Apinyawasisuk S, et al. - Among patients with seropositive acetylcholine receptor antibody (AchR Ab), researchers conducted this retrospective cohort study to assess the 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. Data reported that 36 patients experienced conversion to GMG. Overall GMG incidence was 14 per 100 patient-years and the probability of conversion at 2 years was 0.37. According to the Cox proportional hazard model, female gender, smoking history, and thymic abnormalities were risk factors. Receiving immunosuppressive agents and pyridostigmine were protective factors against conversion to GMG. 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 a cessation of smoking.