Type for Impaired Eyes

Thomas Bohm is a designer from Leicester College, England, whose studio User Design, Illustration and Typesetting works for book publishers and businesses, and is a graphic communication design, illustration and production service. He is the author of Published Punctuation..? (2nd edition, User Design, 2012), a fully illustrated book on punctuation. His paper Letter and symbol misrecognition in highly legible typefaces for general, children, dyslexic, visually impaired and ageing readers (2016, 2nd edition) recently caught my interest, particularly regarding the aging part. This is from his introduction:

Incorrect recognition of a letter or symbol can occur in a number of different situations, whether it be an unclear typeface, reading a book or at long distance reading a road sign, to more serious instances, like medicine information leaflets or on a display in an aircraft. Different people (general, children, dyslexic, visually impaired, ageing) also have specific letter and symbol requirements. Which letters and symbols are the most problematic and how are letters and symbols to be designed for maximum recognition clarity?

The word ‘legible’ used in this paper refers to typefaces which have well defined easily recognizable letters and symbols, which can be decoded easily and quickly, which are not overly stylistic in letterform design, typically typefaces used in the context of continuous reading, not script typefaces.

I asked him to tell us more.

You are obviously a full-service design service, but how did the study of misrecognition become a focal point?
When I was studying graphic communication design (specializing in design for publishing) at university, I had seen in a book the comparison between the word ‘Illustration’ set in sans serif and serif typefaces; the capital I (i) and two lowercase l’s (el) in the sans serif looked the same. Years later around 2009 still using my old Nokia mobile phone (the typeface on the phone was not the typeface designed for Nokia by Erik Spiekermann) I noticed the same issue regarding the capital I (i) and lowercase l (el). So in 2009 I started to write about these issues and try to expand on them.

What was your research methodology?
I like to read about graphic communication design, information design, typography, user testing and generally anything to do with effective graphic communication. Over the years I had read some interesting articles on typography and as such decided to build them into this issue of a lack of definition between the capital I (i) and lowercase l (el). I do not consider the paper to be absolutely mandatory or authoritative, just a review and discussion of related research. It involved going back over previously read papers and research and trawling through loads of new papers. There was also research and information which I decided not to include due to poor backup information (see my points regarding dismissed dyslexic research in the conclusion, and weak and strong testing results information, again in the conclusion).

Here is an excerpt:

The following letters can be easily confused as other characters: lowercase l (el) can be read as the number 1 or a capital I (i). The capital I (i) can be read as a lowercase l (el) or as a number 1. The number 1 can be read as a lowercase l (el), capital I (i), or number 7 (Figure 1).


Figure 1. Typefaces: Bucko and Sassoon Infant.

Did you determine that children with dyslexia and other learning disabilities can actually benefit from typographical nuances?
I never discussed children with dyslexia, just children on their own without any other issues, and then for people with dyslexia (mainly adults). Good question. There is research and typefaces for people [not specifically children with dyslexia] with dyslexia that shows, in the case of Sylexiad and Dyslexie, that these two typefaces resulted in a better experience for people with dyslexia (more details can be found in their research); then you have other people who say specific dyslexic typefaces have no impact on performance (see Chuck Bigelow’s comment in the conclusion of my paper). There is also research referenced to by Beier & Larson, 2010, and by Smuc et al., 2007, and by Chaparro et al, 2011, at the beginning of my paper that highlights even general adults misrecognize letters and symbols, so what hope is there for people who are using information under less than ideal setup?

Here is an excerpt:

The United Kingdom car number plate in Figure 4 shows a letter which is not in a normal alphabet. What does it stand for? I have been unable to find out. From comments, Riccardo Sartori suggests it is a capital L rotated 180 degrees to form the letter/number which symbolises a number 7.


Figure 4. Letter on car number plate not in normal alphabet. Top typeface: English car number plate typeface ‘Mandatory,’ bottom typeface: German car number plate typeface ‘FE-Schrift.’

What did you discover that is new between your initial findings and the second paper on the theme?
What I can say is that I have tried to present a considered overview of issues and that in the second edition I tried to reduce the amount of errors in previous editions of the paper and to improve everything, including my own statements. I also discovered that it is tricky to write about typography and related research; it takes years of editing and research to get writing on design up to a good standard. We also need more research in regard to issues discussed in the paper and better testing information of typefaces from people. “What did you discover that is new?” I discovered testing typefaces with people is tricky!

Are symbols more or less recognizable for people with impairment?
The issue of misrecognition is heightened/stressed even more for people who do not have ideal eyesight or who have dyslexia.

Can this issue be solved on a large scale or must it be customized to the individual?
Ultimately it lies within the typeface design itself. I think there are things we can do to enable (stack in favor of) effectiveness for most, but in the case of dyslexia there are so many issues and issues that different dyslexic people have, it could be hard to produce a 100%-fits-all.

Here is an excerpt:

The many different eye conditions affect people in different ways. Three common eye conditions are glaucoma, diabetic retinopathy and macular degeneration (Figure 21). Glaucoma can result in tunnel vision, where all side vision is lost and only central vision remains. Diabetic retinopathy can cause blurred and patchy vision. Macular degeneration can lead to a loss of central vision while side vision remains. But everyone is affected in different ways, and it is important not to assume that you know what someone can see simply because you know which eye condition she/he has (RNIB, 2006). The vast majority of people with sight problems are aged 65 and over (Tiresias, 2009). Another common term which gets used also within the area of visual impairments is low vision; low vision is defined as visual impairments that are not correctable through surgery, pharmaceuticals, glasses or contact lenses (The Vision Council, 2015).


Figure 21. Three common eye conditions. Photo credit: Action for Blind People. (Click to enlarge)

What is your hope for the outcome?
Maybe that certain letters and symbols (highlighted in the paper) in future typefaces are defined/differentiated better. I do not want to dictate what should or should not be done. There is also the aspect of inclusiveness (including different types of people) in regard to typeface design (maybe my paper highlights that there are people other than able designers who are worth considering in the design process). It is the general public that will most likely use their designs. Also, how should we test typeface designs with people?


PRINT’s Typography & Lettering Competition—Enter Now

All too often, typography gets overlooked in larger design competitions—which is why we developed one that gives the artforms their full due and recognizes the best designers in each category. Whether you design your own typefaces, design type-centric pieces or create gorgeous handlettered projects, we want to see your work—and share it with our readers.

Enter today for a chance to be featured in Print magazine, receive a prize pack from MyDesignShop.com, and more.


One thought on “Type for Impaired Eyes

  1. fritter

    Mr. Heller

    There is no discussion here about context. The examples above are pretty unique in this rather instantaneous, non-contextual integration of figures and letter forms. If given a normal integration or context of figure to letter, do these impairments persist in causing misrecognition of letters and figures? –Or for that matter, in people who do not suffer from these impairments?

    Thank you.