Plant-Derived Bioactives in Ocular Drug Delivery: A Critical Evidence Map of Formulation Roles, Material Participation, and Therapeutic Attribution

Background/Objectives: Better ocular delivery does not establish that a plant-derived bioactive functions as a material or adds a material-specific therapeutic benefit. Methods: A structured critical synthesis of seven databases mapped 327 eligible full-text records using parallel role, material-participation, bioactivity, comparison and interaction codes. Independent full-text reassessment and human adjudication were followed by sensitivity analysis in 313 report-family units. Results: External cargo accounted for 237 records (72.5%); delivery modulators, active/co-functional interfaces and structural/self-assembling participants accounted for 27 (8.3%), 29 (8.9%) and 34 (10.4%), respectively. Practical-formulation comparisons occurred in 234 records, whereas 35 included attribution-oriented comparisons. Three records reported model-based interaction analyses, with limitations that prevented unrestricted claims of ocular synergy. Family-sensitive analysis preserved the principal patterns. The synthesis distinguished released-drug exposure from retained-interface function and aligned dry-eye, infection and corneal-repair claims with their measured models, endpoints and controls. Conclusions: This corpus more often evaluates delivery performance than an isolated material-specific contribution. Added complexity should address a defined treatment limitation, demonstrate the claimed increment against a credible comparator and remain compatible with product use. The framework guides claim-matched experiments rather than ranking platforms or predicting clinical success.