People have been doing their work looking at stuff held in their hands at distances of <36" forever. They’ve been reading and writing books, scrolls, clay tablets, etc. for at least 3000 years. They’ve been looking at maps, engineering diagrams, paintings, and all sorts of other stuff for nearly as long.
Yes, it takes some amount of work for your eye muscles to focus on things that are close. Yes, the closer you focus, the more your muscles need to contract. No, I wouldn’t recommend staring at a single spot 12 inches from your face for 2 hours without moving your eyes at all. But if you look around the room from time to time, giving your eye muscles a chance to relax and reset, you’re going to be just fine looking at a computer display 2–2.5 feet from your face, or even looking at your smartphone screen at 18". (I recommend putting a window with a nice view somewhere nearby; unfortunately this isn’t always possible.)
The “resting state” for vergence and/or accommodation just tells you what your eyes do if you’re not looking at anything in particular. (For instance, when you’re in the middle of fog or it’s pitch black). There’s great variation from one person to another in the resting state of the eyes. Just because your eyes naturally return to some particular focus when you aren’t focusing on anything doesn’t mean you shouldn’t look at things that are closer.
If your eyes feel tired, or you start getting headaches, or you have trouble focusing close, or whatever, by all means move your screen to whatever distance improves your symptoms. But this thing about requiring a screen >36" from your face seems like bunk to me.
Some more useful advice:
- Make sure you blink enough. People who look at computer screens a lot tend to blink less than they would otherwise, and can get dry irritated eyes.
- Don’t make your screen too dim. Our eyes work much better when looking at bright stuff.
- Make sure your screen is positioned well, so you don’t stress your neck out.
- Don’t use your computer/smartphone/etc. too close to bedtime, or otherwise use too much lighting late at night. It’ll screw up your circadian rhythms.
- Get enough sleep. Sleep is really important for most parts of the body, restoring your brain, your immune system, your skin, etc., but it’s also important for eye health. People who are sleep deprived often suffer chronic eye irritation.
- Eat a healthy variety of food, to make sure you get the nutrients your eyes need.
