Inter-letter spacing, inter-word spacing, and font with dyslexia-friendly features: testing text readability in people with and without dyslexia

Ann Dyslexia. 2020 Apr;70(1):141-152. doi: 10.1007/s11881-020-00194-x. Epub 2020 Mar 14.


Over the last years, several studies have suggested a possible link between dyslexia and deficits in low-level visual processing (e.g., excessive crowding). At the same time, specially designed "dyslexia-friendly" fonts appeared on the market. This class of fonts presents two main features: the particular graphic characteristics of the letterform designed to avoid confusion between similarly shaped letters, and wider inter-letter and inter-word spacing to limit crowding. The literature testing the efficacy of "dyslexia-friendly" fonts in improving reading accuracy and increasing reading speed is controversial. We evaluated the impact of letterform (with vs. without dyslexia-friendly graphic features), inter-letter spacing (standard vs. increased), and inter-word spacing (standard vs. increased) on reading accuracy and speed. Two groups of 64 children each, with and without dyslexia, read aloud 8 equivalent texts. The data collected failed to show any effect from the letterform. As regards spacing, the data showed that reading speed is impaired by an increase in inter-letter spacing not combined with an adequate increase in inter-word spacing.

Keywords: Dyslexia; EasyReading; Font; Letter spacing; Reading.

Publication types

  • Comparative Study

MeSH terms

  • Child
  • Comprehension / physiology
  • Dyslexia / psychology*
  • Dyslexia / therapy
  • Female
  • Humans
  • Male
  • Pattern Recognition, Visual / physiology*
  • Photic Stimulation / methods*
  • Reading*
  • Visual Perception / physiology