Treatment of pure ocular myasthenia: A proposal from Japan MG registry 2012

Autoimmune myasthenia gravis (MG), affecting both ocular and generalized muscles, results in various symptoms. Ocular myasthenia (OM) is a form of MG that is clinically restricted to extrinsic ocular muscles. Clinical signs of OM can be highly variable, ranging from mild unilateral ptosis to complete opthalmoplegia. There is no clear evidence supporting corticosteroid use for OM. We studied 123 patients whose symptoms were limited to ocular muscles with duration of illness ≥ 2 years. We classified them into two groups: 36 patients with ptosis alone (the ptosis group) and 87 with diplopia with or without ptosis (the diplopia group). Prednisolone (PSL) and immunosuppressants were less frequently used in the ptosis group. There were no significant differences in the post-treatment condition and quality-of-life (QOL) impairment between the two groups. Forty-seven (38%) patients who failed to gain minimal manifestation or better status with PSL ≤ 5 mg/day (the unfavorable condition) showed severe QOL impairment. Ocular-QMG score was a factor associated with the unfavorable condition. A treatment strategy, discriminated by ptosis or diplopia, is necessary to improve the ocular symptoms and QOL in OM patients with the unfavorable condition.