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Comment by steve1977 | Hacker News Reader

steve1977

Having astigmatism, I definitely feel like text in dark mode is harder to read than dark text on light background.

In regards to eye strain with light mode, what I found important is to match screen brightness to „environmental brightness“ (don’t know the proper term).

As a rule of thumb, when I put a white paper in front of a white screen, the screen shouldn’t illuminate the paper more than the other lights in the room.

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It's the same experience for me.

I used to use dark mode every where because it was somewhat accepted that the lesser bright the better.

But then I read a science-based post years ago about why light mode is better for our eyes, especially for people with astigmatism, as our eyes are naturally used to focus on objects on bright scenarios (sunlight).

Switched back to light theme right away, except for coding, because actually syntax highlighting is better with dark background.

Bit of a long shot, but I don't suppose you'd happen to know where to find that post or what it was called?

https://www.nature.com/articles/s41598-018-28904-x

Proposes that black on white text stimulates a pattern of expression in visual system that may contribute to myopia:

> Using optical coherence tomography (OCT) in young human subjects, we found that the choroid, the heavily perfused layer behind the retina in the eye, becomes about 16 µm thinner in only one hour when subjects read black text on white background but about 10 µm thicker when they read white text from black background. Studies both in animal models and in humans have shown that thinner choroids are associated with myopia development and thicker choroids with myopia inhibition. Therefore, reading white text from a black screen or tablet may be a way to inhibit myopia, while conventional black text on white background may stimulate myopia.

Careful there you got the conclusion other way around.

You said WoB contributes to myopia.

Your own source says WoB inhibits myopia.

Damn you're right, I said it both ways around -- fixed

Doesn't your quoted passage say the opposite? Reading white text on a black screen may inhibit myopia, and black text on white background does the opposite?

Not the poster, but I've seen a couple of these which cite papers and research:

https://stitcher.io/blog/why-light-themes-are-better-accordi...

https://medium.com/codesphere-cloud/should-you-really-be-cod...

sites designed in dark mode generally need to be larger / thicker, since white text on dark background tends to "appear thinner" and disappear into the background. Lots of sites only invert colors but don't account for this weird optical illusion and don't adjust font size/weights/colors.

It's the opposite for me with astigmatism. Black text on white tends to blur or double into a grey blob, white text on black still sometimes does that, but I find it easier to parse in comparison.

> „environmental brightness“ (don’t know the proper term)

"Ambient" brightness. You were close, and that term worked well enough!

I have astigmatism and experience the opposite. Not sure why. Is it because I always wear glasses?

I'm in the same boat with corrective lenses. It would be interesting if glasses/contacts had this side effect.

Similarly. Astigmatism, glasses, and dark mode is a lot easier for me.

I also wear glasses all the time, even computer glasses.

I’m nearsighted, maybe that’s a differentiator? Although I‘m not sure if astigmatism always comes with nearsightednesd or not.

I have slight hyperopia, but it's dwarfed by the much more significant astigmatism.

I have astigmatism, and I read without glasses (by holding the device close enough to the eyes). I find black-on-white more readable in general, but red-on-black is equally readable at night.

I have astigmatism too. Dark mode is a bit blurrier, but at least I can't see my floaters.

Fair enough. I also have floaters, but not enough to be disturbing

> In regards to eye strain with light mode, what I found important is to match screen brightness to „environmental brightness“ (don’t know the proper term).

Oh yes, exactly this. At evening when sun is going down, then I can feel eye strain as I am looking into brighter and brighter monitor. Switching the light on will easily resolve it.

I second that. For me it's worse actually during times when I would normally use dark mode (i.e. evening). My 40-something eyes can get tired while having contact lenses and then dark mode is not so much helpful.

When switching to glasses it's actually bit better.

No correction glasses/contact lenses?

In my experience, these aren't perfect and symptoms of astigmatism can be aggravated by eye strain, dryness, allergies, poor lighting, etc even with correction.

So how you know that this is related to (and only to?) astigmatism?

There are vision defects that are attributed to misshapen lenses/cornea that seem to be common with astigmatism, and it's those defects that flare up under the conditions I listed in the OP.

I don't have conclusive proof, of course, but in my experience it is those symptoms that get exacerbated.

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