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Published: 19 November 2025

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Hempenstall, K. (2020). Behavioral optometry and Irlen lenses to resolve reading problems. Perspectives on Language and Literacy, 46(1), 17-20.

"Learning to read in the English language is particularly difficult, comprising a mix of several languages that employ different spelling conventions. Yet, reading is very highly valued in modern civilization, and much effort is expended in attempting to discover why an unacceptably high number of students fail to master the skills involved in reading. Although there has been much research on how to teach reading, another direction has involved attempting to determine the processes underlying skilled reading, and then designing interventions to develop those skills directly. One such domain involves visual processes. If a child displays a problem with reading, it sounds at least plausible that vision may be the source of the problem. Indeed, extreme levels of visual disability can preclude conventional reading. But, what about those struggling with reading whose visual problems are adequately corrected with optometric lenses, and those whose reading progress is of concern, but whose vision is considered within the normal range by conventional optometric assessment? Might there be some other vision problems not assessed or detected in this way that cause reading problems?

The history of education is littered with claims of resolving educational problems by directly modifying processes that are presumed to be central to reading, for example, visual perception, balance, primitive reflexes, auditory processing speed, perceptual motor skills, brain patterns, auditory memory, and so on. Some are decidedly distal from the activity of reading, while others have more proximal links. Reading is a complex behaviour, and the idea of intervening at a simple level to produce a complex effect is appealing.

Generally speaking, the direct teaching of underlying processes has not improved reading (Fletcher et al., 2011; Arter \& Jenkins, 1979). In some cases, the interventions didn’t improve the underlying processes. In other cases, the underlying processes improved, but reading skills did not. In still others, there were difficulties in accurately assessing the processes and/or teaching them effectively. Further, weaknesses in these processes were also found among skilled readers. There has been a long search for a holy grail that removes the obstacle to learning such that reading attainment will then occur. If one could be discovered, then time-consuming, explicit instruction in reading would become less necessary for those who currently struggle to learn to read. Unfortunately, the underlying process approach has thus far represented an educational cul-de-sac.

Fuchs, Hale, and Kearns (2011)  reviewed the evidence generally for such cognitively focused aptitude-treatment interactions. They concluded that treating a cognitive deficit in order to enhance a life skill such as reading has no substantial evidential support thus far; however, it is possible that some future cognitively focused interventions will be shown to be valuable. They concluded that an array of strong empirical, independent evidence is necessary, but not as yet available. To provide ineffective interventions has serious negative implications for struggling students. Even if the interventions are otherwise non-harmful, there is an opportunity cost for students (and often a financial cost to parents), and a residue of negative emotion for both parents and child when the approach has no discernible effect.

There are two major areas of interest in judging whether an intervention has merit. The first is to consider whether the theoretical constructs behind the intervention are consistent with what is accepted knowledge about a given educational issue (i.e., face validity). This is not a perfect criterion, as occasionally a new paradigm makes earlier theories obsolete. However, that is relatively rare. In the case of the various approaches that implicate vision problems as the cause of reading problems, one would acknowledge that they sound plausible (to a greater or lesser degree). Indeed, the early history of reading research emphasised a visual-based over the current language-based causation. The second criterion goes beyond the theoretical relevance, and is the issue of whether addressing the reading problem by intervening at the visual level has a positive impact. So, it becomes then an empirical issue, rather than a purely theoretical one.

The reading process requires complex eye movements. Rather than moving smoothly across a line of print, eyes travel in short staccato-like jerks called saccades (covering about eight letter spaces usually), followed by brief fixations (250 ms) during which we gain visual information (Clifton et al., 2016). Its easy to envisage problems occurring for some students in this complex visuo-perceptual coordination task, not to mention the impact of the complexity involved in fluent orthographic processing. Further complicating reading is the fact that humans do not have a dedicated brain module for reading rather (it is) the result of a neuronal recycling from an area of the brain that evolution has dedicated to the recognition of certain forms, notably intersections of straight lines or curves (Quercia, Feiss, \& Michel, 2013, p., 873).

