My buddy dBm took pity on my plight:
The far end has a 2.5 mm hex driver, although I’ve never encountered a nut for an M1×0.25 screw in the wild. It doesn’t fit an 0-80 nut and gulps 00-90 nuts, so it’s definitely hard metric.
My collection of glasses required an aggregate two turns of tightening, which prompted dBm to remind me of threadlock.
Done!
Thank you, dBm!
The Smell of Molten Projects in the Morning 
Pleased to be of service! Flattered to be mentioned in your blog!
But you’ve blown your cover! [grin]
When I traveled a lot I used to carry something like yours but just a flat screwdriver for my eye glasses – just fit the screws – had gotten tired of using the end of a knife – probably have it around somewhere
Best find it again: ya never know when you’ll need it!
Just checked and it was right in the bottom of the shaving kit along with a 6 inch scale -not my old Starrett favorite (C604RE) – the scales were so important I always had at least two spares with me just in case I dropped the main one where it could not be retrieved or someone liked it better than I did
This ensures your tiny screws will never come loose!
I’m with you!
For the longest time, a machinist’s scale lived in my belt pack, because sometimes you need a length, and, when the corners (steel FTW!) began chewing through the pack, I added heatshrink caps. Gave it up when the Pixel began living in the pack while biking: the screen makes a tempting target and, hey, the phone has an app with an on-screen scale.