Yes they do. Muscle weakness in just one eye is very common. So is weakness in the neck, in particular, and other voluntary muscles of the arms, legs and torso. Don't delay. Find a neurologist and get the simple blood test for MG. If you have to wait months for a neurology appointment, any regular doctor can, in the meantime, prescribe the test. The good news is that there are really good and inexpensive drugs that will quickly help control MG symptoms.