Researchers have noted numerous visual skills in which a proportion of students diagnosed with dyslexia have been shown to be deficient. The list includes: perception of low contrast, low spatial frequency and orientation, high frequency temporal visual information, short visual attention span (Quercia et al., 2013). Vellutino and Fletcher (2005) also described some low-level visual deficits, such as visual tracking, convergence problems, and weakness of the magnocellular system. Such a list of apparent deficits seems legitimate; however, just because they co-occur with dyslexia doesn’t mean they cause dyslexia. Additionally, it is possible that both dyslexia and visual skills deficits are caused by a third variable.

So, the presence of a range of visual problems among struggling readers does not of itself mean that they cause reading problems. Although significant visual differences have been found between dyslexic and normally developing readers, only about 30% of dyslexics are so affected (Ramus et al., 2003). One can find some of these visual processing deficits among skilled readers too, which implies that the visual processing deficit is not the defining characteristic of dyslexia. The identified oculomotor anomalies are considered by the majority of researchers to be secondary to difficulties of cognitive analysis of language (Quercia et al., 2013; Vaughn \& Linan-Thompson, 2003).

     Another finding regarding dyslexic readers eye movements was that their focus frequently shifted back to the left along the text line instead of to the right (i.e., regression). The product of this faulty logic was that a lot of children wasted potential instructional time with eye exercises. However, research has shown that resolving reading problems through effective teaching caused excessive regressive eye movements to cease. Regressive eye movements do not cause reading problems, but are instead a consequence of reading problems.

The two main interventions for dyslexia that emphasise the treatment of visual deficits are behavioral optometry and Irlen lenses. Proponents for each claim that the focus of their interventions directly impacts reading development.

Behavioral Optometry

The criticisms of behavioral optometry treatments for dyslexia are extensive and include, among others, the absence of well-designed studies (Barrett, 2009); failure of studies to produce evidence of visual processing being causal to reading difficulties (Vellutino, Fletcher, Snowling, \& Scanlon, 2004 ); varied definitions of dyslexia and assessment techniques (Schulte-KÃrne \& Bruder, 2010); absence of reliable effects on reading of behavioral optometry interventions (National Health \& Medical Research Council of Australia, 2009; Rawstron, Burley, \& Elder, 2005); and unestablished validity and reliability of tests of accommodation, convergence, and eye tracking (Larson, 2018).

The scientific consensus is that learning to read is either unrelated to magnocellular disturbance (American College of Opthalmologists, 2009 ; Birch \& Chase, 2004; Shelley-Tremblay, Syklawer, \& Ramkissoon, 2011), or is followed by changes in the magnocellular system, and not vice versa (Georgiou, Papadopoulos, Zarouna, \& Parrila, 2012). Furthermore, not all students with dyslexia have these deficits (Ramus et al., 2003), and some typically developing readers apparently do (Creavin, Lingam, Steer, \& Williams, 2015 ; Quercia et al., 2013). For example, in the Creavin et al. study of 5,822 students, 80% of the dyslexia cohort displayed normal ophthalmic results in each of the tests involved. Relevant major national bodies actively discourage the use of behavioral optometry for educational interventions (Handler \& Fierson, 2011; National Health \& Medical Research Council of Australia, 2009; Royal Australian and New Zealand College of Ophthalmologists, 2016 ). Studies reporting that short-term prism correction aided reading likely are manifestations of placebo as the effect appears to be ephemeral (Chung \& Borsting, 2018). In contrast to the lack of evidence for visual intervention, instruction in phonics, word analysis, reading fluency, and comprehension for dyslexia has an acknowledged positive impact (Galuschka, Ise, Krick, \& Schulte-Korne, 2014; Hyatt, Stephenson, \& Carter, 2009; Stein, 2015). The consensus among independent researchers is that vision-based treatment for academic problems, and in particular, dyslexia, does not have the evidence base to support its use. In an evidence-based practice era of education, it would not be in students best interests to use behavioral optometry to address reading difficulties.

