I could be misremembering this, but haven't head-mounted displays of one sort or another been used in industrial settings for something like 20 years? I don't remember when it was, but I seem to recall something with monochrome (and lower-resolution) displays like this being used in things like airplane repair[1].

[1] After a little searching, I may be remembering reading about the 1996 Boeing conference: https://www.media.mit.edu/wearables/lizzy/timeline.html, or it could be any of the other late-90s systems listed here: https://en.wikipedia.org/wiki/Optical_head-mounted_display that got press at the time.

Edit: Looking at another page, I may actually be remembering something from computer magazines back while I was in college or shortly after - the Private Eye from Reflection Technology (1989) (https://glassdevelopment.wordpress.com/2014/04/17/hmd-histor...) - which would fit, because that plus the Twiddler chorded keyboard became part of the MIT Wearable Computer stuff and I remember wanting one of those keyboards.....