19 Mar 2024
**Numbers annotated in brackets refer to relevant citations, available at the end of the post.**
In 1990, the researchers from The Global Burden of Disease Study started to assess the prevalence of vision impairment. This study went on until the year 2020, and within those three decades, they unfortunately found a staggering increase of 91.7% for people with moderate to severe vision impairment, along with 50.1% increase of blindness (1).
To put it into perspective, there’s currently AT LEAST 2.2 billion people dealing with near or distance vision impairments (2), of which almost half of them could’ve been prevented.
Vision impairment in children
Regardless of one’s age, vision impairment(s) can pose quite a significant impact on their quality of life (QoL). However, especially for the millions of children currently in need of treatment for their sight condition (3), or even living with vision loss, the consequences could potentially get even more serious.
For instance, young children who experience severe vision impairment at an early age and are left without sight correction could experience development delays in areas such as language, social, motor, and cognitive abilities; which includes reading. School-age children with vision impairment may then experience lower-levels of academic success (1). A study conducted in Spain of children aged between 6 and 12 years old found that children with lower academic results have worse visual health than their peers with normal visual health (4).
Additionally, a longitudinal 8 years-study in 2017 found that on average, students with vision impairments lag behind in reading development by 2 years (5). One of the reasons why this occurs is because children with visual deficiencies are only properly exposed to print and reading strategies later than their sighted peers.
What about adults?
For adults, this constitutes a much lower level of Reading Accessibility Index (ACC), which is a measure of an individual’s access to text across type sizes in the day-to-day. It is measured by calculating the average reading speed and reading acuity (RA) across different print sizes.
In the example shown below, a study published by JAMA Ophthalmology comparing the ACC of normal-sighted adults and adults with visual impairment shows a very pronounced difference. Where the average normal sighted individuals have an ACC index of 1.0, their visually-impaired counterparts have a severely reduced ACC index of 0.12 (6).
Image: E. Legge, G. (2016). Reading Digital with Low Vision. Visible Lang. , Adapted from Calabrèse et al. (2016)
Thus, we can now ask THE question:
What can we do to help improve the reading experience of visually-impaired individuals?
Reading is a very complex cognitive process that humans have only developed around 5,000 years ago, with the first recorded written language from 3,500 BCE, such as this cylinder seal created by the Sumerians (8).
Image: Met Museum. (n.d.). Cylinder seal and modern impression: hunting scene. https://www.metmuseum.org/art/collection/search/329090
And so we do not have 100%, complete understanding (yet!) on how reading actually works, but there are several theories on the general process. But to prevent this post from going too long, we will keep these theories for next time.
So now, back to the question: What can we do?
Typography, readability, and legibility affect one another. Here’s an extreme example:
Comparing these three typefaces, normally, you would read one with more ease and/or less eye strain than the other. If this is not the case for you, please message me as I would be very interested to discuss further.
Nonetheless, it is also a fact that typography, or type design can’t be the ONLY solution for the reading experience of the visually-impaired. But they can definitely, to a certain extent, affect it. As designers and typographers, we can do the simple manipulations to ease or help the reading process, such as:
choosing at least a “convenient” typeface (this is yet another very nuanced subject for another post),
make it bolder,
with wider tracking (letter-spacing),
plus wider leading (line-spacing),
lastly…magnification!
But…
With the technology that we have now, we can go a bit further, maybe something more customised for each particular type of vision impairment. Of course, with the sea of typefaces that we have, you might ask: “Why don’t we just choose one out of the thousands?”
A quote by Gerard Unger would answer this question:
“Typefaces are designed for specific purposes, for a particular kind of publication or content, to fit an identity or to be economical, but legibility is usually retained at best and not improved”
- Gerard Unger, Theory of Type Design, 2018
There have actually been some instances where typefaces were created with the goal of increasing legibility and readability for visually-impaired patients. However for today, we are focusing on certain visual parameters and how they could affect one another.
Stroke contrast & serifs
Sofie Beier and Katsumi Minakata recently published a study in which they investigated the effect of both stroke contrast and serifs. Four test materials were created for this study to really isolate the effects of these letter features on reading performance. (7)
Image: Minakata, K., & Beier, S. (2022). The dispute about sans serif versus serif fonts: An interaction between the variables of serif and stroke contrast. Acta Psychologica, 228.
They ran two experiments: word-recognition and lexical decision tasks with participants who have normal vision and corrected-to-normal vision.
And it was found that smaller type sizes were read with:
Sans-serif type with low-stroke contrast; and
Serif type with high-stroke contrast
During her talk at ATypI Paris 2023, Sofie Beier further explained that the contrary would apply for visually-impaired individuals (NOT corrected-to-normal); they fared better with:
Sans-serif type with high-stroke contrast; and
Serif type with low-stroke contrast
It is important to note that in this experiment, there were no particular typefaces compared, rather only focusing on the letters’ characteristics (stroke contrast & serifs).
This actually aligns with what Gerard Unger stated as well:
“If legibility can be changed for the better, then it is with small and barely perceptible steps.”
But why shall we put an emphasis on this?
In this digital age where social media is part of a lot of people’s daily lives, deep, immersive activity such as reading would take the back seat.
Already, our attention span is continuously consumed by the constant bombardment of contents across social media platforms. Distractions pull our attention left and right, battling for our attention, and it’s no wonder that we feel like we don’t have much attention span left — because we have used them up without even noticing.
Imagine then, to double it with the discouragement from having visual impairment, reading could potentially be on the absolute backburner. Of course, typography is NOT the ONLY solution to this, and could never be. Regardless, with massive technological advancements on the horizon, we as designers and typographers can, hopefully, work in cross-domain to help create a more accessible future, one letter, or character, at a time.
Stay tuned for my next post!
Studies cited:
The Global Burden of Disease Study. (2021, March 29). Vision Impairment Prevalence Increases as Population Ages. Review of Optometry. https://www.reviewofoptometry.com/news/article/vision-impairment-prevalence-increases-as-population-ages
World Health Organization . (2022, October 13). Blindness and vision impairment. WHO. https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment
Child eye health. The International Agency for the Prevention of Blindness. (2022, August 23). https://www.iapb.org/learn/vision-atlas/magnitude-and-projections/child-eye-health/
Alvarez-Peregrina, C., Sánchez-Tena, M. Á., Andreu-Vázquez, C., & Villa-Collar, C. (2020, March 31). Visual Health and Academic Performance in School-Aged Children. National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177927/
Boroson, B., Barker, E., & Li, X. (2017). A Longitudinal Study of Reading Growth for Students with Visual Impairments. The Journal on Technology and Persons with Disabilities, 5, 158–171.
Calabrèse A, Owsley C, McGwin G, Legge GE. Development of a Reading Accessibility Index Using the MNREAD Acuity Chart. JAMA Ophthalmol. 2016 Apr;134(4):398-405. doi: 10.1001/jamaophthalmol.2015.6097. PMID: 26868760; PMCID: PMC5369600.
Minakata, K., & Beier, S. (2022). The dispute about sans serif versus serif fonts: An interaction between the variables of serif and stroke contrast. Acta Psychologica, 228. https://doi.org/https://doi.org/10.1016/j.actpsy.2022.103623
Samara, T. (2018). Heritage. In Letterform: Typeface design from past to future (p. 12). Quarto Publishing Group.