Scotopic sensitivity and Irlen lens

Helen Irlen was a psychologist working with adults with reading difficulties during the 1980s. She believed that she had detected a visual stress problem in many of these adults that involved undue sensitivity to particular light frequencies. The frequencies varied among the individuals, and she developed assessment intended to determine which frequencies were problematic for each client. She named the condition scotopic sensitivity syndrome (SSS), and began to prescribe colored lenses, either as eyeglasses or as overlays, to reduce this visual stress. She described a variety of visual sensations reported by clients as: print that ran down the page like a river, blurriness, and words flickering, floating, or sliding off the page (Chouinard, Zhou, Hrybousky, Kim, \& Commine, 2011).

The success or otherwise of the prescribed overlay or glasses was determined by the subjective response of the client as to whether they believed a particular hue was helpful in alleviating their symptoms and enhancing their reading. This approach to evaluation produces its own problems, such as novelty and placebo (Galuschka, Ise, Krick, \& Schulte-Korne, 2014). Additionally, Irlen asserted that a precise color is needed to treat Irlen Syndrome. One would anticipate that the choice of color would be similar if a person was re-assessed. However, Suttle, Barbur, and Conway (2017)  observed that only one-third of candidates chose the same color overlay on re-assessment at 25 days. Further, there was a gender issue reported by Conway, Evans, Evans, and Suttle (2016). More males preferred stereotypical male colour lenses (blue and green), whereas females mainly preferred stereotypical female colours, such as pink and purple. Griffiths, Taylor, Henderson, and Barrett (2016) concluded there was a high false positive rate for Irlen Syndrome using these scales. They also reported a high rate of discontinuation of treatment: 63% had ceased wearing the lenses after three weeks. The internal validity and reliability of the Irlen assessment scales have not been published in any refereed journal.

Scotopic sensitivity and Irlen lenses and overlays were enthusiastically and uncritically endorsed by many lay audiences, including the media. And,  it remains accepted as a valuable treatment for dyslexia by many teachers (Bain, Brown, \& Jordan, 2009; Washburn, Mulcahy, Joshi, \& Binks-Cantrell, 2016). However, the approach has been and remains controversial in the research community, both because it has been argued that no such syndrome exists (American Optometric Association, 2003), and that the treatment has not been demonstrated to be effective in well-designed studies (Griffiths et al., 2016; Iovino, Fletcher, Breitmeyer, \& Foorman, 1998; Ritchie, Sala, \& McIntosh, 2011; Suttle, Lawrenson, \& Conway, 2018). Further compromising the educational relevance of SSS is that scotopic sensitivity has also been reported among typically developing readers (Lopex, Yolton, Kohl, Smith, \& Saxerud, 1994).

Decades of well-designed studies have failed to demonstrate a beneficial impact of this approach to reading. Conversely, the quality of supportive research has been generally inadequate, and numerous studies that reported benefit have methodological weaknesses. For example, effects reported in studies in which there was no active control group disappeared when a placebo control group was employed (Elliot \& Wood, 2017; Galuschka, Ise, Krick, \& Schulte-Korne, 2014). A meta-analysis that  included randomized controlled trials was generally negative (Albon, Adi, \& Hyde, 2008; Suttle, Lawrenson, \& Conway, 2018). In a 2016 systematic review of the literature, Griffiths et al. noted high levels of risk of bias in many studies, and the lower risk studies tended to offer less support for beneficial effects. This led them to conclude that any positive effects are most likely due to placebo, practice, or Hawthorne effects.

As with behavioral optometry, the use of Irlen lenses and overlays is discouraged by the relevant official bodies because of the absence of theoretical salience, contentious assessment tools, poor research design, and an absence of clear empirically supported  student reading outcomes (Handler, Fierson, and the Section on Ophthalmology and Council of Association for Pediatric Ophthalmology and Strabismus, and American Association on Children with Disabilities, American Academy of Ophthalmology, American Certified Orthoptists, 2011; American Academy of Ophthalmology, 2009; National Health \& Medical Research Council of Australia, 2009; Royal Australian and New Zealand College of Ophthalmologists, 2016 ). Nonetheless, Irlen lenses and overlays still continue to be heavily promoted as a worthy treatment for dyslexia, despite insufficient evidence that their use improves the reading skills of low progress readers.

