Apparently light-on-dark is terrible if the person has astigmatism: the edges get very blurry and doubled. There was an article on HN about this, specifically about keynote slides. Also apparently “in Europe and Asia, astigmatism affects between 30 and 60% of adults” (says Wikipedia).
I have it too, and couldn't figure out in the past why text sometimes looks horribly blurry and sometimes doesn't. With this knowledge, I realized that dark background is likely a factor.
So I like dark mode for the OS interface because it gets out of my way then, and just plain looks better. Same in apps where I click on icons and look at images, like in image editors. For reading, dark mode is torture—both with bright white text and low-contrast dark. When sites begin to switch to the dark mode following the browser, I'll have to disable that in the browser settings or deal with bright system and app interface.
However, why I can and do code with dark themes is a mystery. I even tried to bend Emacs to use a light theme for Org-mode and a dark one otherwise (not much luck, though).
I do wish that screens in the ‘light mode’ were closer to paper in terms of eye comfort. I had an e-ink device, and it was a godsend, pure bliss—you'd think that lower contrast would make reading harder but no. Something like HN's ‘black on a bit grayish with a hint of red’ emulates the experience somewhat. Just don't make text gray, please.
In related news, I'm irked that I can't have high monitor brightness for photographic images but lower for swathes of white background under text and in Jony Ive's bright flat windows. Because, you know, photos don't tend to have flood-fill of 100% white. Maybe I'll kludge something up for the browser to amend this.
Tried a lot of dark themes. I like it better, but with an astigmatism there’s no denying that I need glasses for dark mode but not for light mode. I hate wearing my glasses (20/20 in my good eye) so I recently made a switch to light mode. Everyone calls me a psychopath but I guess that’s what I get for doing what’s right for my case?
That's true for me as well. I couldn't read the oven clock (blue on black) at just 10 feet away. Anything bright on a dark background is just a blurry radiation pattern.
The reason dark-themed terminal and coding is fine, might be the monospace fonts. They are square-ish, so there is less need to find the edges accurately. They are also eligible on very cheap, trashy screens. As a side effect, code is readable in dark themes even with astigmatism. (No source, just a wild guess)
> code is readable in dark themes even with astigmatism
It doesn't make anything by itself, the difference in brightness between text and background is. I have a severe astigmatism on one eye, HN page with smaller font size is easier to read with it than a green-on-black terminal (same Noto Mono font). Red or blue colors for text on black background are also slightly harder to read due to the perception.
>I couldn't read the oven clock (blue on black) at just 10 feet away
I have good vision: no known issues, regular eye checkups, etc. But I find it nearly impossible to read most displays that use blue LEDs. If the background is blue (eg: timex indiglo watch) then it's fine. But blue leds on some of my home theater equipment drive me insane. Even if it isn't the letters/numbers themselves and it's just a regular circular power led, I find them really hard to look at.
I first noticed the blue light issue when xmas led lights were put on trees around the holidays. Blue blurry things. Now my credit union has their sign in blue and I can’t read it.
10 years later I developed astigmatism in both eyes. Dark mode is really blurry in some settings.
The blue light thing, as I understand it, is where you first begin to notice astigmatism. The wavelength is shorter and a very slight astigmatism becomes more apparent.
Whoa. I just did a quick test with someone who has astigmatism. We switched between Dark and Light themes in Google Keep. They were pretty surprised and said the difference was noticeable, that letters blurred together more in Dark mode.
I'm asytigmatic, light on dark is fine (and what I use everywhere) as long as it isn't #fff on #000 I'm OK so lots of my setup is quite light grey on dark grey.
The thing that really makes a difference for me is screen resolution (or more accurately, pixels per inch) on a modern 27" 4K I have far far fewer issues than I had on a 1280x1024 17" LCD - part of that is improvements in brightness/contrast and the technology as well though.
I have wondered for a long time about the hype around dark themes for this reason. No eye is perfect in terms of optical quality. Specifically, the lens can be misshaped and the vitreous can have impurities that lead to refraction of light.
If we look at bright light sources the pupil is almost closed, which means all light entering propagates close to the optical axis of the eye, where lens defects are not playing a huge role.
