To report the results of strabismus surgery in five patients diagnosed with myasthenia gravis with strabismus.

The authors retrospectively analyzed the effect and timing of surgery for patients who developed strabismus after being diagnosed for myasthenia gravis. Cases 1 and 2 were female myasthenia gravis patients, eight and 45 years of age, who underwent surgery after symptoms developed for correction of exotropia at 33 months and ten years after diagnosis, respectively. Case 3 was a 33-year-old male hyperthyroidism patient who had an exotropia operation six years after his strabismus diagnosis. Cases 4 and 5 were a 22-year-old female and a 50-year-old male patient, who underwent surgery for correction of left hypotropia at 14 months and ten months after diagnosis, respectively. Eventually, a total of three cases of horizontal deviation and two cases of vertical deviation had successful outcomes resulting within ten prism diopters. The patients in cases 4 and 5, both of whom had vertical deviations, experienced a short wait time from the date of symptom presentation until they were able to receive surgery. In particular, case 5 developed left hypertropia two months prior to surgery and the strabismus angle increased until six months prior to surgery. However, the hypertropia stabilized afterwards and the patient finally obtained orthophoria after a left inferior rectus advancement operation.

In patients diagnosed with myasthenia gravis and a large angle strabismus, a longer follow-up period from diagnosis to operation is necessary for a successful postoperative outcome and stable strabismus angle.