References

Albon, E., Adi, Y., \& Hyde, C. (2008). The effectiveness and cost-effectiveness of coloured filters for reading disability: A systematic review. DPHE Report No.67. Birmingham, UK: West Midlands Health Technology Assessment Collaboration (WMHTAC).

American Academy of Ophthalmology. (2009). Learning Disabilities, Dyslexia, and Vision - A Joint Statement of the American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus and American Academy of Ophthalmology. Retrieved from http://www.aao.org/about/policy/upload/Learning-Disabilities-Dyslexia-Vision-2009.pdf

American Optometric Association. (2003). The use of tinted lenses for the treatment of dyslexia and other related reading and learning disorders. Retrieved from http://web.archive.org/web/20000226214742/http://aoanet.org:80/ia-tinted.html

Arter, J. A., \& Jenkins, J. R. (1979). Differential diagnosis—Prescriptive teaching: A critical appraisal. Review of Educational Research, 49, 517555.

Bain, S. K., Brown, K.S., \& Jordan, K.R. (2009). Teacher candidates' accuracy of beliefs regarding childhood interventions. The Teacher Educator, 44(2), 71-89.

Barrett, B. T. (2009). A critical evaluation of the evidence supporting the practice of behavioural vision therapy. Ophthalmic and Physiological Optics, 29, 4-25.

 Birch, S \& Chase, C.H. (2004). Visual and language processing deficits in compensated and impaired dyslexic college students. Journal of Learning Disabilities, 37, 389 412.

Chouinard, BD, Zhou, Cl, Hrybousky, S, Kim, ES, \& Commine, J. (2011). A functional neuroimaging case study of Meares-Irlen syndrome/visual stress (MISViS). Brain Topography, 25, 293307.

Chung, A.G., \& Borsting, E. (2018). The impact of short-term prism correction in convergence insufficiency on reading rate and accuracy. Optometry \& Visual Performance, 6(1), 11-18.

Clifton, C. E., Ferreira, F., Henderson, J. M., Inhoff, A. W., Liversedge, S., Reichle, E. D., \& Schotter, E. R. (2016). Eye movements in reading and information processing: Keith Rayners 40 year legacy. Journal of Memory and Language, 86, 1-19.

Conway, M.L., Evans, B.J., Evans, J.C. \& Suttle, C.M. (2016). Does gender influence colour choice in the treatment of visual stress? PLoS ONE, 11(9), e0163326.

Elliot, D.B.; \& Wood, J.M. (2017). Coloured filters show gender differences and poor repeatability. Ophthalmic and Physiological Optics, 37, 635-639.

Fletcher, J.M., Stuebing, K.K., Barth, A.E., Denton, C.A., Cirino, P.T., Francis, D.J., \& Vaughn, S. (2011). Cognitive correlates of inadequate response to intervention. School Psychology Review, 40, 3-22.

Galuschka, K., Ise, E., Krick, K., \& Schulte-Korne, G. (2014). Effectiveness of treatment approaches for children and adolescents with reading disabilities: A meta-analysis of randomized controlled trials. PLoS ONE, 9(2): e89900. doi:10.1371/journal.pone.0089900

Georgiou, G.K., Papadopoulos, T.C., Zarouna, E., \& Parrila, R. (2012). Are auditory and visual processing deficits related to developmental dyslexia? Dyslexia, 18, 110-29.

Griffiths, P.G., Taylor, R.H, Henderson, L.M., \& Barrett, B.T. (2016). The effect of coloured overlays and lenses on reading: A systematic review of the literature. Ophthalmic \& Physiological Optics, 36, 519-44. doi: 10.1111/opo.12316.

Handler, S.M., \& Fierson, W.M., American Academy of Pediatrics, \& the Section on Ophthalmology and Council of Association for Pediatric Ophthalmology and Strabismus, and American Association on Children with Disabilities, American Academy of Ophthalmology, American Certified Orthoptists. (2011). Joint Technical Report—Learning disabilities, dyslexia, and vision. Pediatrics, 127, 818-856.

Hyatt, K.J., Stephenson, J., \& Carter, M. (2009). A. review of three controversial educational practices: Perceptual motor programs, sensory integration, and tinted lenses. Education and Treatment of Children, 3, 313-342.

