P R Scudder, Shiyu Zhang, Tora Sund Morken, Christiane E.L. Dammann, Olaf Dammann
AIM: To evaluate whether Retinopathy of Prematurity (ROP) research cohorts should be defined exclusively by gestational age (GA) thresholds rather than the current standard of combining GA with birth weight (BW). METHODS: Literature search of publications between 1971 and 2024, and data extraction using predefined search terms and inclusion criteria. RESULTS: ROP prevalence changes notably at around 28 weeks GA, decreasing appreciably at older gestational ages. Including BW alongside GA (as is done in some ROP screening guidelines) affects the variability of ROP prevalence data and may obscure the true population-level association between GA and ROP severity. CONCLUSION: Clinical study populations for ROP research should be defined by GA thresholds only, without additional BW inclusion criteria.