You would think monitor manufacturers would the brightness control go all the way to barely visible, but they don't. I have two monitors, an Asus and a Dell, both set to what they consider brightness level 0, and neither quite as dim as I'd like.

On most display devices, "contrast" controls the white level and "brightness" controls the black level. (These controls of course interact.)

For your use case, you might want to be adjusting contrast down.

You can get them to go lower at that point by decreasing the contrast. But yes, you highlighted what my problem with brighter displays is.

I work in a pretty bright office -- usually I have the windows open and the overhead light on. My monitors (a Planar and a Philips) are both plenty bright enough for this use case, but neither of them will get as dim as I'd prefer once it's dark out and I have only the overhead light. If I would prefer to work by lamplight only (as I sometimes do), the contrast between the super-bright-on-the-dimmest-setting monitors and all the peripheral space around them makes my eyes hurt.

And, here's the thing: I like brightness, usually. As @ianai mentions, what's needed is a larger range, not the same range but brighter.

Consider using f.lux (or a copycat on Linux) to dim and match the color temperature of your lamplight in the evening.

I have used f.lux and redshift in the past. They can help reduce the eyestrain a little, and I guess they have a psychological effect around sleep, but they don't actually dim the light.

Once upon a time it was normal to adjust the location of the desk to the person working there. If lefthander, place table towards the left wall with light coming from window on the right. If righthander, place to the right of window. The typewriter was placed on a small table in front of the window.

When the computer showed up, it was first placed in the corner toward the window or in front of the window but the later location proved hard on the eyes so we stopped with that.

What has changed now that we stopped with this practice? I thougt we would have the office layout perfected by now?

Not being a part of a hive mind unfortunately I did not have this wisdom inbuilt and apparently neither did the people designing my house with the window facing the sun that my home office lives in.

I could rotate the layout 90 degrees and only have sun glare half of the day but it's just easier to either close the curtain a bit or crank the brightness