Apinyawasisuk S, et al. - Among patients with seropositive acetylcholine receptor antibody (AchR Ab), researchers conducted this retrospective cohort study to assess associated factors of conversion of ocular myasthenia gravis (OMG) to generalized myasthenia gravis (GMG). During July 2009 and December 2016, 71 OMG patients with seropositive AchR Ab presented. The conversion to GMG was witnessed in 36 patients. GMG's overall incidence was 14 per 100 patient-years and the probability of conversion at 2 years was 0.37. Data reported that overall median conversion time was 4.97 year. According to the Cox proportional hazard model, risk factors were female gender, smoking history, and thymic abnormalities. Receiving immuosuppressive agents and pyridostigmine were protective factors against conversion to GMG. Findings suggested that OMG patients with AchR Ab seropositive should be advised that conversion to GMG may be prevented by taking pyridostigmine and/or immunosuppressive agents as well as the cessation of smoking.