There is currently a body of research related to Irlen Syndrome, Colored Overlays and Colored Filters that spans nearly 40 years. The Irlen Method and the efficacy of colored overlays and colored lenses have been the subject of over 200 research studies encompassing the disciplines of education, psychology, and medicine. To date, more than 100 of these studies supporting the use of colored overlays and lenses to treat the perceptual processing difficulties associated with Irlen Syndrome are published in peer-reviewed academic and scientific journals, including the Journal of Learning Disabilities, Australian Journal of Special Education, Perceptual and Motor Skills, Australian Journal of Learning Disabilities, Journal of Clinical & Experimental Neuropsychology, Journal of Research in Reading, Behavioral Optometry, and Ophthalmological and Behavioral Optics, among others.
Summary of Research on Irlen Syndrome and Color Intervention
This research has established a hereditary component of the disorder7-9, a number of biochemical markers for problems associated with Irlen Syndrome10-13, and differences in brain function for individuals with Irlen Syndrome14-19, 41. The research has repeatedly documented the efficacy of both colored overlays and spectral filters, as measured by improvements in a variety of reading skills20-32, 42-43, reduction in physical symptoms that include headaches, migraines, eye strain, fatigue, and light sensitivity15, 33-36, and improved functioning and success in both academia and the workplace25-26, 34, 37-39.
Notably, the most current research on Irlen Syndrome and the use of color utilizes advanced brain-mapping technology to show actual changes and normalization of brain functioning that is not achieved through ophthalmological treatments (plain lenses, prisms, or vision therapy). Researchers have utilized functional magnetic resonance imaging (fMRI), visual evoked responses (VER), and single photon emission computed tomography (SPECT) scans to objectively document the profound effects of visual sensory overload on the brain and the normalization of brain activity when individually prescribed, precision-tinted colored filters are worn. An ongoing fMRI study at Cornell University has shown that Irlen Spectral Filters reduce overactivity in both the primary and secondary visual regions as well as fronto-parietal attentional networks. These results suggest that precision-tinted spectral filters reduce uncontrolled cortical excitability to patterned light stimulation as a potential mechanism of action18, 41. When comparing the brains of 42 people with Irlen syndrome to 200 age-matched individuals without any evidence of Irlen syndrome, SPECT scans showed increased activity in the brain’s emotional and visual processing centers and decreased activity in the cerebellum (an area that helps to integrate coordination and new information)40. Functional magnetic resonance imaging (fMRI) was used to investigate activation during sentence reading before and after wearing color-tinted lenses and showed the reading speed of patients improved by more than 20% while wearing the selected lenses21. This is the first study to use brain imaging as a direct correlate to reading performance, showing that changes in brain function with precision-tinted colored lenses correspond directly to positive improvements in reading performance. Yellen and Schweller (2009) utilized state-of-the-art Visual Evoked Responses (VER), a portion of their comprehensive neuroelectrical evaluation of patients called the DESA®, and discovered that individuals with Irlen Syndrome have early hyper-reactivity to visual stimuli somewhere between 30-60 milliseconds, and it is 3-9 standard deviations above normal (the Yellen-Schweller Effect). Irlen Spectral Filters reduce the standard deviation abnormalities of the Yellen-Schweller Effect, lessening of the delay of the brain coming back “online” and allowing it to clear sooner19. Magnetoencephalography (MEG) has been used to characterize visual responses in conditions with and without Irlen Spectral Filters. In all cases, the evoked magnetic signal reflected a complicated pattern of bilateral activation of multiple cortical generators. A major difference in with and without lens conditions was seen between 170 and 200 msec post-stimulus. The data suggest that Irlen Spectral Filters provide for normalization and crystallization of visual information processing in individuals with Irlen Syndrome16. Chouinard et al. (2011) compared the neurological characteristics of a person with Irlen Syndrome with control subjects who were participating in a language task. The descriptive results indicated that there are numerous significant differences in many areas of the brain cortex between the control subjects and the individual with Irlen Syndrome, providing evidence of a neurobiological foundation for Irlen Syndrome14. Huang et al. (2011) used fMRI to investigate differences between individuals suffering visual stress and controls in relation to migraine and to determine the effectiveness of precision-tinted colored filters for individuals suffering from visual stress. The research showed a normalization of cortical activation and spatial frequency tuning in the migraineurs by precision tinted filters, which suggests a neurological basis for the therapeutic effect of these lenses in reducing visual cortical hyperactivation in migraine15.
Independent research projects are ongoing at various universities in the United States, England, Australia, Switzerland, Italy, and New Zealand.
Colored overlays are considered an approved accommodation for standardized tests by many states including California, Massachusetts, New Mexico, Nevada, and Oklahoma.
Incidence of Irlen Syndrome in the Population
Incidence studies suggest that 46% of those identified with reading problems, dyslexia, attention deficit disorder, or learning difficulties suffer from Irlen Syndrome and can be helped by the Irlen Method. Sometimes the Irlen Method is the only solution needed, but more often, the Irlen Syndrome is just one layer of the individual’s problems, and the Irlen Method can be one piece of the solution puzzle. This method does not replace the need for instruction, remediation, or medical intervention.
The Irlen Method in the Education System and Government Support
There are presently over 7,000 educators trained as Irlen screeners, many of whom work within school districts in the United States and overseas. Over 100,000 adults and children wear Irlen Filters and millions of individuals are using Irlen Colored Overlays. Massachusetts and Oregon have bills pending to require screening for Irlen Syndrome in all schools in these states. Alabama has recognized Irlen Syndrome/Scotopic Sensitivity as a learning disability and all recommendations including the use of Colored Filters must be allowed. The Medical Research Council at Cambridge University, Visual Perception Unit of Essex University in England, University Laboratory of Physiology at Oxford University, and Newcastle University in Australia have extensively researched and published studies on colored overlays and Colored Filters.
Brain research at the cellular level has provided new information regarding the operation of the visual pathways in dyslexics as opposed to normal readers and provides a plausible explanation for the demonstrated effectiveness of Irlen Filters and colored overlays. Brain studies conducted at the Amen Clinic and the U.S. Naval Air Warfare Center Weapons Division, show that color helps to balance brain functioning and that the Irlen effect is real.
Agencies Officially Recognizing the Irlen Method
The following are a sampling of agencies that have officially recognized the Irlen Method: Recording for the Blind, SAT, ACT, LSAT, Illinois Department of Rehabilitation Services, Indiana Office of Vocational Rehabilitation, Michigan Vocational Rehabilitation Services, Texas Commission for the Blind, Nevada Vocational Rehabilitation Services, and Wisconsin Vocational Rehabilitation.
In Australia, the following are a sampling of agencies that have officially recognized the Irlen Method: Department of Employment, Education & Training, Departments of Army, Navy and Air Force, Board of Studies-NSW, Board of Secondary Education-WA, Department of Children’s Services-WA, Commonwealth Employment Service (CES), Department of Rehabilitation, and Technical and Further Education (TAFE).
Headaches and Migraine Research and the Irlen Method
Research has just begun to show the connection between headaches and migraines and the Irlen Method. For individuals whose headaches or migraines are caused by light sensitivity, the Irlen Method can make a big difference.
Traumatic Head Injuries
This research highlights two things. First, the use of color to treat light-based sensitivities, physical discomfort, and perceptual difficulties in the environment and on the printed page is not restricted to those who have inherited difficulties. This technique is also effective for those whose difficulties are acquired through TBI.
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