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Fonts + Design
Snellen Optotype Font with Upper and Lowercase characters
In the process of designing my Snellen Eye Chart typographical posters, I came across the Snellen font by Andrew Howlett. I wasn't happy with all the letters, so I made attempts at giving the font an update. I call this redesign "Snellen MK", to avoid conflict with Howlett's "Snellen".
Not being a font designer, I will likely get myself into trouble.
snellen chart posters
While making my Snellen chart series, I entered the rabbit hole of optotype fonts ... and I can't get out!
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The charts don't necessarily use the latest version of my Snellen font design, which fluctuates as my mood about some of the letters changes.
optotype fonts
The optotype requirement is that letters be designed on a 5 × 5 grid, and have constant stroke width. This means that both lower and upper case letters need to share the grid and stroke. To stay compatible with the eyechart paradigm, letters should be as obvious as possible.
Lorrie Frear's article What are Optotypes? Eye Charts in Focus is a great read about optotypes and eye charts.
Snellen Optotype Letter Design
uppercase
The uppercase letter design uses Herman Snellen's original chart as inspiration.
I have modified the design by Andrew Howlett (see below) for some letters. All the changes are relatively minor: more serifs and consistent stroke width for bars on R and K.
lowercase
The lowercase characters should be considered experimental.
The progress of my redesign is shown below. I would greatly appreciate feedback and suggestions!
Download SnellenMK Optotype Font
The distribution contains both Andrew's version and my redesign.
v7.002 11-Jul-2019 — Download SnellenMK optotype font
version v7.002 11-Jul-2019
Tidied all letter forms with Fontlab 6.
version 7 — 6 Feb 2017
Fixed g and e. Thanks to Makeesha Fisher for suggestions.
version 6 — 5 Feb 2017
Adjusted serifs on f, j, l, o, t to extend the full width of the grid. Added a lot more symbols.
version 5 — 4 Feb 2017
Added lowercase, digits and symbols.
version 4 — 23 Feb 2017
Adding digits.
version 3 — 22 Feb 2017
I'm exploring the lowercase characters. I don't know what I want to do with them. Make this into a more standard font in which lowercase letters are smaller, so that letters can fit their roles clearly when text is set in sentence case, or fill out the full optotype grid.
version 2 — 22 Feb 2017
Flushed out some inconsistencies in the uppercase characters. Added serifs to more letters.
Now all the letters occuppy the full 5 × 5 grid, including the I, whose serifs were widened to allow this. While this new uppercase I isn't as pretty as the old one, it makes the entire typeface more consistent to its optotype roots.
Still struggling with the G. In the original version, the descending stroke was cut off in the middle of a grid, which I didn't like.
The S has been fixed—thanks to Elanor Lutz for feedback.
I've color coded the characters slightly differently, drawing attention to ones that I feel need more thought.
The lowercase characters aren't color coded (yet) because ... most of them need help. Primarily, I'm vacillating between making them fill the full size of the 5 × 5 square, just like the uppercase characters, and keeping them confined to a 4 × 4 square, which incurs loss of legibility. If I make the letters the same size, it will be impossible to distinguish lowercase and uppercase characters some cases (e.g. c, i). Perhaps this is desired?
version 1 — 22 Feb 2017
First attempt at lowercase characters.
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news + thoughts
Happy 2021 `\pi` Day—
A forest of digits
Celebrate `\pi` Day (March 14th) and finally see the digits through the forest.
This year is full of botanical whimsy. A Lindenmayer system forest – deterministic but always changing. Feel free to stop and pick the flowers from the ground.
And things can get crazy in the forest.
Check out art from previous years: 2013 `\pi` Day and 2014 `\pi` Day, 2015 `\pi` Day, 2016 `\pi` Day, 2017 `\pi` Day, 2018 `\pi` Day and 2019 `\pi` Day.
Testing for rare conditions
All that glitters is not gold. —W. Shakespeare
The sensitivity and specificity of a test do not necessarily correspond to its error rate. This becomes critically important when testing for a rare condition — a test with 99% sensitivity and specificity has an even chance of being wrong when the condition prevalence is 1%.
We discuss the positive predictive value (PPV) and how practices such as screen can increase it.
Altman, N. & Krzywinski, M. (2021) Points of significance: Testing for rare conditions. Nature Methods 18
Standardization fallacy
We demand rigidly defined areas of doubt and uncertainty! —D. Adams
A popular notion about experiments is that it's good to keep variability in subjects low to limit the influence of confounding factors. This is called standardization.
Unfortunately, although standardization increases power, it can induce unrealistically low variability and lead to results that do not generalize to the population of interest. And, in fact, may be irreproducible.
Not paying attention to these details and thinking (or hoping) that standardization is always good is the "standardization fallacy". In this column, we look at how standardization can be balanced with heterogenization to avoid this thorny issue.
Voelkl, B., Würbel, H., Krzywinski, M. & Altman, N. (2021) Points of significance: Standardization fallacy. Nature Methods 18:5–6.
Graphical Abstract Design Guidelines
Clear, concise, legible and compelling.
Making a scientific graphical abstract? Refer to my practical design guidelines and redesign examples to improve organization, design and clarity of your graphical abstracts.
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An in-depth look at my process of reacting to a bad figure — how I design a poster and tell data stories.
