Incidence, Epidemiology, and Transformation of Ocular Myasthenia Gravis: A Population-Based Study

A population-based study was conducted to determine the incidence and risk factors for transformation from ocular myasthenia gravis (OMG) to generalized myasthenia gravis (GMG). The study included 65 patients diagnosed with myasthenia gravis (MG) between 1990 and 2017. The overall incidence of MG was 2.20 per 100,000 per year, with an incidence of OMG at 1.13 per 100,000 per year. Of the patients with OMG, 55% converted to GMG at some point during their disease course. Factors such as positive AchR antibody and abnormal single-fiber electromyography (sfEMG) results at the time of diagnosis increased the risk of conversion to GMG. These findings challenge the belief that conversion to GMG rarely occurs after 2 years and provide valuable insights into the epidemiology and transformation of OMG.