the headache.

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Rami Burstein © Beth Israel Deaconess Medical Center

The team led by Burstein examined for the first time how different coloured lights affect the headache intensity during an acute migraine attack. Their study with 69 migraine patients taking part whose role in the study involved sitting in a dark room during an attack and looking at white, blue, green, orange-yellow and red light of increasing light intensity one by one. Alongside this, the participants gave ongoing information on the strength of their pain. At the same time, the researchers recorded the electrical activity of the subjects’ retinal cells and brain using electrodes: one tiny electrode on the cornea of the eye (electroretinography, ERG) and electrodes on the scalp (electro-encephalogramm, EEG).

Almost all light colours led to an increase in migraine pain: with white, blue, red and orange-yellow light, pain intensity increased by 15 to 19 percent. The colour green was the only exception: here the pain increased at medium light intensity by only about 5 percent. With green at low light intensity, the subjects even reported a decrease in pain: an average of 15 percent, to be exact. This effect was also reflected in the physiological data: the electrical activity of the cells in both the eye and the brain rose considerably less with green light than with any other light colour.

Photosensitivity could originate in the eye

In another experiment Burstein and his team recorded the activity of nerve cells in the thalamus of rats. In this brain region nerve cells that transmit the sense signals from the retina of the eye come together with neurons which play a role in pain. “This interconnection may explain why light can enhance the pain during a migraine attack and why headaches can lead to vision problems”, Burstein explains. The researchers observed that the neurons in the thalamus were most activated by blue light and least by green light – with white light activation being in the middle range.

“Taken together, the results suggest that light sensitivity in migraine might arise in the retina of the eye and is modulated in the nerve cells of the thalamus”, write Burstein and his team. Other current results [Paywall] also show that the light-sensitive ganglion cells in the retina of the eye might play an important role in the development of increased light sensitivity.

Seeing the world through green-coloured glasses

In the future, low intensity green light could possibly be used for therapeutic purposes: It could during a migraine attack help to reduce sensitivity to light and possibly also the headache’s intensity. In addition, special sunglasses or contact lenses could be used which only transmit green light. A similar effect could be had by an environment with subdued green light.

At the moment Burstein and his team are already working on developing inexpensive lamps that emit pure green light at low intensity – and also affordable glasses that filter out all wavelengths up to green. “Until now such lamps and filters have remained prohibitively expensive”, says Burstein.

The results should therefore be reviewed once again in future studies, the researchers say. At the same time an examination should take place to see how green light has effects on different types of migraine – such as those with and without aura – and what effect green light has on healthy folk.

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I’d like to share this article with a friend, but don’t want to be associated in his mind with pictures of pole dancers. Oh well.

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