Quality of life in purely ocular myasthenia in Japan

BACKGROUND: Since there has been no conclusive evidence regarding the treatment of ocular myasthenia, treatment guidelines were recently issued by the European Federation of Neurological Societies/European Neurological Society (EFNS/ENS). However, the therapeutic outcomes concerning the quality-of-life (QOL) of patients with ocular myasthenia are not yet fully understood. METHODS: We investigated the therapeutic outcomes of patients with purely ocular myasthenia in a multicenter cross-sectional survey in Japan. To evaluate the severity of ocular symptoms, we used the ocular-quantitative MG (QMG) score advocated by Myasthenia Gravis Foundation of America. We used the Japanese translated version of the MG-QOL15, a self-appraised scoring system. RESULTS: Of 607 myasthenia gravis (MG) patients with an observation-duration of illness ≥ 2 years, the cases of 123 patients (20%) were limited to ocular muscles (purely ocular myasthenia). During the entire clinical course, 81 patients experienced both ptosis and diplopia, 36 had ptosis alone, and six had diplopia alone. Acetyl-cholinesterase inhibitors and prednisolone were used in 98 and 52 patients, respectively. Treatment improved ocular symptoms, with the mean reduction in ocular-QMG score of 2.3 ± 1.8 points. However, 47 patients (38%) failed to gain minimal manifestation or a better status. Patients with unfavorable outcomes also self-reported severe QOL impairment. Multivariate analyses showed that the pretreatment ocular-QMG score was associated with unfavorable outcomes, but not associated with the patient’s QOL. CONCLUSION: A treatment strategy designed in accord with a patient's ocular presentation must be considered in order to improve ocular symptoms and the patient's QOL.