Methodology for preventing Botulinum toxin-A eyelid ptosis: Risk index derivation, safety rules, and evidence-graded management algorithm

Eyelid ptosis after cosmetic use of Botulinum toxin A, though uncommon, can impair function and patient satisfaction. We aimed to develop a methodological framework that standardizes prevention and management via a derivation-based risk index, explicit safety rules, and an evidence-graded, onset-anchored treatment algorithm. We conducted a structured scoping approach to map existing evidence and anatomical insights, then used consensus-style item generation to derive a practical risk index and codify ten safety rules. Treatments were organized into an onset-anchored algorithm with indicative effect windows and contraindications. The framework introduces a Levator Diffusion Risk Index combining anatomical, technical, and patient factors; a codified ten-rule injection protocol specifying distances, depths, dilution, and needle orientation; and a graded management algorithm for symptomatic ptosis. A standardized, reproducible methodology - risk stratification, measurable technique rules, and a graded treatment pathway - can reduce complication rates and harmonize reporting and care.