Peering into the accessibility of Dark Mode
An emerging trend in user interface design, Dark Mode’s USP seems to be its sustainability and easing the visual strain on our eyes. But how true are these notions — and how does it fare in terms of accessibility?
These days, Human-Computer Interaction (HCI) demands that we optimise the experience between the user and the interface to the best of our knowledge and capabilities. To achieve a challenging, but balanced grounding, it needs to be both intuitive and aesthetic.
Our definition of the latter is a constantly evolving term, and I’m sure the newest hype hasn’t escaped your attention: Dark Mode!
Please enjoy this sneak peek into your eye and its preferences. Starting right off with why protecting your vision is increasingly important in the age of screen overload.
Setting the scene & crunching numbers
A 2020 research by Lenstore has shown that our screen time increased during the pandemic, on average by 10–20 minutes depending on the country observed.
Based on their findings, the UK was at the bottom of the chart in terms of screen time usage with 5.38 hours spent looking at screens. This should seem quite a lot. But hey, it gets worse. The Philippines data showed a whopping 10 hours of screen glare per day.
If we look at 2022 behaviours in the online sphere, according to DataReportal, the average user spends almost 7 hours per day on the internet, on a worldwide scale.
(But if we look specifically at the two example countries mentioned above, the numbers show 10.27 hours in the Philippines and 6.12 hours in the UK.)
Note that screen time and internet usage aren’t always the same. For a case in point, see the below breakdown on media intake.
The author also adds for context that if you sleep for approximately 7–8 hours, that means you are spending over 40% of your waking life online.
You may (or hopefully, may not) find this a numerical snooze-fest, but I bet your eyes don’t.
Digital eye strain (DES), also known as computer vision syndrome, is an actual medical term coined by the American Optometric Association. When, in a 2020 study they looked at device-related eye fatigue, well, the results were gloomy, but expected.
As they conclude,
“the DES [digital eye strain] scores were proportional to the increase in the number of hours of gadget usage during the pandemic.”
In case you are feeling ready to throw up your hands in despair and opt for a Netflix binge to paradoxically cure the anxiety around this topic… well, do that later.
We need to talk about Dark Mode (for real) now.
How did we get here?
Especially as we are becoming more tech-savvy, we feel entitled to having our say in how the product (literally) at our fingertips is made. In other words, being able to customise our own interaction.
Thus, from a UX point of view, handing over carefully curated segments of decision-making to the user is part of creating an ideal user experience.
This is how the coveted Dark Mode got integrated with the speed and contagion of the latest TikTok dance.
Initially, it was only used by the eternally screen-bound, such as developers and other IT professionals. However, light-on-dark colour schemes soon became popular with a more casual audience, as well.
Hop on the hype train
According to Google Trends, the searches for “dark mode” had their first spike at the beginning of March 2019, and then a larger surge happened around the middle of October 2019.
Unsurprisingly, this was the year Apple released a user interface update, introducing Black Mode. Since it came from digital royalty/trendsetters, no wonder it received such traction.
Hello Darkness, my old friend
The unofficial plugins and themes marked so much customer demand, that eventually tech companies started releasing updates that made Dark Mode an optional theme. These are still being rolled out, because it has now become another feature users have come to expect.
I am Team Dark Mode myself, but the more I kept encouraging friends and co-workers to adapt to the new almighty digital trend that spares their eyes, the more I started to check in with myself.
I wondered if I wasn’t just an echo chamber, basing my assumptions on the circulated common knowledge of the wise web, and what seemed “logical.”
And since you’ve made it this far, I am guessing you might be in a similar place of questioning.
Aiming to assist with that, I’ve scoured through research papers and my own funky working theory as a baseline (biological psychology sometimes comes in handy) to dissolve the jargon into clear answers for you. Let’s get cracking.
