I've heard that if you have astigmatism light themes are beter or vica-versa. But there was a study on that topic, as far as I remember.

Interesting, I actually have astigmatism.

Your eyes evolved for seeing. They're incredibly intelligently designed for that purpose. No choice of colour, no lighting, no shapes or content will have a deleterious affect on your eyesight. You mom was wrong.

Focusing at desktop screen distance for hours at a time has never been shown to affect long-term ability to focus, despite the truthiness of what you may have read in opinion pieces on the internet. It doesn't hurt to take a break for all kinds of reasons, but avoiding eye damage is not really one of them.

Some people get eyestrain when trying to focus under certain circumstances. Eyestrain is in fact the muscles around your eyes, not your eyes themselves, and often is a result of squinting in order to (a) adjust the shape of the eye or (2) reduce the aperture into effectively alter internal focal length. Both of those should be alleviated by corrective lenses. What that generally means is you have a preexisting condition that you're trying to compensate for, not a condition caused by staring at your screen. Get your eyes tested.

It's a fact that most people's eyesight deteriorates over the years. I keep getting my bifocals strengthened, and I find I now need them to use a lot of computer screens for work (damn high-res displays, get off my lawn). Your eyesight is not the only thing that deteriorates when you hit your 50s though, and it's all been happening since long before computers screens were invented. There is no correlation between computer use and deteriorating eyesight.

TL;DR don't worry about it, you can do it as much as your want and it's not going to make you go blind.

absolutely spot on. A lazy eye /squint can get worse by excessive screen use and if you are drunk or tired it can seam like you cant focus on the screen at all otherwise there is no harm at all, your eyes and just strained.

if you get glasses and you don't need them, that is worse.

I do much less than I should, probably :)

I'm kind of amazed that so few companies (Just one) have even attempted to develop an e-ink computer display. I know that refresh rates generally suck, especially on panels that can only do full-screen refresh, but I'd go for even the equivalent of a highish-resolution e-INK text terminal -- then it could be optimized to refresh characters / lines at a higher rate. Make it a color e-INK panel (current displays do 16 shades of RGB for 4096 colors) and you've have a damn fine display for your emacs/vim/TMUX session.

As a writer and a programmer, I'd buy something like that in a heartbeat. It'd save my eyes and probably be a productivity boon too if it means my eyes are less tired throughout the day. The Dasung display I linked is only greyscale, and the refresh seems to be too slow. I'd think you'd need 24/30 FPS for a terminal to feel responsive.

24/30 FPS

24/30 FPS sounds enough for programming and reading.

About a fortnight ago, I was watching a talk on eye tracking where the speaker said that the fatigue sensation you feel is actually due to your eyelids. If you think about it, it makes sense, considering that your eyes are repeatedly moving while you're asleep.

I'm in my early 30s, but when I think of older programmers, say, twice my age, they don't seem to have horrible vision. Of course, people have a tendency to change roles in their careers, so maybe that's why.

Does looking at the keyboard while I type count as protecting my eyes from prolonged exposure to the screen?

Does looking at the keyboard while I type count as protecting my eyes from prolonged exposure to the screen?

Yes.

Also, moving your lips to sound out the words as you type helps burn excess calories, which has been associated with longer and healthier life.

f.lux is definitely worth downloading; I've found it more useful for being able to get to sleep than for the sake of my eyes, but I tend to keep the brightness low anyway.

I only ever sleep during the day, so this is never an issue for me. ;)

No choice of colour, no lighting, no shapes or content will have a deleterious affect on your eyesight. [...]

Yes, and no. I'll give you that nobody is likely going blind because of working at a computer screen, but... you may want to research "trabecular mesh" as well as "Schlemm's canal".

Mydriasis as well as focussing at infinity helps lowering intraocular pressure by keeping these maximally open. Focussing near, or with strong miosis (kinda inevitable when looking at a bright light source!), they're shut. Thus, the effects are not only just opinion pieces, there is also a bit of a physiological truth behind that.

Also, unrelated to the actual eye, a lot of people have one or the other neurological condition which reacts unfavourably to bright light, high contrasts, and extreme transitions (think e.g. migraine, or some mild forms of epilepsy).

Look at something at least 50m away for 30 seconds every 10 minutes.

I do something similar, but mine is 20-20-20 :) I also have tinted lenses when i use a computer