Eye Care Adherence in Pediatric and Elderly: Understanding and Addressing the Challenges

: Adherence in pediatric and elderly eye care is a system outcome shaped by patient, caregiver, treatment, service design, and affordability. This narrative review synthesizes recent evidence on magnitude, determinants, and consequences of nonadherence across a representative selection of major pediatric and older adult conditions, and proposes a practice- and policy-ready agenda. Using the ABC taxonomy (initiation, implementation, and persistence) as an organizing frame, we appraise measurement methods, map phase-specific barriers, and collect effective or promising strategies at patient, clinic, and system levels. Evidence indicates that avoidable vision loss often reflects failures in initiation (e.g., delayed start or first follow-up), day-to-day implementation (technique, tolerability, routine friction), or long-term persistence (retention, affordability), with objective measures typically revealing lower adherence than self-report. Multicomponent, age-tailored bundles (relational care, regimen simplification, proactive recall, caregiver support, school- or community-linked access) are more effective and scalable than education alone when co-designed and adequately supported; digital tools show potential but require validation, usability, and equity safeguards. We also identify priorities for research (harmonized, phase-specific outcomes, validation of age- and condition-specific measures, pragmatic and hybrid effectiveness-implementation designs with economic evaluation) and for policy/system reform (quality dashboards with equity-disaggregated indicators, supportive reimbursement for coordination/counseling, and outcome-linked procurement of digital solutions). We define "effective adherence" pragmatically as adherence sufficient to achieve intended clinical outcomes for a given therapy, and outline a three-pillar roadmap (Clinical, Research, Policy/System) to embed measurement, support, and accountability into routine care. Together, these steps can translate conceptual clarity into equitable and sustainable improvements in vision and eye care outcomes.