One of the symptoms of a migraine is an aura. This entails changes in vision that precede a migraine attack. Like many medical conditions, research is taking place to learn more about the condition and possible treatments. Also, there are products that can offer relief from light sensitivity that accompanies a migraine.
Response to Visual Stimulation
Work done at the University of Connecticut (UConn) College of Agriculture, Health and Natural Resources, find that the brains of people who have migraines can’t adjust to visual stimulation in the same way as people who don’t experience this condition.
Daniele Piscitelli, assistant professor of kinesiology at UConn, designed the study and did the data analysis. Colleagues in the laboratory of Kátia Monte-Silva, Ph.D., at the Laboratório de Neurociência Aplicada, Universidade Federal de Pernambuco, Recife, Brazil, did the research work.
There were three groups involved in the study who in the course of 30 days experienced migraines, experienced other kinds of headaches, or didn’t experience migraines or other kinds of headaches. Scientists took measurements of cortical excitability, in each group. Cortical excitability is a measure of how much a person’s brain responds to stimuli. Prior research showed that people who have migraines have higher cortical excitability, which means their brains have a lower tolerance for excitability than healthy populations.
Researchers were interested in two areas of the cerebral cortex:
The visual cortex, which processes visual information
The motor cortex, which controls voluntary movement
They wanted to see what went on in these cortices one day before and one day after a migraine or headache attack.
To assess motor cortex excitability, scientists applied single-pulse transcranial magnetic stimulation (TMS) over the motor cortex and recorded the muscle activity using electromyography (EMG) from the hand muscles. To measure excitability in the visual cortex, researchers asked participants when they saw a light in their field of vision when the TMS was applied over the occipital cortex. In preliminary measurements, there were significant differences between the three groups.
The next part of the study involved subjects looking at a black and white checkerboard that changed colors with one eye covered at a time, known as pattern reversal visual stimulation. Scientists then took the same visual and motor cortex excitability measurements after this stimulation.
It was after the pattern reversal visual stimulation that researchers saw considerable differences between the groups. Those who experienced migraines and other headaches had increased levels of visual cortex excitability compared to the control group. There was no difference in motor cortex excitability. This shows that migraines and other headaches share a neurological basis. It also shows that current medications that reduce visual cortex excitability, such as those to treat epileptic seizures, could be used for migraine and headache sufferers.
The next step in this research will be to conduct a study with people who have seizures to see if they have similar cortical patterns.
“How the brain organizes information is the key to pathophysiology and is probably the key to treat the patients,” Piscitelli says.
Light Sensitivity Lenses
There are lenses for myopia, presbyopia and now you can and lenses to relieve the light sensitivity that comes with migraines, in order to reduce the number of migraines. One such company that offers lenses to relieve light sensitivity is Avulux. Their lenses filter close to 97 percent of blue, amber and red light at the wavelengths that have been shown in various studies to trigger or increase migraine pain.
A study done in 2010 Harvard Medical School demonstrated that other intrinsically-photosensitive retinal ganglion cells or ipRGCs can release melanopsin when exposed to certain wavelengths of light in the 400nm to 500nm range. This study also found that migraines aggravated by light usually involve the photactivation of ipRGCs, which lead activation of melanopsin.
Avulux utilized information from this study and a study done in 2016 at the University of Utah to develop lenses that relieve migraine-induced light sensitivity. This study looked at the effects of wearing glasses that blocked the 480nm wavelength of light against lenses that blocked the 620nm wavelength of light. What they found was that wavelengths of 481nm and 587nm are the peak wavelengths that affect melanopsin.
Avulux lenses are able to filter blue, amber and red light without distorting color perception and they allow green light to enter the eye, which has been shown relieve migraine symptoms. Another great thing about these lenses is that they can be worn indoors and outdoors.
Ray Corbin-Simon, OD, of Piscataway, New Jersey, has prescribed these lenses to patients who don’t have migraines but do complain of light sensitivity and she has found that they help reduce the sensitivity and help them function better. “The increase in technology usage has made our bodies less adaptable,” she said. “We have to find ways to alleviate the symptoms, basically.”
Migraines aren’t pleasant. Just ask someone who gets them. Research has uncovered what is happening in the brain during a migraine and that information can be used to develop treatments. While research is going on, there is relief in the form of color filtering lenses. No longer do migraine sufferers have to learn to “live with it”. They can get relief and get on with their lives.