Irlen.wikiAn independent record of the Irlen Institute, the Irlen Method and the evidence about them

Glossary

From Irlen.wiki, an independent record of the Irlen Institute, its colored overlays and filters, and what researchers say

Researched and compiled by the Irlen Wiki editorial team · First published · Revised

In brief: Sourced definitions of the terms used on this site, from “colored overlay” to “visual stress.”[1][10]

A note on independence: Irlen.wiki is an independent record compiled from irlen.com, irlensyndrome.org, public records and published research. It is not operated by the Irlen Institute, sells nothing and gives no medical or educational advice. The Institute’s statements are attributed to it and shown beside independent assessments. Sourcing rules: editorial policy.

Terms used on this site

Short, sourced definitions of the terms used across this reference. Institute product names are given as the Institute uses them; clinical terms follow professional sources.[18][10]

Colored overlay
A transparent colored plastic sheet laid over print; Irlen overlays come in ten colors.[1]
Diagnostician (Irlen)
A practitioner certified by the Institute to run both testing sessions and choose filter tints.[2]
Dyslexia
A language-based learning disability affecting reading, usually from a phonological deficit.[3]
Irlen Clings
Adhesive Irlen overlays for phones, tablets and computer screens.[1]
Irlen Method
The Institute’s two-session process of screening with overlays and tinting lenses.[4][5]
Irlen Spectral Filters
Individually tinted glasses or contact lenses sold through Irlen diagnosticians.[6]
Irlen syndrome
A proposed visual processing condition named by Helen Irlen; not a recognized medical diagnosis.[7]
Joint statement
The statement on learning disabilities, dyslexia and vision by U.S. pediatric and ophthalmology bodies (2009, revised 2011).[8][3]
Meares-Irlen syndrome
A name crediting Olive Meares’s early descriptions alongside Irlen.[9]
MISViS
Meares-Irlen syndrome/visual stress, an umbrella label used by EyeWiki.[10]
Discomfort and distortion provoked by repetitive patterns such as lines of text; a research concept distinct from the Irlen assessment.[10]
Photophobia
Discomfort from light; it has many medical causes.[11]
Placebo control
A comparison condition, such as a non-prescribed tint, used to separate real effects from expectation.[12][13]
RANZCO
The Royal Australian and New Zealand College of Ophthalmologists, which issued statements on Irlen lenses in 2018 and 2025.[14][13]
Refractive error
Focusing errors such as short or long sight, corrected with ordinary glasses; can cause similar symptoms.[13]
Scotopic sensitivity syndrome
Helen Irlen’s earlier name for the condition.[15]
Screener (Irlen)
A practitioner certified to run the first session and choose overlays.[2]
Screening session
The first Irlen session, which rates symptoms and selects an overlay.[16]
Systematic review
A structured review of all available studies on a question, such as the 2019 review of Irlen syndrome.[17]
Tint assessment
The second Irlen session, in which a diagnostician chooses the lens tint.[16]
Visual stress
A broader term for reading-related visual discomfort; the Irlen organizations treat it as equivalent to Irlen syndrome, EyeWiki does not.[9][10]

Names for the condition

The several names for the condition, and why they are not interchangeable, are explained on names and terminology.[9][10] The two testing sessions are described on the Irlen Method.[5]

Usage notes

This reference writes “Irlen syndrome” in lower case, as encyclopedias do, and “Irlen Syndrome” when quoting the Institute, which capitalizes it.[7][15] “Treatment” is used only when reporting the Institute’s or a study’s wording; the Institute itself says its filters are not medical treatment.[16]

Common questions

What is an Irlen overlay?

A transparent colored plastic sheet placed over print.

What is a tint assessment?

The second Irlen session, where a diagnostician chooses a lens tint.

What is visual stress?

A broader term for reading-related visual discomfort studied outside the Irlen system.

Further pages

Citations

  1. ^ a b c Irlen colored overlays. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  2. ^ a b Find an Irlen testing center. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  3. ^ a b Learning disabilities, dyslexia, and vision. Pediatrics 127(3):e818–56 (2011). Handler SM, Fierson WM et al., via PubMed. Retrieved 9 November 2026.
  4. ^ The Irlen Method. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  5. ^ a b Testing & treatment. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  6. ^ Irlen colored filters. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  7. ^ a b Irlen syndrome. Wikipedia. Retrieved 9 November 2026.
  8. ^ Joint statement: learning disabilities, dyslexia, and vision. Pediatrics 124(2):837–44 (2009). American Academy of Pediatrics, American Academy of Ophthalmology, AAPOS and AACO, via PubMed. Retrieved 9 November 2026.
  9. ^ a b c Everything you need to know about the different names for Irlen Syndrome (4 March 2022). Irlen Syndrome Foundation (irlensyndrome.org). Retrieved 9 November 2026.
  10. ^ a b c d e f Meares-Irlen syndrome/visual stress (MISViS), reviewed 25 September 2026. EyeWiki, American Academy of Ophthalmology. Retrieved 9 November 2026.
  11. ^ Photophobia. Wikipedia. Retrieved 9 November 2026.
  12. ^ Irlen colored overlays do not alleviate reading difficulties. Pediatrics 128(4):e932–8 (2011). Ritchie SJ, Della Sala S, McIntosh RD, via PubMed. Retrieved 9 November 2026.
  13. ^ a b c RANZCO position statement on Irlen lenses (2025). Royal Australian and New Zealand College of Ophthalmologists. Retrieved 9 November 2026.
  14. ^ No scientific evidence that Irlen Syndrome exists, say ophthalmologists (2018). Royal Australian and New Zealand College of Ophthalmologists. Retrieved 9 November 2026.
  15. ^ a b The science. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  16. ^ a b c FAQs. Irlen Institute (irlen.com). Retrieved 9 November 2026.
  17. ^ Irlen syndrome: systematic review and level of evidence analysis. Arq Neuropsiquiatr 77(3):194–207 (2019). Miyasaka JDS et al., via PubMed. Retrieved 9 November 2026.
  18. ^ The Irlen Institute: home page. Irlen Institute (irlen.com). Retrieved 9 November 2026.