The less intense the light source gets, the more the pupil opens and more aperture is used. That means lens defects start to become more apparent and the probability the light crosses a part with inhomogeneities in the vitreous part becomes larger.
With dark themes our pupils open more, using a bigger aperture of our eyes, which allows small aberrations like astigmatism to get pronounced. These optical aberrations can lead to double vision (cover up one eye and look at the white letters on a dark background from far), for which our brain compensates when both eyes are used.
Of course, too much light isn't the answer either.
I'm not sure that this is the sole reason why light-on-dark is bad with astigmatism: because, presumably, the article about keynote slides was including presentations given in lit rooms—and eyes famously don't adjust too fast, so I don't think the pupils would react much to dark slides in a lit room. But that's only my conjectures.
Wow, this explains so much. I use a light color scheme (think default Eclipse theme) in my editor, even during late night coding binges, because I can see the text more clearly. I also have an astigmatism. Maybe related, text rendering affects me tremendously as well, like Windows/Linux text rendering forces me to squint even when the text is normal sized; but I don't have to squint on Mac OS.
Light on dark is always a bit blurrier for dark on light, because your eyes will tend to defocus when looking at a darker scene to compensate for the overall lower amount of light. This also increases the effect of optical aberrations, so those with astigmatism and the like may be affected to the point that a lighter background becomes preferable.
I’m 34. Had 20/20 vision all my life. Until around April this year from being in lockdown and stuck at home working more due to not going out and such.
I felt like I’m getting eye strain. And difficulty focusing. I ended up with glasses 3 weeks ago for “computer vision” I can’t wear them walking around the house as it makes me feel dizzy. But in front of the computer it makes a difference.
Think I’m gonna try find a good theme and try light mode for a while.
Edit: Except the iPhone 11, cos I get better battery life based on my usage. It's 7pm now, and phone has been unplugged since 8am, based on my usage its at 79%.
I had to switch from contacts to glasses after leaving college and getting an office job. My eye doctor said staring at screens causes focusing issues.
To my knowledge, eye muscles may get sort-of ‘cramps’ where they get ‘stuck’ in the same flex configuration as they were, if you focus on the same nearby distance for hours and hours. Purportedly, it's even classified as a distinct kind of myopia (the only one that's fixable with exercise), but dunno how legit that is. What I know for certain, though, is that regular exercises that move the eyes and the focus relieve the strain a lot. Rotate the eyes, move side to side, move the focus back and forth, that sort of thing. Also focus on stuff outside the window more often.
As for contact lenses, afaik they're trash with computers because they make the eye dryer in addition to what you already get due to blinking more rarely. At least that's how it was back in the day, when I didn't last more than a month or so with contacts at computers.
I've always made it a point to stand up once an hour and walk out side for 5 minutes and come back, or go get coffee or a snack.
I started working from home in January due to the virus so my hours have gone from 10am - 6pm to 8am - 10pm. Working with lights off. Getting up less. :(
also if you have glare from LASIK or sth. There are however combinations of dark mode that are much more legible. colors and fonts and UI elements matter a lot too. Outlines and lines are perceived differently if dark. TWitter's dark mode for example is terrible
I have it too, and couldn't figure out in the past why text sometimes looks horribly blurry and sometimes doesn't. With this knowledge, I realized that dark background is likely a factor.
So I like dark mode for the OS interface because it gets out of my way then, and just plain looks better. Same in apps where I click on icons and look at images, like in image editors. For reading, dark mode is torture—both with bright white text and low-contrast dark. When sites begin to switch to the dark mode following the browser, I'll have to disable that in the browser settings or deal with bright system and app interface.
However, why I can and do code with dark themes is a mystery. I even tried to bend Emacs to use a light theme for Org-mode and a dark one otherwise (not much luck, though).
I do wish that screens in the ‘light mode’ were closer to paper in terms of eye comfort. I had an e-ink device, and it was a godsend, pure bliss—you'd think that lower contrast would make reading harder but no. Something like HN's ‘black on a bit grayish with a hint of red’ emulates the experience somewhat. Just don't make text gray, please.
In related news, I'm irked that I can't have high monitor brightness for photographic images but lower for swathes of white background under text and in Jony Ive's bright flat windows. Because, you know, photos don't tend to have flood-fill of 100% white. Maybe I'll kludge something up for the browser to amend this.