Thanks for the suggestions.

But I have Bilateral Monocular Diplopia all the time. It starts the day with what I describe as a 2mm vertically displaced ghost. By the end of the day it can be as bad as 8mm vertically displaced and the ghost can be 90% of the real image.

The eye doctor, took the easy option. Ignored my other MG symptoms, and the fact that my DV worsens during the day, and declared it Astigmatism. When I got my new glasses, they help slightly. But by the end of the day I still have DV even with the glasses.

I have no diagnosis yet, but am experimenting with caffeine. That reduces most of my symptoms, but has least effect on my eyes.