BENEFICIAL-EFFECTS OF CORTICOSTEROIDS ON OCULAR MYASTHENIA-GRAVIS

Objective: To determine if moderate- or low-dose corticosteroid therap y can reduce the diplopia and frequency of deterioration to generalize d disease in ocular myasthenia gravis. Design: Retrospective record re view. Setting: Two university-based neuro-ophthalmology services. Pati ents: All 32 patients with ocular myasthenia gravis, treated with pred nisone, followed up for a minimum of 2 years were included. Patients w ere treated with 1 or more courses of daily prednisone (highest initia l dose, 40-80 mg) gradually withdrawn over 4 to 6 weeks. Subsequently, in 6 patients, 2.5 to 20 mg of prednisone was given on alternate day. Outcome Measures: Diplopia in the primary position or downgaze diplop ia and generalized myasthenia gravis after 2 years of follow-up. Resul ts: Diplopia, which was initially found in the primary position in 29 patients and in the downgaze position in 26 patients, was absent in 21 patients at 2 years. Generalized myasthenia gravis occurred in 3 pati ents at 2 years. Elevated serum acetylcholine receptor antibody levels and abnormal electromyography findings were not predictive of worseni ng. No patient experienced a major steroid complication. Conclusions: Moderate-dose daily prednisone for 4 to 6 weeks, followed by low-dose alternate-day therapy as needed, can control the diplopia in patients with ocular myasthenia gravis. The frequency of deterioration to gener alized myasthenia gravis at 2 years may be reduced; 9.4% in this study compared with more than 40% previously reported frequency. Corticoste roids may be useful even when ocular motor dysfunction is not normaliz ed.