Probably the best choice here, if your insurance allows, is to get to a neuromuscular/MG specialist. You will generally find them at large teaching hospitals. You may need a referral from your neuro-opthalmologist, as these specialists are often hard to get an appointment with.

My thought is that you try to set up an appointment with the neuromuscular/MG specialist on your own - which may be a wait of several weeks or even months, so that you have it in place in the event that the neuro-opthalmologist's findings are still inconclusive (decreases your wait time).

If you need recommendations for a specialist, just ask the people in the forum if they know of one in your area of the country.