Irlen syndrome

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Irlen syndrome
Pseudomedical diagnosis

Irlen syndrome, occasionally referred to as scotopic sensitivity syndrome (SSS) or Meares–Irlen syndrome,[1] is a postulated disorder of vision or image-processing in the brain. Irlen syndrome is also sometimes referred to as asfedia or visual stress.[citation needed] Many mainstream professionals are skeptical of the concept.[2][3] Research on Irlen syndrome has produced mixed results, finding a possible neurological basis for the condition[4] but little or no evidence supporting the most commonly proposed treatment using tinted eyeglasses or overlays to aid reading.[5]


In 1980, New Zealand teacher Olive Meares described the visual distortions some individuals reported when reading from white paper. In 1983, American psychologist Helen Irlen wrote a paper about the use of coloured overlays aiding the reading abilities of some people. Similar symptoms were separately described by Meares and Irlen; each unaware of the other's work. Irlen, who was the first to systematically define the condition, named her findings "scotopic sensitivity", though in the discussions and debates over the following years, some referred to it as Meares-Irlen syndrome. The Irlen Institute, founded by Helen Irlen, describes scotopic sensitivity as "a perceptual processing disorder" related to brain interpretations of colours and light.[6]

It remains controversial whether non-Irlen-certified Meares-Irlen syndrome and the original Irlen syndrome are the same condition. Irlen syndrome, for example, seems to include a broader array of symptoms, including severe variants of the core condition. Basic testing for scotopic sensitivity was tried by optometrists, opticians and orthoptists in UK hospitals, and by optometrists and opticians in private practice employing a technique that used the Intuitive Colorimeter, developed under Medical Research Council licence. An alternative approach to correct Irlen syndrome was tried by Orthoscopics franchise in the UK, with wide colour coverage and tints manufactured by Hoyato match. Other commercial organisations have produced sets of therapeutic tints, although most have not received scientific evaluation.[7]

Studies investigating Irlens' syndrome as a treatable condition have been criticised for having a biased and subjective approach to their research.[8]

Treatments offered by Irlens' practitioners have not been found to be effective in improving reading ability.[9]


Irlen divides Irlen syndromes into six types: photophobia, distortion of the fundus, graphical distortions during reading, decreased visual field, difficulty in ocular fixation during reading and change in depth perception.[10]


The disorders have been studied in several institutions, including the Psychology Department at Essex University, the former Applied Psychology Unit, Cambridge University in England, and in the case of Meares-Irlen syndrome, Visual Unit at Glasgow Caledonian University in Scotland. As of 2012 the Visual Stress Unit offered non-commercial diagnostic and therapeutic services to individuals, and provided advice to the Scottish National Health Service.

In Australia, Irlen syndrome was researched by Paul Whiting at the University of Sydney. Whiting set up the first Irlen Dyslexia Centre in Australia, which operated in the Children's Centre at Sydney University for more than 15 years.[11] Irlen syndrome was also studied in Australia by Greg Robinson (1944–2008) at the University of Newcastle. He was director of the Special Education Centre at the School of Education.[12]

In the US, peer-reviewed literature on the topic suggests that much is unknown about the cause of these disorders, ranging from the 2011 study in a journal of the American Academy of Pediatrics, "Irlen Colored Overlays Do not Alleviate Reading Difficulties"[5] and the 2012 study in the journal Brain Topography, "A Functional Neuroimaging Case Study of Meares–Irlen Syndrome".[4] The first, purely in relation to Meares-Irlen syndrome, finds that there is no evidence for one of the fundamental claims of therapeutic benefit. The second, which focused primarily on Irlen syndrome, found compelling evidence of unique brain function linked to the syndrome.


The College of Optometrists (UK) has specified guidelines for optometrists who use the colorimeter system. A society for coloured lens prescribers has been established to provide a list of eye-care practitioners with expertise in the provision of coloured lenses for the treatment of visual stress.[13]

Irlen Method[edit]

The Irlen Method uses coloured overlays and tinted lenses in the form of glass or contact lenses. The method is intended to reduce or eliminate perceptual processing errors; it is claimed the resultant retiming of visual signals in the brain improves the reading difficulties associated with scotopic sensitivity syndrome.[14]

Scientific repudiation[edit]

Skepticism relating to scotopic sensitivity syndrome's exact pathology has evolved on several fronts:

  1. Whether it exists as a distinct, predictably identifiable disease with a reasonable pathophysiological mechanism, or whether a range of symptoms from other conditions are being placed under this convenient heading;
  2. Whether it is causally or incidentally related to dyslexia, autism, or other conditions; and
  3. Whether existing methods of scotopic sensitivity syndrome treatment are appropriate and effective.

