Two tips. Get back from the screen and use larger fonts: http://www.smashingmagazine.com/2011/10/07/16-pixels-body-co.... Note the bit on “vergence”.
Second, against all odds I love F.lux: http://stereopsis.com/flux/. It adjusts the color temperature of your screen based on time of day. Try it for a while and then turn it off to see the difference, especially at night.
1. Invert the colors whenever possible. Dark background, light text. Zenburn is a good color scheme for this, and you can find it for just about everything, from Vim and Emacs to Xmonad, to tons of other stuff.
2. LCD only. Not a problem these days, you don't see CRTs much anymore.
3. Don't hunch over your computer. Back straight, lean back, recline if necessary or get a standing desk, and increase the font size.
4. Look up frequently and practice refocusing on items of varying distances. Treat your eyes like muscles, work out your focusing ability.
5. Stay hydrated.
6. Eat carrots.
7. Use F.lux or Redshift.
8. More if I think of it ...
The origins of dark-on-light as "readable" are old-school monochrome computer terminals, where the resolution was so low that if you used light-on-dark, you'd see all the individual pixels - light pixels lit up, dark ones didn't. We're past that now.
My opinion on this is based on anecdotal evidence only, but my eyes feel less strained with light-on-dark, even to this day, on high res LCDs.
Everyone else, experiment for yourself. Hold all other factors equal, and try one each straight for a few weeks, see if you can feel any difference.
For OP's question... I don't think my eyes have degraded one bit, but I'm still in my 20s and I had 20/10 vision to start with.
I usually use some system to take frequent breaks, usually an egg timer set to 10-15 minute intervals.
Every couple weeks, I'll isolate each eye and practice focusing near and far. I use trigger point therapy to work on the small muscle around the eye-sockets.
In general, I practice a couple of movement and relaxation exercises - Qigong and the Alexander technique. I've been using a standing work station for last six months but been using the computer heavily since about 1990 this is just extra.
I tend not avoid categories like "bad eyes" or "need glasses". If my eyes happen to have trouble focusing, I assume the muscle are tired and need some attention. I've heard that glasses just encourage eyes to get worse. I don't know if that's true but seems plausible. I'd view the body in general as involving many nested feedback loops. I believe that people who experience "health problems" often assume that they are "broken" in fashion akin to a simple machine where they often simply need "recalibrating". Not that I won't eventually "wear out" but I'm aiming to stay functional as long as possible.
Your mileage may vary. I certainly get eye irritation if I use the computer too much or don't get light.
I do have bifocals now (the type that have a gradual transition so one doesn't look like an obvious grandpa :) ). These helped enormously in my mid 40s, took less than a day to get used to.
Other than that, my corrected vision is better than 20/20.
If I could improve to better than 20/20, I might have to start wearing glasses. What are the best glasses to give super vision?
20/20 is just an average, so it's far from "perfect vision". It's like having an IQ of 100.
- outdoor light directly on retina (?)
- lutein/zeaxanthin (raw eggs), epa/dha (seafood)
I posted this study twice before on HN. It's a really useful result because it could save u and your loved ones from having to wear glasses.
http://bjo.bmj.com/content/93/8/997
This is not the only paper citing this finding. Go through the references and you will see more.
After that, using a larger font is good (I use 16pt Inconsolata with Monokai theme for good contrast). I tried out those Gunnar computer glasses and they work pretty well (I got the clear lens ones), but I always forget to wear them.
In my personal experience the various problems started to appear only after almost 20 years of staring into display. Yet once it started, there is no good way back, only trying to slow it down.
Someone once recommended Paul McCartney's "eye yoga" YouTube video - really simple exercises that don't require windows with vertical grates or special magnetic frames.
http://www.youtube.com/watch?v=00XqvNwYMoc
PS - the most hilarious part is that the video is blurry, but the rest of my screen/browser/world is in focus, so if I do the exercises enough and suddenly his video is in focus and everything else isn't, I'm going to be pissed...
A golden advice from an eye-doctor that makes my eyes much less tired (ymmv) even though I don't strictly adhere to it: every once in a while (~30min) rest your eyes by just looking at something about 15ft away or by keeping them closed for about 1 minute. Don't necessarily try to focus on something far, just look at it.
Even identical twins have different genes.
http://www.scientificamerican.com/article.cfm?id=identical-t...