I have myasthenia gravis. For many years I had double vision as a result (plus physical weakness when I did any repetitive movement), so I know how tiring it is to have double vision. I sympathise. MG is easy to diagnose through a blood test. I’ve been on Mestinon (nothing else) for decades, and it’s really the only long term effective treatment for MG that I know of. It had no side effects for me. I wish you good health in the future.