Choroidal Structural and Vascular Changes During Myopia Progression and in Response to Myopia Control Interventions: A Systematic Review.

This systematic review evaluates current evidence on choroidal structural and vascular changes in myopia development and progression and assesses how these parameters are influenced by different myopia control interventions. A literature search was conducted in PubMed and Scopus for studies published between January 2000 and January 2026, following PRISMA 2020 guidelines. Eligible studies included human observational and interventional research investigating choroidal parameters, primarily choroidal thickness (CT) and choroidal vascularity index (CVI), in relation to myopia progression or treatment response, including pharmacological (atropine), optical (orthokeratology and defocus-incorporated lenses), and light-based interventions. Due to heterogeneity in study designs and outcomes, a qualitative synthesis was performed. Forty-one studies were included. Evidence from cross-sectional and longitudinal studies consistently showed reduced CT in myopic eyes, with choroidal thinning associated with axial elongation and refractive progression. Multiple interventions were associated with measurable choroidal changes, most commonly transient or sustained thickening. Optical and light-based therapies demonstrated more consistent and pronounced choroidal responses, often driven by vascular expansion, whereas atropine showed dose-dependent and variable effects. Early choroidal thickening correlated with slower axial elongation and reduced myopia progression, suggesting a predictive role. However, variability in imaging techniques, study populations, and follow-up durations limited comparability across studies. Overall, the choroid emerges as a dynamic, treatment-responsive tissue involved in myopia pathophysiology, and choroidal parameters (particularly early changes in CT and vascularity) show promise as functional and prognostic biomarkers for myopia control. Further standardized, longitudinal studies are needed to clarify underlying mechanisms and to establish the choroid's role in personalized myopia management.