Clinical characteristics of ocular myasthenia gravis and outcomes of secondary generalisation: a systematic review protocol

OBJECTIVE: We aim to systematically assess the clinical characteristics of ocular myasthenia gravis (OMG) and report on the proportion of patients who develop secondary generalised myasthenia gravis (SGMG). INTRODUCTION: OMG is an autoimmune neuromuscular junction disorder resulting in ptosis and diplopia. A proportion of patients with OMG develop weakness in their limbs, respiratory or bulbar muscles, that is, convert to SGMG. The proportion of patients converting to SGMG reported in the literature have been varied. We therefore aim to systematically assess the clinical characteristics of OMG and outcomes of SGMG reported in the literature to date. INCLUSION CRITERIA: Studies describing a population of adults with OMG, that is, MG with ocular symptoms and signs only, seen consecutively through a clinical service, reporting on patient characteristics and the outcome of SGMG. Studies on paediatric and congenital myasthenia gravis will be excluded. METHODS: We will conduct an electronic database search for randomised controlled trials, prospective non-randomised studies, observational studies and retrospective studies in MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Web of Science. Exploratory database search was conducted on 1 December 2021. Eligibility criteria will include quantitative and qualitative articles written in any language and containing data on OMG. Additional studies will be identified by reviewing bibliographies of retrieved articles. Two independent reviewers will screen titles and abstracts and extract data from full texts, reporting outcomes according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extraction of key characteristics will be completed using customised forms. Methodological quality will be assessed using the Joanna Briggs Institute critical appraisal forms. ETHICS AND DISSEMINATION: Ethical approval is not required for this review, as it will only include published data. Findings will be published in a peer-reviewed journal and disseminated across ophthalmic networks. PROSPERO REGISTRATION NUMBER: CRD42021285257.