I too have eye twitching, although not all the time. I have mostly ocular MG and am currently on 30mg Mestinon three times a day and 5mg of Prednisone every other day (working my way down from 40mg daily).

While mine is annoying, I can deal with it -- still trying to figure out the triggers or how soon before or after taking meds that it's the worst. I do have days (though few) where they don't bother me at all.

Fluorescent lights (like in grocery stores, doctor's offices, etc.) and bright sunlight also bother my eyes.