In 2007 a research paper published in the Journal of Neurology found that “Spectral filters can improve reading and visual search in patients with multiple sclerosis.”  the following are excerpts from that paper:
Cortical hyperexcitability has been reported in patients with various neurological conditions and is consistent with three observations in patients with multiple sclerosis; Moreau et al. demonstrated that 17/402 (4%) of their patients with multiple sclerosis experienced at least one epileptic seizure; Gee et al. demonstrated that 56% of their 169 patients with multiple sclerosis who returned a completed questionnaire had reportedly experienced migraines; and, patients with multiple sclerosis may reveal hyperexcitability of the motor cortex.
Patients with multiple sclerosis have also reported experiencing migraines, epileptic seizures, visual discomfort, perceptual distortions, and cortical hyperexcitability. Since spectral filters have been shown to reduce these symptoms in individuals with other neurological conditions (photosensitive epilepsy, migraine, autism and dyslexia), the team investigated the possible benefit of using Intuitive Overlays (spectral filters) to reduce symptoms.
Overlays in 10 colours were offered to be paced over the page during reading and visual search. The team found that when patients were allowed to select an overlay colour that reduced perceptual distortions, almost all of the participants reported fewer perceptual distortions, and 50% read more quickly and omitted fewer targets during visual search.