JTL My first thought is I'm not triggered in the same way
Fluorescent lights are my only trigger
It sounds like a general numbing procedure using lidocaine by inhalation.
Why would / does that work? Does it cause side-effects like some level of depressive action on surrounding tissues? What's being affected that makes everything suddenly feel ok? What isn't being overstimulated?
I'm glad for the OP referenced, that it worked and is able to function. But what else was affected? If it works for you as well JTL, then maybe something is not reacting as much as it would when not in a depressed state, so to speak.
But even if it does work, it really just justifies and raises further questions of "eye-strain" - rather then provide a long-term solution. Which isn't a bad thing.
Maybe the problem location can be isolated and be put in a depressed state in a more controlled fashion.. Hmm..