The earliest symptom of Myasthenia gravis is double vision accompanied by progressive drooping of the upper eyelid in one eye. These symptoms become progressively worse over a course of one year or more before the doctors even suspect Myasthenia gravis. I was able to determine that my wife had Myasthenia gravis from the early symptoms about 6 months before the doctors even suspected it. The doctors first recommended lifting the eyelid with eye surgery before they even suspected Myasthenia gravis and before any specialist in thymoma was ever recommended.
Cerebral microstrokes cause left eyelid droop while the combination of high blood pressure and diabetes medications as well as Myasthenia gravis cause right eyelid droop. Double vision accompanied by left eyelid droop without any cerebral strokes might indicate Myasthenia gravis. Of course, as double vision and eyelid drooping worsen, muscluar fatigue and collapse should begin to occur more and more frequently as Myasthenia gravis progresses.
There is one observation that may relate to which eyelid droops as an indication of Myasthenia gravis. In my wife’s case, she is left handed but only her right eye had double vision and only her right eyelid drooped. So a right-handed person may have initial symptoms of double vision and eyelid droop in the left eye only as an indication of Myasthenia gravis. This is conjecture but I find no other explanation as to which eye and eyelid might indicate Myasthenia gravis. The absence of cerebral strokes as a cause of left eyelid droop may indicate Myasthenia gravis.