Simon, I know what you mean about the twitching of the eyes. As I said, I get that from the mestinon. However, not long ago I was not taking any mestinon and my left eye was twitching non stop for weeks and it was driving me nuts. I saw my neuro ophthalmologist and she said she could stop it by injecting botox in the muscle that was causing it or I could just wait it out. A needle in my eye did not sound very appealing so I chose to wait it out. It did finally stop about a week or so later. I've had it happen a few more times, but only for days not weeks. She did say it was due to the MG. Hope yours gets better soon.
Hugs,
Pat