Kupersmith et al1 report that corticosteroid treatment for patients with ocular myasthenia gravis may significantly reduce the development of generalized myasthenia gravis at 2 years. In their article, the Figure showing the Kaplan-Meier curves of the cumulative development of ocular to generalized myasthenia gravis has some inaccuracies. The treated group should be the lower curve, as a dashed line, and the untreated group should be the upper one, as a solid line. The lower curve also seems to have some mistakes in scale: the 2 curves get closer and closer, whereas the follow-up period becomes longer than 2 years and finally 6 years according to the Figure. The longest period of follow-up was actually 16 years. If the authors extend the cumulative curves to more than 6 years, perhaps the 2 lines will meet. In that case, corticosteroid treatment would just delay the development of generalized myasthenia gravis for several years, as they comment in their last paragraph. A truly effective and safe regimen is needed for these patients,2 not thymectomy.
Wang H. Myasthenia Gravis: Generalized vs Ocular, and Children vs Adults. Arch Neurol. 2003;60(10):1491. doi:10.1001/archneur.60.10.1491-a