Iovino, I., Fletcher, J.M., Breitmeyer, B.G., \& Foorman, B.R. (1998). Colored overlays for visual perceptual deficits in children with reading disability and attention deficit hyperactivity disorder: Are they differentially effective? Journal of Clinical and Experimental Neuropsychology, 20, 791-806.

Larson, S.A. (2018). Is oculomotor testing important in developmental dyslexia? JAMA Ophthalmology, Published online July 19, 2018. doi:10.1001/jamaophthalmol.2018.2805

Lopex, R., Yolton, R.L., Kohl, P., Smith, D.L., \& Saxerud, M.H. (1994). Comparison of Irlen scotopic sensitivity syndrome test results to academic and visual performance data. Journal of American Optometric Association, 65, 70514.

Mann, L. (1979). On the trail of process. New York: Grune \& Stratton .

National Health \& Medical Research Council of Australia. (2009). Alternative Therapies for ADHD. Retrieved from http://www.mental-health-matters.com/disorders/mood-disorders/bipolar/941-altervative-therapies-for-adhd?tmpl=component\&type=raw\&showall=1

Quercia, P., Feiss, L., \& Michel, C. (2013). Developmental dyslexia and vision. Clinical Ophthalmology, 7, 869-881.

Ramus, F., Rosen, S., Dakin, S. C., Day, B. L., Castellote, J. M., White, S., \& Frith, U. (2003). Theories of developmental dyslexia: Insights from a multiple case study of dyslexic adults. Brain, 126, 841-865.

Rawstron, J.A., Burley, C.D., \& Elder, M.J. (2005). A systematic review of the applicability and efficacy of eye exercises. Journal of Pediatrics, Ophthalmology, and Strabismus, 42, 82-88.

Ritchie, S.J., Sala, S.D., \& McIntosh, R.D. (2011). Irlen colored overlays do not alleviate reading difficulties. Pediatrics, 128, 932-938.

Schulte-KÃrne, G., \& Bruder, J. (2010). Clinical neurophysiology of visual and auditory processing in dyslexia: A review. Clinical Neurophysiology, 121, 1794-1809.

Shelley-Tremblay, J.F., Syklawer, S., Ramkissoon, I. (2011). The effects of magno-parvocellular integration training on fluency Journal of Behavioral Optometry; 22, 31-37.

Stein, M.T. (2015). Visual training methods are ineffective for dyslexia. New England Journal of Medicine: Journal Watch, June 2, 2015. Retrieved from http://www.jwatch.org/na38060/2015/06/02/visual-training-methods-are-ineffective-dyslexia

Suttle, C.M., Lawrenson, J.G., \& Conway, M.L. (2018). Efficacy of coloured overlays and lenses for treating reading difficulty: An overview of systematic reviews. Clinical and Experimental Optometry, 101, 514-520. https://doi.org/10.1111/cxo.12676

Vaughn, S., \& Linan-Thompson, S. (2003). What is special about special education for students with learning disabilities? Journal of Special Education, 37, 140-147.

Vellutino, F.R., \& Fletcher, J.M. (2005). Developmental dyslexia. In Margaret J. Snowling and Charles Hulme (Eds). The science of reading: A handbook. Maldon, MA: Blackwell Publishing, pp. 362-378.

Washburn, E.K., Mulcahy, C.A., Joshi, M.R., \& Binks-Cantrell, E. (2016). Teacher knowledge of dyslexia. Perspectives on Language and Literacy, 42, 9-13.

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Now for some more recent papers on these topics

The Lived Experience of Parents of Children with Irlen Syndrome: A Biopsychosocial Perspective of the Effects of Tinted Lenses and Colored Overlay (2021)

"Reading illiteracy is a continuing problem in society. Irlen purported many individuals struggle with reading due to a perceptual processing problem called Irlen Syndrome (IS).

Existing research supports the use of colored overlays and tinted lenses to alleviate reading difficulties but has focused primarily on the biological benefits of improved

reading while neglecting the IS childs psychological and social well-being. Viewed from a biopsychosocial perspective, the purpose of this qualitative phenomenological study

was to explore the lived experiences of parents of children with IS who used colored overlays or tinted lenses. Engels biopsychosocial theory acted as a guide for the interpretation of themes that emerged from the data analysis. Data were collected using a nonprobability purposeful sample strategy.

