Medical and surgical treatment for ocular myasthenia.

BACKGROUND

Approximately 50% of people with myasthenia gravis present initially with purely ocular symptoms, so called ocular myasthenia and between 50 to 60% of these people will progress to develop generalized disease. The vast majority will do so within the first one to two years. There is controversy surrounding the appropriate management of patients with ocular myasthenia.

OBJECTIVES

To perform a systematic review of the literature relevant to the treatment of ocular myasthenia and to answer three specific questions. Are there any medical or surgical treatments that have an impact on the risk of progression from ocular to generalized myasthenia gravis? Are there any medical or surgical treatments that improve symptoms of diplopia or ptosis in ocular myasthenia? What is the frequency of side effects associated with treatments used in people with ocular myasthenia?

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register (searched December 2004), MEDLINE (1996 to 2004) and EMBASE (1980 to 2004) for randomized controlled trials as well as case-control and cohort studies. The titles and abstracts of all articles were read by both authors and the full text of all articles that were of possible relevance was reviewed in full. The references of all manuscripts included in the review were scanned to identify additional articles of relevance and experts in the field were contacted to identify additional published and unpublished data. Where necessary and possible, we contacted authors for further information.

SELECTION CRITERIA

To be included in the review, studies had to meet three criteria: (a) randomized (or quasi-randomized) controlled study design; (b) active treatment compared to placebo, no treatment or some other treatment; and (c) results reported separately for patients with ocular myasthenia (grade 1) as defined by the Myasthenia Gravis Foundation of America.

DATA COLLECTION AND ANALYSIS

We collected data regarding the risk of progression to generalized myasthenia gravis, improvement in ocular symptoms, and the frequency of treatment-related side effects.

MAIN RESULTS

We identified two randomized controlled trials relevant to the treatment of ocular myasthenia, only one of which reported results in terms of the pre-specified outcome measures used in this review. This study included only three participants and was of limited methodological quality. In the absence of data from randomized controlled trials, we present a review of the available observational data.

AUTHORS' CONCLUSIONS: There are no data from randomized controlled trials on the impact of any form of treatment on the risk of progression from ocular to generalized myasthenia gravis. The available randomized controlled literature does not permit any meaningful conclusions about the efficacy of any form of treatment for ocular myasthenia. Data from several reasonably good quality observational studies suggest that corticosteroids and azathioprine may be beneficial in reducing the risk of progression to generalized myasthenia gravis.