Responding to the 2018 Royal Australian and New Zealand College of Ophthalmologists (RANZCO) Position Statement on Irlen
*This response has been updated from its original publication in 2018 to include additional available research.
In their 2018 released position statement, The Royal Australian and New Zealand College of Ophthalmology (RANZCO), expressed the opinion “There is no scientific evidence that Irlen syndrome exists or that treatment of reading difficulties with Irlen lenses work.” The available body of current neuroscience, biochemical, educational and psychological research appears to have been overlooked by these authors, and as such, we’d like to respond by providing the most current information. We address each of the statements made in the RANZCO position paper one-by-one, systematically providing evidence to refute each statement. This response was originally published in 2018 when the RANZCO paper was first distributed and included a comprehensive list of references available at that time. As research on Irlen Syndrome continues to be published, we have updated the original response to include research published as of today’s date (March 3, 2025).
RANZCO STATEMENT 1. Lack of scientific evidence that Irlen Syndrome Exists.
Neuroscience and biochemical research have both established the existence of Irlen Syndrome, but this research was not reviewed by RANZCO. The RANZCO statement did not include neuroscience research in its literature review. This research utilizes advanced brain imaging technology (fMRI, VEP, MEG) to show abnormal brain function in the visual cortex and surrounding brain areas that corresponds to reported physical and perceptual symptoms for those identified with Irlen Syndrome. This brain imaging research, which shows normalized brain function with colored filters, has also confirmed improvements in reading performance, physical symptoms, such as migraines, and visual distortions1-8. Biochemical studies have also substantiated the existence of Irlen Syndrome9-12.
As a result of ongoing research being conducted at the Human Neuroscience Institute at Cornell University in the United States, Dr. Adam Anderson explained, “Our preliminary fMRI examinations of individuals with Irlen Syndrome, with and without prescribed Irlen color filters, revealed quite dramatic effects on the visual system as well as higher brain structures involved in learning. Consistent with a reduction in visual stress, the filters reduced the overactivity of the visual system during visual stimulation and word reading.” Specifically, Precision-tinted spectral versus blank filters reduced within primary and secondary visual regions as well as fronto-parietal attentional networks, consistent with reduced hyperactivity to visual stimulation and reduced recruitment of neural networks outside of the visual system proper.13
RANZCO STATEMENT 2. Lack of evidence that treatment for Irlen Syndrome is effective.
More than 200 articles published in peer-reviewed scientific journals support the use of color to address symptoms of Irlen Syndrome. Irlen Syndrome is a problem with the brain, not the eye. It is a perceptual processing disorder, not a visual problem. As such, Irlen Syndrome, as with other perceptual processing difficulties, falls under the educational domain and is not considered a medical condition. In addition to causing a variety of physical, cognitive, emotional, and neurological symptoms, one way the condition can manifest is on the printed page. Irlen Syndrome, which is usually inherited, can make reading and other academic tasks more difficult.
Research or Irlen Syndrome and reading performance has a 40-year history, with numerous positive reading-related research studies published in Australian journals14-21. However, in recent years, most researchers have moved beyond reading as a topic of study, recognizing Irlen syndrome as having a much broader impact on daily function and physical well-being, including research in the areas of traumatic brain injury, migraine, social cognition, emotions, facial recognition, and attention. Even with that being said, the most recently released research on the impact of Irlen Filters and reading revealed positive results4, 22-26.
Since 2006, there have been seventeen studies published on the use of colored lenses and reading. Fourteen of these studies had positive results (faster reading rate, improved comfort, enhanced comprehension, reduced visual noise, and increased accuracy)1, 4, 27-39. The other three had inconclusive findings. One inconclusive study used a different method of color selection, not the Irlen Method, and not Irlen Spectral Filters40. The other two studies utilized the same sample of subjects, and both studies have been criticized by experts for using sample sizes that were too small to detect the actual positive changes that appeared in the raw data41-42.
RANZCO STATEMENT 3. Issues with lens choice.
Other available colored lens interventions rely on self-selection of color, but the Irlen Method does not. The Irlen Method uses indicators of performance on a series of diagnostic tasks along with behavioral observation to determine the proper color. It is this unique diagnostic method that makes the Irlen Method different from other colored lens interventions. The color is customized for each individual’s brain so that it filters only the wavelength(s) of light the person’s brain cannot process accurately. Each person ends up with their own unique color to wear25.
RANZCO STATEMENT 4. Poor repeatability of colour choices.
RANZCO’s statement about poor repeatability of color choices is out of line, as none of the studies referenced on this topic utilized the Irlen Method of color selection43. The methods employed by the articles referenced relied on self-selection of color, and were not carried out by a professional trained in the Irlen Method.
RANZCO STATEMENT 5. Placebo effect.
Both longitudinal and placebo-controlled studies have shown improvements in reading and other Irlen-related physical and perceptual symptoms24, 44-47, yet these studies, published in educational and psychological journals, were not considered by RANZCO when making their statement.
In Conclusion
We would like to invite eye care professionals to move beyond the eye and remember the role the brain plays in Irlen Syndrome. To ignore published research in the areas of neuroscience, education, and psychology that takes into account the broader impact of Irlen Syndrome as a neurodevelopmental disorder seems to do a disservice to both the general public that suffers from this condition and the professionals who might be able to help.
References
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