Prevention of visual stress and migraine with precision spectral filters

Abstract

Individuals who suffer migraine, particularly migraine with visual aura (MwA), are susceptible to physiologically strong visual stimuli and find them aversive. Strong stimuli including bright light and certain visual patterns produce discomfort and perceptual illusions and can trigger migraine attacks. Perceptual illusions and visual discomfort are reported by most migraine sufferers and those with frequent headaches. These phenomena suggest that visual stimulation and consequent visual cortical activity contribute to the triggering of some migraine attacks. Perceptual illusions in MwA patients were found to be associated with hyper-activation in visual cortex. This excessive cortical activity is called visual stress. The cortex is generally hypothesized to be hyperexcitable in migraine, and this hyperexcitability could be the underlying mechanism of visual stress. It is hypothesized that visual stress results from too great a neural (hyperneural) activity in response to strong physiological sensory stimulation, particularly, but not exclusively, visual. A strong physiological visual input may cause a spread of excitation through hyperexcitable cortex, leading to neurons firing inappropriately and thereby resulting in perceptual illusions and distortions, and possibly promoting a migraine attack. Over the last 10 years, the use of colored filters to treat perceptual distortion of text has become common in many schools in Britain. The efficacy of precision spectral filters (PSF) in preventing migraine headache has been reported in several studies. One preliminary study revealed the suppressing effect of the PSF on visual cortical activity in a MwA patient, suggesting that it might be this reduction in cortical activation that is responsible for the reduction of the frequency of migraine attacks in those who benefited from the PSF. PSF offer a possible new prophylactic therapy for migraine. They are safe, free of side effects, and inexpensive. Drug Dev Res 68:469–475, 2007. © 2008 Wiley-Liss, Inc.