This studys sample consisted of 11 parents with IS children who used colored overlays or tinted lenses for 4 months or longer. Parent interview transcripts were analyzed using hand coding and NVivo computer software. It was found that parents of IS children reported improvements in their childs overall

reading, writing, homework completion, self-confidence, sociability, emotional regulation, and physical well-being when using colored overlays and tinted lenses.

Findings revealed that many parents struggled with school personnels ability to understand and accept IS as a diagnosis and provide their child with consistent adaptive

device accommodations. The results of this study may lead to positive social change by giving practitioners and educators a greater understanding of IS and its biological, psychological, and social processes."

Young, B. L. (2021). The Lived Experience of Parents of Children with Irlen Syndrome: A Biopsychosocial Perspective of the Effects of Tinted Lenses and Colored Overlays (Doctoral dissertation, Walden University).

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Abstract expressionist painting of a happy crowd of people wearing sunglasses. What is Irlen Syndrome? (2022)

“Irlen Syndrome has been described as a perceptual processing issue that impacts the way the brain processes visual information (Miyasaka, Vieira, Novalo-Goto, Montagna, \& Wajnsztejn, 2019). Irlen Syndrome is said to manifest in various visual alterations, including sensitivity to brightness, poor adaptation to colour contrasts (light and dark), moving or blurring letters while reading, cloudiness around the edges of ones vision, difficulty holding ones eyes on a target, and changes in depth perception. Some of the listed symptoms of Irlen Syndrome include poor reading ability, headaches or migraines, problems with depth perception, light sensitivity, eyestrain and fatigue, and problems with attention and concentration. The exact cause of Irlen syndrome is unknown, however some hypothesize that it is associated with deficits in the magnocellular system, or that it possibly has a genetic component.

However, controversy surrounds the diagnosis of Irlen Syndrome. There is disagreement on whether Irlen Syndrome actually exists, and if it does exist; does it exist as a distinct diagnostic entity, or are the symptoms better explained as part of another disorder?

This following position is held by The Royal Australian and New Zealand College of Ophthalmologists (RANZCO). They released a statement in 2018 stating that there is no good quality evidence that Irlen Syndrome exists, stating that:

“Despite Irlen Syndrome being first described in the early 1980s, there is still no sound theoretical basis or evidence that the condition actually exists. A diagnosis of Irlen Syndrome is based solely on symptoms with no quantitative physiological correlation.”

Furthermore, Irlen Syndrome is also not recognised by the majority of the medical community, including the World Health Organisation, the American Academy of Ophthalmology, the American Academy of Pediatrics, the American Association for Pediatric Ophthalmology and Strabismus, and the American Association of Certified Orthoptists.

Irlen lenses

The controversy also extends to the only known treatment of Irlen Syndrome, known as Irlen lenses. Irlen lenses are specially tinted lenses or filters that supposedly reduce the visual distortions and other symptoms associated with the syndrome. This is proposed to work by reducing the contrast between light and dark, making for easier retinal photoreceptor adaptation. This should theoretically improve reading comprehension, reduce fatigue, give a better sensation of depth, and help with attention.

A systematic review of 44 articles on Irlen Syndrome published between 1989 and 2018 showed mixed results, with many studies showing strong selection bias in participant recruitment and dubious instrument validity and study design (Miyasaka et al., 2019). Fourteen of the studies found weak evidence supportive of filtered lenses, 14 of the studies did not find evidence that filtered lenses were effective, five studies were inclusive, and four studies suggested more studies needed to be carried out before any conclusions could be drawn. 

The authors of the systematic review concluded that despite the 30 years of mixed-quality evidence, they cannot say definitively that Irlen Syndrome and its symptoms do not exist, but that the screening and diagnostic tests are of questionable quality. Furthermore, they stated that the prescription of coloured lenses as a treatment should not be recommended due to poor quality evidence, and that any benefits ascribed to this treatment method are likely due to a placebo effect, or due to a practice effect with regards to reading improvements. 

