> Place the top of the monitor at eye level

After years of doing this, I've come to change my opinion about this. I put the monitors so I see the middle of the screen. It means that my eyes are moving in every direction, and I'm less likely to bend my neck downwards, resulting in neck strain.

EDIT: This does result in the monitor being very high up off the desk, but a good monitor arm will handle it without a problem.

If you work in GUIs a lot, your menus and stuff are at the top of the screen, and you can keep the top of the monitor eye level.

If you're a programmer and you use a fullscreen terminal, with the line you type on the bottom, your monitor needs to be higher.

What I really want is a terminal that puts the prompt at the top, aka in reverse order to what most terminals are doing today.

Put a mirror on top of your monitor so you can easily focus 20 feet away, and to see what's going on behind you

All of the above.

Also, if you wear glasses, check your prescription. A while ago, I switched to what in the UK are called Occupational lenses. The bottom of the frame is for close-up (less than 30cm) and the upper half is objects that are about an arms length away - my screen position. This helped me sit further back from my monitor but still have good visibility. Before changing, the position where I could see the screen the best wasn't ergonomically good and if I sat with good posture I couldn't see fine detail so well. It only took a few days to get used to the vari-focus.

If you go from, say, a 2K 23" monitor to a 4K 46" monitor, you want to be at the same distance to see the same pixel density, and just have more monitor real-estate subtending a larger slice of your vision.

You don't sit farther back if you install a second monitor; why would you do that if you obtain more size in a single unit?

Echoing this: periodically focusing on a distant object seems to help my eyestrain substantially.

For #2, get a monitor arm that lets you readjust the height of the monitor, especially if you regularly alternate between sitting and standing. The mono price one is good value for money here.

> 3) THE BIGGEST: The 20/20/20 rule. Every 20 minutes, look at an object 20 feet (6m) for 20 seconds.

What is this suggestion based on?

Doing research of my own on the subject. Just google "20/20/20/ rule". I just did, and found the following article. An eye care professional tracked it down and attributed to... another eye care professional.

https://www.optometrytimes.com/view/deconstructing-20-20-20-...

You can also use reading glasses if you're perpetually too close.

> Don't sit too close to your monitor(s). They should be as far away as they are big, so if it's a 23" monitor, at least 23" away from your eyes.

So if I have two monitors side by side I can have them a lot closer than if I had one ultrawide monitor?

For an ultrawide monitor, pretend it's not ultra-wide. Based on how tall it is, what would it's non-ultra wide size be? 24" Then use that.