myasthenia gravis

This is a rare autoimmune disease that causes easy fatigue of muscles throughout the body.  When muscle fatigue occurs in the eye, this creates intermittent double vision (diplopia) and droopy eyelids (ptosis), especially when tired later in the day.  The mechanism of this disorder involves the body developing antibodies to its own muscle nerve receptors. The eye muscles seem to be especially susceptible to this fatigue and this disorder is often first diagnosed at the eye doctor’s office.  More definitive diagnosis is made by a neurologist who looks for certain blood markers and performs electrical muscle stimulation tests. Primary doctors are also involved to check thyroid levels and insure the thymus gland is healthy.