Contrast is what helps with readability
If we go back to as far as 1987, there are findings by Carol Bergfeld Mills and Linda J. Weldon showing that people perform with a 26% better accuracy at reading text in dark characters on a light background. This is what we refer to as positive contrast polarity.
This research also added that this applies when the screen’s refresh rate is fairly high, but light characters on a dark background (i.e. negative contrast polarity) are easier to read with slower refresh rates.
More recently, the results of a 2020 study indicated that dark mode reduced visual fatigue and increased acuity in dimmed virtual environments.
Either way, high luminance contrast seemed to be the key to better performance, regardless of the applied colours.
A short biology detour
Allow me to bring some basic and simplified biology into the mix.
There are two types of photoreceptors that form the basis of your vision: rods and cones. (Well, three, if you want to start a fight on Google by mentioning intrinsically photosensitive retinal ganglion cells. Anyway, moving on!)
Rods are responsible for vision at low light levels, and they help you adapt to darkness. Cones are used for colour vision. When all cones are stimulated equally, your brain produces a sensation of white.
Once light passes through your lens (that thing behind the pupil), it focuses your eye and sharpens your vision.
In a White Mode context, this would mean that once your eye realises you are staring at a white background, it will increase its focus and see the contrasting dark text more clearly.
But when looking at a bright display, your retina’s light-sensing cells can become overstimulated, causing damage. To prevent this, your eye’s iris (i.e. its defence system against bright light) constricts the pupil in order to protect your retina, and helping you process the incoming visual stimuli better.
In Dark Mode, the white characters on the dark background have to be extremely bright if you are not in a pitch-black environment. In low light, your iris dilates the pupil to hog all the light it can find, helping you see.
Accessibility for visually impaired users
Current research seems to have a preference for casting its gaze more often on those with normal eyesight rather than those with impaired vision.
Nonetheless, below are some cases, which have been investigated.
➤ Astigmatism + Dark Mode
About one in three people have astigmatism, a condition which can cause one’s vision to be blurry at all distances.
It greatly affects night vision, because astigmatism is a refractive error, meaning the shape of the eye doesn’t focus light properly.
Since it can be problematic in dimly lit conditions, Dark Mode is probably not the most helpful in these cases, as users could find sharpening their vision, and seeing altogether, difficult.
➤ Cloudy ocular media + Dark Mode
A 1985 study by Gordon Legge and his colleagues did confirm that users with cloudy ocular media (or cataracts) did succeed better at reading in dark mode.
However, this was based on a sample size of 7 individuals, which is not enough to draw steady conclusions from.
➤ “Photophobia” + Dark Mode
Migraines can be triggered by extreme light sensitivity. According to the American Migraine Foundation, blue light is usually the most painful hue, and this is the type most commonly emitted by device screens.
In this case, Dark Mode is your friend. Users who suffer from abnormal light sensitivity disorders can greatly benefit from this feature.
Productivity myths
Whether you use Light or Dark Mode is more of an expression of identity rather than one rooted in productivity outcomes, as so far there is no evidence to support this claim.
Research by Wang and colleagues states that dark text on white background is more appropriate for everyday tasks, and for reading or writing over lengthier periods. This apparently allows humans to process the written word faster.
10 years later a further study confirmed that light polarity interfaces improved accuracy and performance. Notably, they recommended sticking to black text on white background for all ages, as study participants read faster and spotted more errors under this condition.
Is it truly more sustainable?
Saving battery life via lower energy consumption is a very timely selling point.
The supposed caveat here is that it is only true in the case of current OLED (Organic Light Emitting Diodes) screens and future devices with similar display technology, as per a 2016 study.
This is due to the black areas of the screen consuming no energy and the dimmed areas consuming less, extending the battery life of devices. Given the number of gadgets we use, this all adds up to a significant impact.
Whilst this may be true, note that even just dimming the brightness on your smartphone also improves battery life.
Decision-making comes with responsibility
You might be wondering what’s the best course of action for you or your users then.
