Protocol for systematic review and network meta-analysis of comparative effectiveness of surgical interventions for primary congenital glaucoma

Introduction Primary congenital glaucoma (PCG), a type of childhood glaucoma, is primarily treated surgically to lower intraocular pressure (IOP). Failure to intervene could result in partial, or even total, blindness. Various surgical intervention types have been proposed for PCG, though the evidence on comparative effectiveness remains limited. The current protocol is an ongoing network meta-analysis enabling comparative investigation of surgical interventions for which randomised controlled trials (RCTs) are available. Our aim is to systematically compare the efficacy of various types of surgical intervention for patients with PCG. Methods and analysis Studies of interest will assess the effects of those surgical interventions on surgery-naïve children (age <18 years) suffering PCG. RCTs regardless of language or publication date will be searched from three electronic databases (Cochrane Central Register of Controlled Trials, Embase and MEDLINE) from 4 April 2022. Two reviewers will screen, first, titles and abstracts, followed by full-text papers, for useful data that they will extract. The primary outcome measure will be the IOP-lowering effect of a given surgical intervention. The two reviewers also will assess the internal validity of studies using the relevant and domain-based risk-of-bias assessment tool. Overall evidence quality will be assessed according to the Confidence in Network Meta-Analysis approach and will be presented in summarised form with network diagrams. For enhanced visualisation of the included interventions' effects, forest plots will be constructed. Pairwise effect sizes also will be calculated based on the evidence that is available in the network. Ethics and dissemination This work will synthesise evidence obtained from published studies, and as such, no ethics review or approval will be required. A paper presenting the findings will be submitted to a peer-reviewed scientific journal for publication. PROSPERO registration number CRD42022313954.