Green light for radical migraine treatment
AdAIly dose of green light is being tested in the U.S. as a new way to tackle migraines. While bright light typically worsens the pounding headaches that blight the lives of up to 25 per cent of British women and 10 per cent of men, green light may, intriguingly, have the opposite effect.
Classed among the most disabling conditions by the World Health Organisation, migraines can take three days to pass and cause 25 million work and school days to be lost in the UK each year.
The most common symptom, a throbbing pain on one side of the head, can be accompanied by nausea and sickness, increased sensitivity to light or noise, sweating, stomach pain and diarrhoea.
The exact cause of migraines isn’t known, but they are thought to be due to changes in chemicals, nerves and blood vessels in the brain. Genes may play a role, and some migraines are associated with triggers, from flashing lights and stress to foods or drinks (although food triggers are quite rare).
Painkillers and drugs called triptans can help reverse chemical changes in the brain. And antiemetics are also used to relieve nausea. Now, researchers are studying whether green light could provide a drug-free option.
In 2016, researchers at Harvard University in the U.S. exposed patients to different coloured lights. With bright light usually worsening migraines, leading to sufferers seeking the solace of a darkened room, it wasn’t surprising the blue, amber and red lights all intensified the headaches.
Green light, however, reduced the pain by 20 per cent. Further experiments revealed green light generates smaller signals in the retina, the layer of lightsensitive cells at the back of the eye, than other colours.
Cells in the thalamus, an area of the brain that processes information from the eye, also react less to green light.
The thalamus plays a key role as a processing centre in pain conditions, including migraine.
The finding led to the development of a battery-powered lamp that emits the lowintensity pure green light found to be most effective. Now, in a new trial at Vedanta Research in North Carolina, 250 migraine patients will use the lamp for at least 30 minutes a day for six weeks, while noting how many headaches they have and their severity.
Scientists hope the study will show if the light works to reduce symptoms during an attack and, if used regularly, to lower the risk of an attack.
dr Nick Silver, a consultant neurologist at the Walton Centre NHS Foundation Trust in liverpool, said: ‘This is an extremely exciting time for patients with migraines.
‘An increasing variety of options can treat or prevent attacks, from tablets and injections to handheld nervestimulators. It gives patients more choice and more options to find what works for them.
‘This work related to greenlight treatment may add to the armoury of treatments we have and offer help with few or no side-effects.’