Madnurse,

It took 5 to 6 months for the mestinon to (mostly) make my double vision go away, it was a gradual process. I have generalized MG, but in the beginning the double vision was my worst symptom. We all react differently, of course, some people find that Mestinon does not completely treat their double vision, I am thankful that it did for me.

I hope this helps.