Choroidal vascularity index as a marker of health and disease: systematic review and meta-analyses.

The Choroidal Vascularity Index (CVI), derived from optical coherence tomography (OCT), has emerged as a potential biomarker for detecting vascular changes. Understanding its variability across physiological states, ocular conditions, and systemic diseases is crucial for its integration into clinical practice. We evaluated variations in CVI across different physiological states (e.g., first-trimester pregnancy), ocular conditions (e.g., age-related macular degeneration[AMD]), and systemic diseases (e.g., diabetes mellitus) compared to healthy controls. From 1210 identified articles, 63 studies (7316 participants: 4000 controls and 3316 cases) met inclusion criteria. Data covered 12 distinct conditions and physiological states. Most studies were conducted in Europe and Asia, predominantly using spectral-domain OCT machines with a low risk of bias. Increased CVI was seen in some physiological states (e.g., Valsalva maneuver, first-trimester pregnancy) and some disorders (e.g. active panuveitis, inactive thyroid eye disease). Reduced CVI was found in diabetes mellitus (both with or without diabetic retinopathy), hyperopic amblyopia, and AMD. CVI demonstrates potential as a biomarker to differentiate between physiological states and pathological conditions compared to healthy controls. These findings underscore the choroid's adaptive response to systemic and ocular challenges, highlighting CVI's relevance in understanding disease mechanisms and monitoring health.