Intrastromal antimicrobial injections in microbial keratitis: Current evidence and clinical perspectives

Intrastromal antimicrobial injections are an emerging adjunctive treatment for severe, deep, or recalcitrant microbial keratitis when conventional topical or systemic therapies are insufficient. By delivering high local concentrations of antimicrobial agents directly into the corneal stroma, this approach may overcome limitations in tissue penetration and, in selected cases, delay or avoid the need for keratoplasty. Current evidence supporting intrastromal therapy is strongest in fungal keratitis, where it is increasingly used in deep stromal disease. In contrast, evidence for bacterial keratitis remains limited and is derived largely from case reports and small case series, typically in refractory or biofilm-associated infections. This review synthesizes the available literature on intrastromal antimicrobial injections, including indications, technique, efficacy, safety, and dosing considerations. A targeted literature review was performed using PubMed, Scopus, and Google Scholar. While intrastromal therapy shows promise, outcomes vary according to organism, antimicrobial selection, and study design. Further high-quality studies are needed to define optimal protocols, comparative efficacy, and long-term safety.