Objective: To perform a systematic review of the relevant literature and to provide evidence-based guidelines for the medical treatment of ocular myasthenia.
Methods: Medline, EMBASE, and the Cochrane Neuromuscular Disease Group Register were searched for articles of possible relevance to the medical treatment of ocular myasthenia. The titles and abstracts of all articles, as well as the full texts of all potentially relevant manuscripts, were read by both reviewers. Experts in the field were also contacted to identify other published or unpublished literature. All articles were evaluated using predefined criteria to evaluate their methodologic quality. Data from these articles were extracted to address two questions: 1) Are there any effective treatments for symptoms of ocular myasthenia? 2) Are there any treatments that reduce the risk of progression from ocular to generalized myasthenia gravis (MG)?
Results: A single randomized controlled trial compared the efficacy of intranasal neostigmine to placebo for the treatment of ocular symptoms. Methodologic limitations of this study preclude any firm conclusions. A second randomized controlled trial compared the efficacy of corticotropin with placebo, but outcome was reported in terms of a quantification of the range of eye movements. For this reason, the results of the second study could not be used to address the issues of improvement in ocular symptoms or the risk of progression to generalized MG. This review did not identify any randomized controlled trials addressing the risk of progression to generalized MG but did identify five observational studies reporting the effects of corticosteroids on progression to generalized MG, two of which also reported the effects of azathioprine.
Recommendations: The absence of high-quality evidence means that it is not possible to make any evidence-based recommendations regarding the effects of cholinesterase inhibitors, corticosteroids, or other immunosuppressive agents with respect to improvement of ocular symptoms. There is similarly an absence of evidence regarding the effects of cholinesterase inhibitors on the risk of progression to generalized myasthenia gravis (MG). Based on data from several observational studies, corticosteroids and azathioprine are of uncertain benefit in terms of their effect on the risk of progression to generalized MG.