The Royal Australia and NZ College of Opthalmologist have made a strong statement on the use of Irlen lenses. Overwhelmingly the research shows no benefit from this treatment in children with reading difficulties and vulnerable parents are being exploited and having their children subjected to unnecessary screening practices.

Putting aside the controversy around Irlen Syndrome, it is claimed by Irlen organisations that autistic children have higher rates of IS than the neurotypical population.

Is Irlen Syndrome more common for autistic children?

Estimates from Irlen organisations speculate that a high number of autistic children also have Irlen Syndrome and that this pairing is more common than for the neurotypical population, however the sources for these claims are often not cited. When researching this topic, I performed a search for peer-reviewed journal articles on Irlen Syndrome and autism and could not find prevalence rates based on studies with large sample sizes.

When performing a regular Google search on this topic, the first result that pops up is a guest article from the National Autistic Society, a UK-based website. The article was guest written by Tina Yates (2017), an Irlen diagnostician, who says Irlen Syndrome affects well over half of autistic people despite not citing a source for this number.

The Irlen Institution website, founded by Helen Irlen herself, makes no mention of the co-occurring Irlen Syndrome and Autism prevalence rates, and their page on Autism only provides links to two articles from 1990s. For something that supposedly affects over half of autistic people, it is concerning that they have no research from the past 20 years to cite in support of this.

Final thoughts

The symptoms of Irlen Syndrome seem to resonate with a lot of autistic people, however Irlen Syndrome as a diagnosis, the way in which it is diagnosed, and the proposed patented treatment, along with the general lack of quality evidence or support by major medical bodies is a cause of concern.

Beyond the above-mentioned diagnostic and treatment issues, it appears that the only people who are qualified to make this diagnosis are people trained by the Irlen Institute. Coincidentally, they are also the only providers of the specially tinted glasses, and they go to great lengths to state that other tinted glasses will not work; they MUST be Irlen lenses. It was difficult to find an exact cost for all of this as most places in Aotearoa that offer Irlen testing do not list their prices upfront, but an Australian news article estimated the cost for visiting an Irlen diagnostician for a screening and leaving with a pair of lenses could cost around $700, without even accounting for the additional costs of follow up tests (Stevens, 2019). 

Overall, while there may be some overlap between the symptoms of autism and Irlen Syndrome, the evidence for a strong relationship between the two conditions is limited and controversial, as is the legitimacy of the diagnosis and the treatment. There do not appear to be any risks to seeking a diagnosis or trying Irlen lenses if you are experiencing visual symptoms (beyond potentially losing time and money), but as it currently stands, this does not appear to be the best evidence-based practice."

Bettina Lenise Young. (2021). A Biopsychosocial Perspective of the Effects of Tinted Lenses and Colored Overlays. Walden University. https://scholarworks.waldenu.edu/dissertations

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Reading through the eyes of a university student: A double-masked randomised placebo-controlled cross-over protocol investigating coloured spectacle lens efficacy in adults with visual stress. (2025)

"Recent position statements from the College of Optometrists UK \[25] and the Association of Optometrists UK \[27] suggest weaknesses in the current evidence surrounding the effectiveness of coloured lenses, and that the treatment of visual stress with coloured lenses remains controversial. Yet, over 300 optometry practices through out the United Kingdom have an Intuitive Colorimeter and assess patients with reading difficulties and symptoms of visual stress \[68] and the wearing of coloured lenses is not uncommon. In addition, optometric practices may offer alternative methods of visual stress assessment, such as coloured overlay assessment, and ChromaGen contact lens fitting, amongst others. Whilst this study will not directly influence the management of visual stress with these alternative treatments, further knowledge on coloured filter efficacy will be uncovered from the results of this trial. The results of this study will provide the much needed evidence-base for optometrists, orthoptists and other practitioners assessing visual stress and reading difficulties."

Harkin, D. L., Little, J. A., \& McCullough, S. J. (2025). Reading through the eyes of a university student: A double-masked randomised placebo-controlled cross-over protocol investigating coloured spectacle lens efficacy in adults with visual stress. PLoS One, 20(6), e0309625.

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