Within- and between-country variation in gestational age thresholds for retinopathy of prematurity screening in Latin America

Background/objectives Most Latin American countries have national retinopathy of prematurity (ROP) screening guidelines, but how consistently these thresholds are applied and whether the metric used affects cross-country comparability is poorly documented.Subjects/methods We analysed data from the SPROP (Sociedad Panamericana de Retinopatía del Prematuro) database (2021-2024), including 333 of 343 registrants from 17 countries who provided gestational age (GA) and/or birth weight (BW) screening cutoffs. We assessed between- and within-country variation, guideline concordance, and relative variability of GA and BW thresholds using the coefficient of variation (CV). Hospital-level alignment was classified as wider, at, or narrower than the national guideline.Results BW cutoffs were 3.6 to 5.1 times more variable than GA cutoffs across all countries. Mean GA cutoffs approximated national guidelines, but with marked country-level differences: Argentina applied broader cutoffs than recommended (Δ = +1.5 weeks; 50.5% permissive), Colombia and Peru applied narrower cutoffs (Δ = -1.9 and - 1.3 weeks; 62.7% and 45.5% restrictive, respectively). Mexico showed a mixed pattern (63.9% at guideline), and Paraguay had the highest adherence (80.0%). Overall deviation from guideline recommendations (permissive plus restrictive) ranged from 20.0% in Paraguay to 66.3% in Argentina.Conclusions Variation in concordance with national ROP screening guidelines reflects differences in programme implementation as well as national recommendations. Organisational stewardship, coordinated implementation, and transparent institutional policies may support effective screening, while robust local outcome surveillance is essential to guide evidence-based adaptation and future refinement of screening criteria.