A 2009 report by the American Academy of Pediatrics (AAP) does not find that there is conclusive scientific evidence for the use of coloured lenses (one treatment used to relieve symptoms of scotopic sensitivity syndrome) although it acknowledges anecdotal evidence in support of customized colored lenses.[15] When discussing its scientific basis, the AAP mentions that "[t]he method used to select the lens or filter color has been highly variable, the color selection has also shown considerable variability, and the test-retest consistency has been poor" (p. 843).

The association of scotopic sensitivity syndrome and dyslexia has been challenged by many authors in the optometric and ophthalmologic communities.[2] Furthermore, many special education departments at universities challenge the validity of coloured lenses as an effective treatment for the condition as outlined by the Macquarie University Special Education Centre.[16]

In a joint statement, The American Academy of Ophthalmology, American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus and American Association of Certified Orthoptists firmly repudiated the use of lenses, stating that there was no scientific evidence supporting their use. The expense of such treatment is unwarranted and may divert resources from evidence-based treatment.

Critics claim that the symptoms of those with Scotopic Sensitivity Syndrome are related to already known visual perceptual and neurological disorders.[17] According to a statement released by the American Optometric Association in 2004:[18]

There is evidence that the underlying symptoms associated with specifically Meares Irlen Syndrome, are related to identifiable vision anomalies, e.g., accommodative, binocular, and ocular motor dysfunctions, in many patients seeking help from coloured lenses. Furthermore, such conditions return to normal function when appropriately treated with lenses, prisms, or vision therapy. When patients exhibiting Meares Irlen Syndrome were treated with vision therapy, their symptoms were relieved. These patients were no longer classified as exhibiting this syndrome, and therefore did not demonstrate a need for the coloured overlays or tinted lenses.

As outlined by Hyatt, Stephenson and Carter (2009):[19]

In 1990, the Journal of Learning Disabilities published a special issue that provided intensive coverage of Irlen lenses. In the preface to the issue, the editor in chief, Wiederholt, noted that each of the studies had serious theoretical, medical/physical, and methodological flaws, but were published along with articles critiquing the studies to provide readers with an overview of the Irlen procedures as well as guidance for conducting quality research studies. He, along with Hoyt (1990),[20] Parker (1990),[21] and Solan (1990),[22] noted that these initial studies by Blaskey et al. (1990),[23] O'Connor, Sofo, Kendall, and Olsen (1990),[24] and Robinson and Conway (1990)[25] failed to support the treatment validity of colored overlays.


Critics maintain that the term "scotopic sensitivity" is a misnomer given that the symptoms of "scotopic sensitivity syndrome" reportedly occur during photopic conditions. The term "scotopic sensitivity" seems dubious, given that scotopic vision is the vision of the eye under low light conditions and as such vision is provided by rod cells on the retina, which have little if any role in colour vision; it does not make sense that a coloured lens or coloured overlay would have any impact upon "scotopic sensitivity syndrome".


