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

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).

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.

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.

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.