Therapeutic options in ocular myasthenia gravis

The term ocular myasthenia gravis refers to the disease clinically restrict ed to extrinsic ocular muscles. It can be disabling as ptosis, and to a gre ater extent diplopia, both interfere with daily activities. Although ocular disturbances are the most frequent initial complaints in myasthenic patien ts, symptoms usually progress to generalized disease and only 15% of patien ts complain of purely ocular weakness for the entire course of their illnes s. Secondary generalization occurs with the highest frequency in the first 2 years from the onset. Both the severity of symptoms and the risk of gener alization should be taken into account when devising a therapeutic plan for these patients. Anticholinesterases are of limited efficacy and a consider able proportion of patients require additional therapy. Corticosteroid ther apy, generally prednisone on an alternate-day schedule, is very effective, but a reason for concern is represented by the frequent need for longterm a dministration with increased risk of severe complications. In patients unre sponsive to prednisone or requiring too high dosages, immunosuppressive dru gs like azathioprine should be used with the same criteria applied in gener alized myasthenia. As corticosteroids and immunosuppressants reduce the cha nce of generalization, their use is justified in patients with recent-onset disabling disease. In long-standing cases with low risk of generalization, treatment is aimed at the relief of symptoms and pharmacological therapy s hould be reduced to the minimum effective dosage. The indication for thymec tomy in ocular myasthenia remains highly controversial and should be reserv ed for disabled patients in the early stages of the disease. (C) 2001 Elsev ier Science B.V. All rights reserved.