Ocular Microbiology and Immunology Group
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2020 OMIG Abstract

Evaluation of Rose Bengal Photodynamic Antimicrobial Therapy as an Adjunctive Treatment for Severe Keratitis

Wirley Alves de Mendonça Júnior, MD¹, Talita Trevizani Rocchetti, PhD¹, Denise de Freitas, MD, PhD¹,
JarbasCaiado de Castro Neto, PhD², Ana Luisa Hofling-Lima, MD, PhD^1
1Ophthalmology Department, Federal University of São Paulo-São Paulo;
²Physics Institute, University of São Paulo - São Carlos, Sao Paulo, Brasil

Methods: Four patients with severe keratitis (one methicillin-resistant Staphylococcus aureus (MRSA), one methicillin-susceptible S. aureus (MSSA), one Moraxella spp. and one Fusarium solani) not responsive to standard medical care were treated with RB-PDAT. The areas of epithelial defect were 95, 90, 24.44 and 1mm² while the stromal opacification areas were 95, 40, 24.44 and 6mm², respectively. The lengths of standard medical treatment prior to the procedure were 7, 1, 18 and 21 days, respectively. RB-PDAT was performed by applying a solution of rose bengal 0.1% in balanced salt solution to the de-epithelialized cornea for 30 minutes (one drop every three minutes), followed by irradiation with a 7.15 mW/cm² custom-made green LED source for 15 minutes (6.43 J/cm²). In order to evaluate RB-PDAT activity against the infecting microorganism, tests were performed “in vitro” as well.

Results: All eyes had clinical resolution of infection in 40 (MRSA), 16 (MSSA), 102 (Moraxella spp.) and 67 (F. solani) days after RB-PDAT. Patients with Moraxella spp. and F. solani keratitis required a second treatment, 34 and 20 days after the first procedure, respectively. Patient with MSSA infection was the only who had a diffuse thin cornea (480 micra) due to a very compromised ocular surface and had a small corneal perforation 9 days after the procedure, which was managed with cyanoacrylate glue. None of the cases needed therapeutic keratoplasty.

Conclusion: RB-PDAT can be considered as an adjunctive therapy in cases of severe and progressive keratitis despite standard medical care, especially to avoid therapeutic keratoplasty.

Disclosure: N