Charting Visibility: Eye Chart Design

How the eye chart became iconic communication design

The eye chart, the oldest tool for measuring visual acuity, has long escaped the stolid confines of the optometrist’s exam room. Today, eye charts are everywhere. You’d have to be blind if you haven’t noticed.

We’ve welcomed them into our homes, from eye chart doormats to area rugs, wall decals, throw cushions, electric outlet covers, and window curtains.  

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Eye chart area rug (from Bev Hisey), outlet cover (from 3drose), and window curtain (from Golee)

Should a guest need to visit your bathroom, with an eye chart shower curtain, eye chart hand towels, and eye chart toilet decals, now you can ensure that their time inside will be well spent.

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Eye chart shower curtain (from Royal Lion), hand towel (from Hlinksy), and toilet decal (from The Decal Guru)

We can eat cookies imprinted with eye charts, drink whiskey out of eye chart flasks, and serve Thanksgiving dinners on porcelain eye chart plates (in case your eyes tend to be bigger than your stomach).

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Eye chart cookie cutter (from Bakerlogy on Etsy), flask (from Wild Eye), and plate (from 3drose)

Now we can even wear eye charts—from head to toe. Whether you choose eye chart earrings, eye chart cuff links, eye chart tights, eye chart flip flops, eye chart ties, eye chart pajamas, or eye chart temporary tattoos, you’ll be looking, well, sharp.

 

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Eye chart tights (from The Sockalypse), flip flops (from Cafepress), necktie (from Wild Ties)

The design’s enduring appeal

But there’s something more here than just beholding beauty in the eye chart. There’s a hipsterish statement about the enduring efficacy of an analog, more handcrafted system, aligning with hipster glasses, hand-drawn typography, and apothecary packaging styles. And there’s a utility inherent in the structure of the eye chart. Eye chart layouts and typography have been used for wedding announcements, birthday cards, political posters, and even university marketing communications.

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Eye chart greeting card (from NewtonAndTheApple on Etsy), design for Yale Alumni Fund by Paul Rand (from International Poster Gallery), political campaign paraphernalia for Rand Paul (from the Rand Paul campaign store)

It’s clear. More than just decoration, eye charts have become a distinctive form of communication design, a graphic device with a voice of its own.

A strange change

And this is a bizarre shift. After all, the eye chart was first a medical device, a tool for measuring a body condition. It’s analogous to the thermometer, the blood sugar meter, the goniometer (a tool for measuring a joint’s range of motion), and perhaps even the Brannock device (those sliding metal trays for measuring your shoe size). Sure, these tools aren’t encountered as regularly by the average person, but that can’t be the main reason for the staggering abundance of eye chart-inspired stuff.

So how did the eye chart become so visible in pop culture?

An un-standardized test

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Early eye chart by Heinrich Küchler (from School Health)

Historically, the eye chart has always taken many forms, formats, shapes, and sizes. Despite its ability to divide populations into those who legally can drive, fly aircraft, or serve on combat duty based on test results, there is no single, universal eye chart. A doctor may select from a wide variety of designs. Of course, 20/20 acuity should mean 20/20 no matter the design of the measuring chart, and eye charts for medical use are created with general specs to minimize variability in results. Even so, some research has shown statistically significant differences in acuity scores resulting from different chart designs.

The classic chart

There have been attempts to create a single, standardized chart. The first known attempt was in 1836, with German physician Heinrich Küchler cutting pictures and letters out of magazines, newspapers, and books. Most publications of the time were set in blackletter, which carries its own suite of legibility difficulties quite separate from visual acuity. Perhaps unsurprisingly, then , when Küchler published his chart with twelve rows of letters in 1843, it was not widely circulated or even republished a second time.

In 1862, Dutch ophthalmologist Herman Snellen designed the classic chart that starts with a single large letter at the top (an “E”) with rows set in decreasing size. Snellen’s chart letters were designed on a 5×5 unit grid, standardizing the width of the letters, the thickness of the letters’ lines, and the spacing between letters. The English term “optotype,” referring to letters of specific sizes used for visual acuity testing, was eventually modelled out of the German Optotypus, a term Snellen began writing in publications as late as 1875.

