Dark mode gets sold as an eye-strain cure fairly often, usually in the same breath as battery savings and blue light. Those are three separate claims, backed by three different bodies of evidence, and conflating them is where most of the confusion comes from. Here’s what the actual research says about each one, including the tradeoffs nobody puts in the marketing copy.
The eye strain study
Researchers at Walailak University in Thailand ran a crossover experiment with 30 women in their early twenties, all with 20/20 vision and years of daily tablet use, published in April 2025. Each participant used a tablet in both light mode and dark mode, in separate one-hour sessions split between reading and a game, with fatigue measured before and after each session in three ways: a subjective visual fatigue score, critical flicker frequency (an objective test where a flickering light is slowed until it looks solid, used as a physical marker of eye fatigue), and a dry eye symptom score.
On the subjective fatigue score, there was no meaningful difference between light and dark mode. People’s reported fatigue went up by a similar amount in both. That result alone would support the “dark mode doesn’t really do anything” take.
But on the two more objective measures, dark mode did come out ahead. Critical flicker frequency dropped less after dark mode use than after light mode use, and dry eye symptoms rose less too. Both differences were statistically significant. Neither difference was large.
Here’s the part worth sitting with: fatigue went up in both modes, significantly, compared to before the session started. An hour of tablet use tired people’s eyes out regardless of which mode they used. Dark mode didn’t prevent that. It just came out slightly ahead on two of three ways the researchers measured it.
The participants were 30 women, aged 18 to 25, with normal vision and no astigmatism, myopia, hyperopia, or color blindness. That’s a narrow, specific group, and the researchers didn’t claim otherwise. A tired 45-year-old developer working a 10-hour day with mild astigmatism is a different situation entirely, and this study has nothing to say about that case directly.
Dark mode and “night mode” are not the same feature
A lot of the confusion around dark mode comes from mixing it up with a different feature entirely: night mode, sometimes called Night Shift or a blue light filter, which shifts your screen’s color temperature toward warm amber and orange tones. Dark mode changes which colors your interface uses. Night mode changes the color temperature of whatever’s already on screen. A device can run either one independently of the other.
The American Academy of Ophthalmology’s own position on this is more measured than most consumer advice: blue light itself does not damage your eyes. Their clinical spokesperson has been direct about it, framing the real concern as sleep disruption from screen use before bed, not tissue damage from blue wavelengths specifically. They still recommend night mode, but for a more limited reason than “protects your eyes”: lower brightness and reduced glare make screens more comfortable to look at, and shifting light exposure before bed helps sleep quality. That’s a real, worthwhile benefit. It’s just a different claim than the one usually attached to dark mode.
Who astigmatism changes this for
Astigmatism specifically changes the picture for dark mode itself, separate from the night mode question. Bright text on a fully black background can produce a real visual effect called halation, where light appears to bleed or glow around the edges of each letter, for people whose corneas aren’t perfectly spherical. Astigmatism is common enough that a meaningful share of any given audience has it in some degree, and for that group, aggressive dark mode implementations can make reading harder, not easier.
Halation gets worse the closer a dark theme gets to pure black background and pure white text. It’s a fixable problem: a dark gray background instead of true black, and an off-white rather than stark-white text color, reduce the contrast spike that causes the glow in the first place, while still reading as unmistakably dark mode.
The battery claim is real, but conditional
Dark mode’s battery reputation comes from OLED displays specifically, where each pixel produces its own light and a black pixel is actually switched off rather than dimmed. Purdue researchers built a dedicated power-measurement tool and tested six popular apps across four OLED Android phones to quantify this properly rather than estimate it. At full screen brightness, dark mode saved 39 to 47 percent battery on average. At the 30 to 50 percent brightness range most people actually use indoors, the saving dropped to 3 to 9 percent, small enough that the researchers noted most users wouldn’t consciously notice it.
Two things about this are easy to miss. First, it’s an OLED-specific effect: on an LCD screen, the backlight stays on at a fixed level regardless of what color is on screen, so dark mode offers no meaningful battery benefit there and can occasionally cost slightly more. Second, the battery benefit scales with how close to true black the theme actually is. A pure #000000 background saves more power than a dark gray one, on OLED, at high brightness. That’s the exact same design choice that makes halation worse for astigmatic users, pointing in opposite directions for two different real benefits.
The design tradeoff, made explicit
Mawu Dark Mode’s own default theme uses #1f222c as its background, a dark blue-gray, not #000000, and #c1c4d1 for text, a soft light gray rather than pure white. That’s a real, deliberate tradeoff, not a free win: it very likely gives up some of the battery savings a pure-black theme would deliver on an OLED laptop screen, in exchange for being readable for the share of users who’d otherwise deal with halation. For an admin dashboard that isn’t usually the main thing draining a device’s battery in the first place, that trade reads as the right one. It’s still a trade, and worth naming as one rather than claiming both benefits at once.
Put together: dark mode gives a small, real edge on two objective eye-strain measures, doesn’t prevent fatigue from building up over a long session, has a genuine but brightness-dependent battery benefit that’s specific to OLED screens, and isn’t the same feature as the blue-light-reducing night mode it usually gets bundled with in marketing. See Mawu’s 13 themes for what that actually looks like across different palettes, or Mawu Dark Mode to try one on your own dashboard.