For low vision specialists and those who consult them
Font effects in low vision: the effect is surprisingly small
July 23, 2009Posted by on
One of my friends in web development told me authoritatively “you should use sans serif fonts to make websites easier to read by people with visual problems.” It seems that this is a reasonably widely held view, but the research doesn’t really back this claim up. Indeed, the choice of font is of very little importance on legibility for people with low vision.
In a group of people with low vision, Rubin and colleagues did not find any difference in reading speed between four different fonts provided that character size was properly controlled for (Rubin, Feely, Perera, Ekstrom & Williamson, Ophthalmic & Physiological Optics, 2006). Interestingly, one of those fonts was specifically designed for people with low vision (Tiresias) but this did not really improve reading ability.
In a study of older adults with normal vision reading on a computer screen, another study did not find any difference in reading speed between four commonly used fonts (Bernard, Liao & Mills, Conference on Human Factors in Computing Systems, 2001).
Arditi and colleagues at Lighthouse International in New York have developed a software system for bespoke font construction for people with low vision. Using this system, people can alter many parameters of text such as letter spacing, the type of serifs (decorative elements at the end of each letter, such as those at the end of the top bar in a letter “T” in the Times New Roman font) and ascender or descender height. Whilst there is a significant variability between subjects in the typeface they select, these bespoke fonts do not appear to improve reading above that for common fonts such as Times New Roman (Arditi, Ergonomics, 2004).
Over the 600 year history of printing, typefaces may well have evolved such that the most readable fonts have survived, whilst less readable typefaces such as Blackmore have fallen out of favour.
Advice for web developers: use high colour contrast, high contrast text, use a predictable text format (e.g. left aligned) and most importantly, use good coding practice so that people with screen readers can manipulate the text as they desire. But don’t get hung up on what font to use.