COSMYC: a Core Outcome Set for MYopia clinical trials with Children and young people

BACKGROUND/AIMS: Childhood myopia is an increasing public health concern, with earlier onset, faster progression and greater severity than in previous generations, increasing the risk of sight-threatening complications in adulthood. Randomised controlled trials (RCTs) of myopia interventions report heterogeneous outcomes and may not address priorities of all stakeholders. We aimed to develop a core outcome set (COS) and recommendations for outcome measurement instruments (OMIs) for myopia intervention trials in children and young people (CYP). METHODS: Using Core Outcome Measures in Effectiveness Trials (COMET) methodology, we undertook a three-phase consensus process. Phase 1 comprised a systematic literature review, workshops with CYP and parents/caregivers, and interviews with eye care professionals (ECPs) and myopia researchers to identify candidate outcomes and OMIs. Phase 2 used a two-round Delphi process and consensus meeting involving CYP, parents/caregivers, ECPs and researchers to agree on core outcomes. Phase 3 involved literature review, content-validity assessment and stakeholder consensus to develop OMI recommendations. RESULTS: Phase 1 identified 308 verbatim outcomes from randomised trials and qualitative work, from which 21 outcomes were retained for consensus. In Phase 2, stakeholders reached consensus on 10 core outcomes: axial length, spectacle prescription, visual acuity, eye health, eye comfort/discomfort, quality of life, adherence, treatment satisfaction, ocular adverse effects and systemic adverse effects. Phase 3 produced stakeholder-informed recommendations for OMIs for each core outcome. CONCLUSION: Core Outcome Set for MYopia clinical trials with Children and young people (COSMYC) provides the first stakeholder-informed COS and OMI recommendations for paediatric myopia intervention trials. Adoption and international ratification of COSMYC may improve consistency, comparability and relevance of future myopia research.