Rose Bengal-Assisted Photodynamic Antimicrobial Therapy for Keratitis.

Rose bengal-assisted green light photodynamic antimicrobial therapy (RB-PDAT) is a new approach being evaluated for treating infectious keratitis. Preliminary clinical evidence suggests the broad-spectrum antimicrobial activity of RB-PDAT. The therapy potentially exerts its activity by generating reactive oxygen species that inhibit microbial growth. Large clinical trials are underway to further establish a role for RB-PDAT in clinical medicine, especially recalcitrant fungal keratitis that is less responsive to conventional photodynamic therapy with riboflavin. A potential limitation of the therapy includes poor penetration of rose bengal dye into the cornea. This limitation is being addressed by several approaches, including lipophilic prodrugs, nanoparticles, and physical approaches for enhanced delivery, including iontophoresis and ultrasound.