The Effect of Font Type on Screen Readability by People with Dyslexia
Luz Rello, Ricardo Baeza-Yates · 2016 · ACM Transactions on Accessible Computing · doi:10.1145/2897736
Summary
This eye-tracking study investigates how different font types affect screen reading performance for people with dyslexia compared to non-dyslexic readers. The researchers recruited 97 native Spanish speakers—48 diagnosed with dyslexia and 49 without—to read short texts displayed in 12 different fonts while their eye movements were tracked. The fonts tested spanned multiple typographic categories: sans-serif (Arial, Helvetica, Verdana, Myriad), serif (CMU, Garamond, Times), monospaced (Courier), italic variants (Arial Italic, Times Italic), and fonts specifically designed for dyslexia (OpenDyslexic, OpenDyslexic Italic). Each participant read texts in all 12 fonts, with researchers measuring reading time, fixation duration, number of fixations, and subjective preference ratings. The study design allowed systematic comparisons between font style categories (serif vs. sans-serif, italic vs. roman, monospaced vs. proportional, and dyslexia-specific vs. standard fonts) to identify which typographic features most impact readability for dyslexic readers.
Key findings
The study found that font type significantly affects reading performance for both groups, but participants with dyslexia showed consistently longer reading times and fixation durations across all fonts. The best-performing fonts for objective readability were Helvetica, Courier, Arial, and CMU, which produced shorter fixation durations for dyslexic readers. Crucially, Arial Italic performed worst across nearly all measures and should be avoided—italic fonts generally led to significantly worse reading performance than their roman counterparts. Sans-serif fonts outperformed serif fonts for participants with dyslexia, and monospaced fonts (Courier) led to shorter fixation durations. Perhaps most surprisingly, OpenDyslexic—a font specifically designed for dyslexic readers—did not outperform standard sans-serif fonts like Arial, Helvetica, or Verdana on any measure. Both groups showed strong preference for Verdana, Helvetica, and Arial. The study also revealed that fonts beneficial for dyslexic readers were equally good for non-dyslexic readers, suggesting inclusive typography benefits everyone.
Relevance
These findings have direct implications for web developers, designers, and content creators making typography decisions. The recommendation to use Arial, Courier, CMU, Helvetica, or Verdana with roman (non-italic) styles provides actionable guidance for accessible design. The finding that dyslexia-specific fonts like OpenDyslexic offer no measurable advantage over well-designed standard fonts is particularly valuable—organizations need not seek specialized fonts when common web-safe options perform equally well or better. The study reinforces WCAG guidance on text presentation and provides empirical evidence that italic text creates accessibility barriers. For practitioners, the key takeaway is straightforward: use sans-serif, roman, or monospaced fonts; avoid italics, especially Arial Italic; and recognize that good typography for dyslexia benefits all users.
Tags: dyslexia · typography · readability · eye tracking · font design · cognitive accessibility
Standards referenced: WCAG 2.0