Effects of myopia control interventions on myopia progression and strabismus-related outcomes in children with intermittent exotropia: a systematic review and meta-analysis protocol

Abstract: Intermittent exotropia frequently coexists with childhood myopia. Myopia-control interventions may affect accommodation, convergence or binocular function but evidence specific to children with intermittent exotropia has not been synthesised. This review will assess efficacy in randomised trials and comparative effectiveness and safety in non-randomised studies considering both myopia progression and strabismus-related outcomes.

Methods and analysis: This protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 statement. We will search PubMed, Embase (Elsevier), Web of Science Core Collection, the Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, Wanfang Data and VIP Database together with ClinicalTrials.gov and the Chinese Clinical Trial Registry from inception to the final search date. The final searches are planned for May 2027. Eligible reports will include randomised trials and non-randomised comparative studies of participants aged 18 years or younger with intermittent exotropia and myopia. Interventions will include low-concentration atropine, orthokeratology, myopia-control spectacle lenses, repeated low-level red-light therapy and relevant combination regimens. Primary outcomes are changes in spherical equivalent refraction, axial length and distance and near angles of deviation. Two reviewers will independently select studies, extract data and assess risk of bias using RoB 2 for randomised trials and Risk Of Bias In Non-randomized Studies- of Interventions (ROBINS-I) for non-randomised studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used to assess certainty of evidence. Meta-analysis will be restricted to studies with comparable intervention technologies, study designs, comparators, outcome definitions and follow-up periods; otherwise, findings will be synthesised narratively.