Rose Bengal Photodynamic Antimicrobial Therapy: A Pilot Safety Study.

Area of Science:

• Ophthalmology
• Photodynamic Therapy
• Corneal Research

Background:

• Corneal infections pose a significant threat to vision.
• Photodynamic antimicrobial therapy (PDAT) offers a novel approach to combat microbial keratitis.
• Rose Bengal (RB) is a photosensitizer with potential for PDAT.

Purpose of the Study:

• To evaluate in vivo corneal changes following Rose Bengal photodynamic antimicrobial therapy (RB-PDAT).
• To assess the safety and potential long-term effects of RB-PDAT on corneal tissue.

Main Methods:

• New Zealand White rabbits underwent central corneal deepithelialization.
• Treatment groups included balanced salt solution, RB alone, green light alone, and RB-PDAT (0.1% RB with green light).
• Corneal healing, anterior segment optical coherence tomography (AS-OCT), and terminal deoxynucleotidyl transferase-mediated UTP-biotin-nick-end labeling (TUNL) assay were utilized for evaluation.

Main Results:

• All rabbits achieved complete corneal reepithelialization with clear corneas post-treatment.
• AS-OCT revealed collagen cross-linking and RB fluorescence in treated corneas, with no sustained cytotoxic effects observed via TUNL assay at 5 weeks.
• Retention of RB dye in the corneal stroma did not lead to long-term oxidative stress.

Conclusions:

• RB-PDAT using 0.1% Rose Bengal is a safe and effective procedure for the cornea.
• Clinical and histopathological assessments showed no significant differences compared to control groups.
• Long-term safety is supported by the absence of evidenced oxidative stress in corneas with retained RB dye.