Dyslexia is a learning difficulty that causes problems with reading, writing and spelling. It affects 3-7% of the world’s population,1 making it one of most common learning difficulties.2
Accessibility is an important part of good web design, and many designers and developers find themselves looking to accommodate users with dyslexia.
In recent years, a handful of fonts have been produced that are designed to enhance readability for those with dyslexia. Examples of these fonts are Sylexiad, Dyslexie, Read Regular, and the free and open source OpenDyslexic.
There is a Chrome extension available that allows text to be rendered in the OpenDyslexic font, and the font is available as an option on major websites such as Wikipedia, as well as on Amazon’s Kindle e-readers.
But are these fonts able to mitigate the issue dyslexic users experience? Do these fonts work?
The answer, it seems, is no.
The Science
Multiple scientific studies and investigations have failed to demonstrate an increase in reading performance when dyslexic individuals are shown text set in these ‘dyslexic-friendly’ fonts.
In Good Fonts for Dyslexia, researchers from the University of Michigan aimed to “objectively measure the impact of the font type on reading performance” with the use of eye-tracking technology. Forty-eight subjects with dyslexia read 12 pieces of text in 12 fonts. They found no change in readability with fonts designed for those with dyslexia; there was no improvement or reduction in readability.3
A paper published in Annals of Dyslexia in April 2018, titled Dyslexie font does not benefit reading in children with or without dyslexia, concluded the Dyslexie font did not help dyslexics read faster or more accurately: “These experiments clearly justify the conclusion that the Dyslexie font neither benefits nor impedes the reading process of children with and without dyslexia”.4
So what fonts are good for those with dyslexia?
The British Dyslexia Association recommend “plain, evenly spaced sans serif font such as Arial and Comic Sans. Alternatives include Verdana, Tahoma, Century Gothic, Trebuchet”.5
The results of Good Fonts for Dyslexia back up these recommendations: “Good fonts for people with dyslexia are Helvetica, Courier, Arial, Verdana and CMU”.
The recommendation of Arial is further corroborated by Renske de Leeuw’s Master’s thesis published in 2010. Titled Special Font For Dyslexia?, the thesis compared Dyslexie to Arial in reading tests of dyslexic and non-dyslexic readers. The results found subjects read one more word per minute with Arial than Dyslexie (80.0 vs 79.0).6
Conclusion
Good fonts for those with dyslexia are Arial, Verdana, Tahoma and Trebuchet.
There is no scientific evidence that so-called ‘dyslexic-friendly’ fonts like OpenDyslexia or Dyslexie enhance readability or improve reading performance in those with dyslexia.
Multiple scientific studies have failed to show any benefit, and some have even demonstrated a reduction in performance using these fonts.
References
1 – Developmental dyslexia (PDF)
2 – Learning Disabilities: Condition Information
3 – Good Fonts for Dyslexia (PDF)
4 – Dyslexie font does not benefit reading in children with or without dyslexia
5 – Dyslexia Style Guide (PDF)
6 – Special Font for Dyslexia? (PDF)