Ocular myasthenia gravis (OMG) therapy should address three issues – restoration of normal binocular vision. prevention of deterioration to generalize MG (GMG), and avoiding significant adverse effects of treatment. Prior studies suggest that moderate dose followed by low dose daily prednisone can accomplish this for at least two year. Long term issues however, have not been addressed. We hypothesize that OMG patients who had been treated or required daily low dose prednisone (< 7.5 mg daily) would maintain control of OMG and continue with a low rate of conversion to GMG.

Chart review of OMG patients managed in one Neuro-Ophthalmology service who did not develop GMG within 2 years (previously reported) with longer than 3 years follow up were evaluated. We evaluated the average daily prednisone dose, additional immunomodulatory therapies, whether diplopia in primary and downgaze remained, ocular motility exam (at the last visit), and whether GMG developed after 2 years.

106 patients (30 women, 76 men, age 56.6± 19.3) were followed for 8.4 ± 5.2 years. 87 (83%) required chronic prednisone, approximately 5.2 ± 8.4 mg daily dose.  41 (39%) had prednisone failure requiring additional therapy (azathioprine, mycophenolate, plasmapheresis, IVIG, rituximab, cyclosporine).  GMG developed in 13/106 (12.3%) of patients at average 7.7 ± 8.2 years (yearly incidence 2.4%).  At the last evaluation, 84% had no or limited diplopia or vision blocking ptosis.

Low dose prednisone remains an adequate therapy to control OMG in the majority of patients, but a significant minority have underlying medical issues or fail therapy, requiring additional immunosuppressive therapies. Conversion to GMG remains low on low dose prednisone and / or other immunosuppressive agents. Prednisone remains the main therapy for OMG but it is not a cure or ultimate panacea.