A team of researchers in Spain has recently published the results of a study to determine which fonts were easiest for dyslexic individuals to read. Based on the evaluation of 48 dyslexic subjects ages 11-50, reading 12 texts with 12 different fonts, they determined that reading performance was best with sans serif, monospaced, and roman fonts used in the study. They also found that reading was significantly impaired when italic fonts were used.
The researchers included Arial and Times because they are the most common fonts used on screen and printed texts, and included Courier as the most common monospaced font. OpenDyslexic was selected because is a freely distributed font specifically designed to assist dyslexic readers. The study included the italic forms as well as regular forms of those three fonts.
They researchers also included Verdana, a sans serif face, because that font is often recommended for improved readability. Other fonts included Garamond, because it is reputed to have strong legibility; Helvetica and Myriad, which are broadly used in graphic design; and Computer Modern Unicode, which is widely used in scientific publishing.
To determine readability of text, the researchers measured both reading time, and fixation duration using eye tracking data, while subjects read carefully selected 60-word paragraphs. Subjects were also asked to indicate their own preferences, ranking each font on a 1 to 5 scale.
Use of the OpenDyslexic font did not enhance text readability or reading speed. The study participants strongly preferred Verdana or Helvetica over the OpenDyslexic alternative. Based on their findings, the researchers recommended Helvetica, Courier, Arial, Verdana and Computer Modern, based both on reading performance and subjective preference; and cautioned against the use of italic texts.
As someone who has wrestled with the issue of font choice and legibility for years, I was not surprised at the poor performance of OpenDyslexic. Although the font has been widely promoted as being designed for dyslexics, I find the font clunky and difficult to read, and others I have talked to had mixed reactions (some liked it, others not).
At the same time, I question an assumption underlying the researchers’ conclusion that font design is paramount. It seems to me that their research showed simply that the most commonly used fonts were also the ones that were the easiest for their subjects to read. I remember how my son struggled as child with cursive, and his own insistence for using 14 pt. Times New Roman for all of his own written work. I think familiarity with the type face and individual letter forms may be particularly important for dyslexic readers. It may be that dyslexics are far more sensitive to minor variations in letter shape, form, and spacing. That they did best with the font sets that they were most likely to have been exposed to in the past does not necessarily mean that those fonts are the best for everyone.
You can read the study here:
- Good Fonts for Dyslexia (Luz Rello and Ricardo Baezo-Yates)
You can experiment with some of the fonts used in the study, including Arial, Verdana, Times Roman, and OpenDyslexic, by using the Change Font function on the Dyslexia.com Site Customization page. I personally prefer Lexia Readable, an alternative free font designed with dyslexics in mind, and Trebuchet, which were not included in the study. Please note that you may have to download some fonts if they are not already included on your computer, particularly if you want to try the Lexia or OpenDyslexic fonts.