  1. ^ "Irlen Syndrome vs. Visual Stress: Simple Semantics or Something More".
  2. ^ a b Cotton M, Evans K (1990). "A review of the use of Irlen (tinted) lenses". Australian and New Zealand Journal of Ophthalmology. 18 (3): 307–12. doi:10.1111/j.1442-9071.1990.tb00625.x. PMID 2261178.
  3. ^ Miyasaka, Jordan Da Silva; Vieira, Raphael V. Gonzaga; Novalo-Goto, Elaine Shizue; Montagna, Erik; Wajnsztejn, Rubens (March 2019). "Irlen syndrome: systematic review and level of evidence analysis". Arquivos de Neuro-Psiquiatria. 77 (3): 194–207. doi:10.1590/0004-282X20190014. PMID 30970133. S2CID 108293945.
  4. ^ a b Chouinard BD, Zhou CI, Hrybouski S, Kim ES, Cummine J (July 2012). "A functional neuroimaging case study of Meares-Irlen syndrome/visual stress (MISViS)". Brain Topogr. 25 (3): 293–307. doi:10.1007/s10548-011-0212-z. PMID 22124535. S2CID 13065620.
  5. ^ a b Ritchie SJ, Della Sala S, McIntosh RD (October 2011). "Irlen colored overlays do not alleviate reading difficulties". Pediatrics. 128 (4): e932–8. doi:10.1542/peds.2011-0314. PMID 21930551. S2CID 27034274.
  6. ^ What is Irlen Syndrome? The Irlen Institute, accessed 2020-10-08
  7. ^ American Academy Of Pediatrics, Section on Ophthalmology; American Academy of Ophthalmology; American Association for Pediatric Ophthalmology Strabismus; American Association of Certified Orthoptists (August 2009). "Joint statement—Learning disabilities, dyslexia, and vision" (PDF). Pediatrics. 124 (2): 837–44. doi:10.1542/peds.2009-1445. PMID 19651597. S2CID 15631430.
  8. ^ "Irlen Syndrome | Science-Based Medicine". 7 August 2013.
  9. ^ Ritchie, S. J.; Della Sala, S.; McIntosh, R. D. (2011). "Irlen colored overlays do not alleviate reading difficulties". Pediatrics. 128 (4): e932-8. doi:10.1542/peds.2011-0314. PMID 21930551. S2CID 27034274.
  10. ^ Irlen, HL. "Scotopic sensitivity? Irlen syndrome: hypothesis and explanation of the syndrome". Journal of Behavioral Optometry. 5 (62): 65–66.
  11. ^ "Archived copy". Archived from the original on 25 January 2014. Retrieved 2014-03-28.{{cite web}}: CS1 maint: archived copy as title (link)
  12. ^ "Archived copy". Archived from the original on 25 January 2014. Retrieved 2014-03-28.{{cite web}}: CS1 maint: archived copy as title (link)
  13. ^ "Society for Coloured Lens Prescribers".
  14. ^ "The University of Newcastle, Australia". 13 November 2015. Archived from the original on 12 January 2007.
  15. ^ "American Academy of Pediatrics, 2009".
  16. ^ Hyatt, KJ (2010). "Irlen Tinted Lenses and Overlays" (PDF). MUSEC Briefings. Macquarie University Special Education Centre. 22.
  17. ^ Solan H, Richman J (1990). "Irlen lenses: a critical appraisal". J Am Optom Assoc. 61 (10): 789–96. PMID 2136527.
  18. ^ "The Use of Tinted Lenses and Colored Overlays for the Treatment of Dyslexia and Other Related Reading and Learning Disorders". Archived from the original on 2 October 2009. Retrieved 13 October 2009.
  19. ^ Keith j. Hyatt; Jennifer Stephenson; Mark Carter (2009). "A Review of Three Controversial Educational Practices: Perceptual Motor Programs, Sensory Integration, and Tinted Lenses". Project MUSE - Education and Treatment of Children. 32 (2): 313–342. doi:10.1353/etc.0.0054. S2CID 143983625.
  20. ^ Hoyt CS (December 1990). "Irlen lenses and reading difficulties". J Learn Disabil. 23 (10): 624–6. doi:10.1177/002221949002301010. PMID 2280171. S2CID 30863520.
  21. ^ Parker RM (December 1990). "Power, control, and validity in research". J Learn Disabil. 23 (10): 613–20. doi:10.1177/002221949002301008. PMID 2280169. S2CID 21369939.
  22. ^ Solan HA (December 1990). "An appraisal of the Irlen technique of correcting reading disorders using tinted overlays and tinted lenses". J Learn Disabil. 23 (10): 621–3, 626. doi:10.1177/002221949002301009. PMID 2280170. S2CID 40223496.
  23. ^ Blaskey P, Scheiman M, Parisi M, Ciner EB, Gallaway M, Selznick R (December 1990). "The effectiveness of Irlen filters for improving reading performance: a pilot study". J Learn Disabil. 23 (10): 604–12. doi:10.1177/002221949002301007. PMID 2280168. S2CID 32063320.
  24. ^ O'Connor PD, Sofo F, Kendall L, Olsen G (December 1990). "Reading disabilities and the effects of colored filters" (PDF). J Learn Disabil. 23 (10): 597–603, 620. doi:10.1177/002221949002301006. PMID 2280167. S2CID 19142994. Archived from the original (PDF) on 20 September 2010.
  25. ^ Robinson GL, Conway RN (December 1990). "The effects of Irlen colored lenses on students' specific reading skills and their perception of ability: a 12-month validity study". J Learn Disabil. 23 (10): 589–96. doi:10.1177/002221949002301005. PMID 2280166. S2CID 37587288.

Further reading[edit]

  • Hyatt, Keith J (February 2010). "Irlen Tinted Lenses and Overlay" (PDF). MUSEC Briefings. Macquarie University Special Education Centre (22). Archived from the original (PDF) on 29 August 2017. Retrieved 22 April 2017.
  • Wilkins, Arnold J. (2003). Reading through color: how colored filters can reduce reading difficulty, eye strain, and headaches. Chichester: John Wiley & Sons. ISBN 0-470-85116-3. OCLC 78883050.