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The Snellen Chart (from Jeff Dahl on Wikipedia) and the 5×5 grid underlying Snellen’s optotype design (illustrated by Joe Hodapp, from ILoveTypography.com)  

Variety reigns

Lack of standardization enables variety. Which is exactly what has happened with the eye chart. Since Snellen’s chart, numerous alternatives have emerged, ranging from pictures of animals to “the tumbling E,” rotating C’s, numerals, hand iconography, and more. Some designs have attempted to minimize variability in viewing conditions, such as by installing charts with lighting panels. Others have attempted to accommodate different language capabilities, or levels of hand-eye coordination ability.

Eye chart with rotating cubes by Chas Wray, “kindergarten test chart” with animals and shapes by Wendell Reber, eye chart cabinet by Nelson M. Black with inner lighting (and, interestingly, a panel of blackletter optotypes on the side). All from The American Encyclopedia and Dictionary of Ophthalmology, ed. Casey A. Wood)

Eye chart with rotating cubes by Chas Wray, “kindergarten test chart” with animals and shapes by Wendell Reber, eye chart cabinet by Nelson M. Black with inner lighting (and, interestingly, a panel of blackletter optotypes on the side). All from The American Encyclopedia and Dictionary of Ophthalmology, ed. Casey A. Wood)

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Eye chart based on hand gestures (published by Cromelin et al. in Ophthalmology. 2012 Oct; 119(10): 2009–2013.)

Dozens of new chart designs continued to be proposed in scientific publications every year. Yet, despite the lack of official design rules (aside from having to measure visual acuity within statistically acceptable ranges, which is determined by comparing results against those from a more commonly used chart), most eye charts take on a similar format, making them instantly recognizable as a class. A vertical page, rows of graphics, black and white.

Though the Committee on Vision and International Council of Ophthalmology has published specifications on eye chart design, describing details like spacing, leading, and sizing increments, they are guidelines. The eye chart’s freedom from universal standardization paved its path to becoming a remixable graphic.

That much, at least, has become clear in hindsight.

Oh say, can you see? (The art of visual punning)

Eyesight has long-standing metaphorical significance in Western society. (Remember Oedipus Rex and King Lear?)

Even today, “vision” can refer to sight as well as imagination and foresight (“Their vision was to build a solar-powered chocolate factory.”). “Seeing” can refer to sight as well as understanding and awareness (“See?”).

And so, all along, the eye chart was a punning opportunity just waiting to be tapped.

The pun starts here

Reading an eye chart-formatted message is like assembling a 2D puzzle. The built-in visual silence surrounding each letter slows us down, forcing us to spell out the joke to ourselves. The black and white, poker-faced design gives us no clues to what we’ll discover. And maybe a human tendency towards “effort justification” makes us believe that the more effort we put into a task, the more we appreciate the outcome.

But whether it’s a candy advent calendar or an eye chart phone case, we delight in unraveling insight. We can be surprised when Catherine Zeta-Jones’ character in America’s Sweethearts begins spelling out “I LOVE YOU” during an eye exam when reading off the chart installed by her amorous optometrist.

We can separate phrases by line, adding clarity, or merge them together to simulate speed (such as “K THX BYE” at the bottom of this chart…)

OMG eye chart

Eye chart phone case (from case.grapix on eBay)

More punning possibilities

We can even rely only on the chart’s iconic format to carry off a pun. Once that structure is in place, we can apply blatantly non-optotypes for images, such as gnawed-upon donuts in place of the classic rotating C, or, to poke fun at the increasing difficulty of the chart, photos of a striptease.

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Eye chart with donut illustrations by Zachary Huang (from The Optical Vision Site) and eye chart with photos of a striptease for Art Foco Otica, a Brazilian optical clinic (from Coloribus)

Charting an icon

The eye chart has come a long way from its clinical origins. In popular culture today, the eye chart bespeaks trendiness and hipness. It can tell a joke amplified by metaphorical significance and enabled by its layout.

So, the eye chart has attained a rare status: it is a specialized medical tool, a style icon, and a communications template. How we read it now requires both sight and insight.

 

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