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Objectives To characterise engagement across the diabetic retinopathy (DR) care continuum in the USA using a cascade-of-care framework and identify gaps contributing to preventable vision loss.Design Systematic review.Data sources From September to November 2025, with an updated search in March to April 2026 using the same eligibility criteria, we systematically searched Ovid MEDLINE and Ovid Embase supplemented by reviewing reference lists of relevant articles and opportunistic searches of the Centers for Disease Control and Prevention publications.Eligibility criteria We included English -language US-based cross-sectional, cohort and case–control studies and systematic reviews containing US-based data published between 1 January 2018 and 31 December 2025 relevant to one of the defined DR cascade stages: (1) diagnosis of diabetes, (2) adherence to DR screening, (3) diagnosis of DR, (4) adherence to DR care and (5) DR-related blindness. We included systematic reviews only to inform DR-related blindness, where primary data were limited and excluded them from other stages to avoid double-counting. Exclusion criteria included studies not relevant to one of the defined DR cascade stages and editorial, perspective or commentary pieces.Data extraction and synthesis Two reviewers independently screened studies, extracted data and assessed risk-of-bias using the Newcastle-Ottawa Scale and Risk of Bias in Systematic Reviews tool. We synthesised data narratively and organised via the DR treatment cascade framework.Results Of 14 893 studies screened, 46 met the inclusion criteria. Cascade analysis revealed substantial losses in patient engagement at three stages: (1) only 15.5%–78.7% (median 59.4%, IQR 33.9%–74.0%) of individuals with diabetes obtain biennial DR screening; (2) a substantial 54.9%–88.5% (median 70.1%, IQR 62.5%–79.3%) of individuals with DR are unaware of their diagnosis; (3) only 30.9%–62.7% (median 52.0%, IQR 40.9%–59.1%) of individuals diagnosed with DR are initially linked to care and 55.3%–77.8% (median 70.3%, IQR 59.2%–77.7%) have a lapse in DR follow-up.Conclusions This review identifies major gaps in the DR care continuum, particularly in diagnosis awareness, linkage to care and follow-up adherence. The cascade framework highlights key points of disengagement and provides a basis for prioritising future research.