I am not a doctor and I only know what happened to me, and I do think it can take time for Mestinon to help with Double Vision. I also see more and more improvements for myself after being on Mestinon steadily, not just the Double Vision improvement. My opinion is that there are some long term or long lasting benefits from Mestinon, I do think it is a slight immunosuppressant (as Annie mentioned in another post). This long term effect makes a huge difference in my quality of life. I did not have all of my current improvements after a week or even a month, or even two months, although I did get over the worst of the symptoms after a few days on Mestinon.

My doctor said that Mestinon is slow to help with Double Vision, that it helps more after you have taken a steady dose for a while and I vaguely remember him saying that it may take 6 months for the DV to go away. Of course, so many doctors seem to have different things to say about things concerning MG so who knows. My improvements may have something to do with dosage.

I want to report that I have not had double vision for quite some time and am almost ready to say that my double vision is "cured" (can't think of a better word).

I would recommend to anyone with MG to try Mestinon for at least 6 months before giving up, as long as they don't have any bad side effects. Much better than the risks of steroids or immunosuppressants (except in situations when the the benefits outweight the risks). Of course, again, I am not a doctor.

I am not trying to argue, but to point out that everyone is different.