In terms of your own user behaviour, it’s clearly up to you. Now you know the trade-offs and what the white/dark mode situation entails, so hopefully I’ve done my job serving you enough facts that will allow you to make an informed decision for yourself.
As for your users; it’s a similar story, isn’t it? People love being in charge, so it’s probably in the best interests of user experience that you incorporate both options and let them choose as they deem fit.
And if at some point down the line we will have solid research advising us to opt for one over the other based on piles of data, I’ll be covering that, too.
Notes
- Google Trends: For clarification, borrowing from Google’s own explanation, ‘interest over time’ refers to “search interest relative to the highest point on the chart for the given region and time. A value of 100 is the peak popularity for the term. A value of 50 means that the term is half as popular. A score of 0 means that there was not enough data for this term.”
Thanks for reading! ❤️
If you liked this post, follow me on Medium for more!
Further Reading
- Color blindness: how to design an accessible user interface by Ivan Tuchkov
- Accessibility vs Design trends by Michal Malewicz
References & Credits
- Dark Mode Can Improve Text Readability — But Not for Everyone by Bureau of Internet Accessibility
- Dark Mode vs. Light Mode: Which Is Better? by Raluca Budiu
- Is dark mode better or worse for your eyes? by Autumn Sprabary
- Digital 2022: Time Spent Using Connected Tech Continues to Rise by Simon Kemp
- Deguang L., Bing G., Yan S., Junke L., Yanhui H. (2016). Making Image More Energy Efficient for OLED Smart Devices. Mobile Information Systems, 2016, 1–8. https://doi.org/10.1155/2016/6575931
- Eisfeld, H., & Kristallovich, F. (2020). The rise of dark mode: A qualitative study of an emerging user interface design trend.
- A. Erickson, K. Kim, G. Bruder and G. F. Welch, “Effects of Dark Mode Graphics on Visual Acuity and Fatigue with Virtual Reality Head-Mounted Displays,” 2020 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2020, pp. 434–442, https://doi.org/10.1109/VR46266.2020.00064
- Kim, K., Erickson, A., Lambert, A., Bruder, G., & Welch, G. (2019, October). Effects of dark mode on visual fatigue and acuity in optical see-through head-mounted displays. In Symposium on spatial user interaction (pp. 1–9).
- Legge, G. E., Rubin, G. S., Pelli, D. G., & Schleske, M. M. (1985). Psychophysics of reading — II. Low vision. Vision research, 25(2), 253–265.
- Mills, C. B., & Weldon, L. J. (1987). Reading text from computer screens. ACM Computing Surveys (CSUR), 19(4), 329–357.
- Pedersen, L.A., Einarsson, S.S., Rikheim, F.A., Sandnes, F.E. (2020). User Interfaces in Dark Mode During Daytime — Improved Productivity or Just Cool-Looking?. In: Antona, M., Stephanidis, C. (eds) Universal Access in Human-Computer Interaction. Design Approaches and Supporting Technologies. HCII 2020. Lecture Notes in Computer Science(), vol 12188. Springer, Cham. https://doi.org/10.1007/978-3-030-49282-3_13
- Piepenbrock, C., Mayr, S., Mund, I., & Buchner, A. (2013). Positive display polarity is advantageous for both younger and older adults. Ergonomics, 56(7), 1116–1124. https://doi.org/10.1080/00140139.2013.790485
- Pratyusha Ganne, Shaista Najeeb, Ganne Chaitanya, Aditya Sharma & Nagesha C Krishnappa (2021) Digital Eye Strain Epidemic amid COVID-19 Pandemic — A Cross-sectional Survey, Ophthalmic Epidemiology, 28:4, 285–292, https://doi.org/10.1080/09286586.2020.1862243
- Wang, A. H., Fang, J. J., & Chen, C. H. (2003). Effects of VDT leading-display design on visual performance of users in handling static and dynamic display information dual-tasks. International journal of industrial ergonomics, 32(2), 93–104.
