Clinical outcome in patients with infectious keratitis treated with Rose Bengal Photodynamic Antimicrobial Therapy (RD-PDAT) at the Federal University of Sao Paulo (UNIFESP)

Abstract

Purpose : To determine the clinical outcomes in patients treated with RB-PDAT for infectious keratitis (IK).
We retrospectively reviewed patient charts with IK that underwent RB-PDAT at UNIFESP between March 2023 and November 2023.

Methods : An analysis of sex, age, and risk factors was performed. Ophthalmic exam consisted of best corrected visual acuity (BCVA), slit-lamp exam, and photography. Corneal scraping was carried out. A patient was considered eligible if they received appropriate standard medical therapy without clinical improvement.
Patients received a 30-minute dose of topical RB (0.1% RB in 0.9% sodium chloride) which was applied in 3-minute intervals to the de-epithelialized cornea with an 8-mm sponge soaked with RB solution. This was followed by irradiation with a 6mW/cm² custom-made green LED source (525nm) - provided by the Ophthalmic Biophysics Center from the Department of Ophthalmology of the Bascom Palmer Eye Institute - for 15 minutes (5.4J/cm²).
The main outcome measure was RB-PDAT success, defined as avoidance of therapeutic penetrating keratoplasty (TPK). Secondary outcomes included time from RB-PDAT to clinical resolution.

Results : 15 patients (15 eyes) were enrolled. The gender distribution was 6 males (40%) and 9 females (60%). The average age was 51.6 years (SD 18.22, 31-78 years). A microbiologic diagnosis was confirmed through culture in 11 patients, whereas, in 4 the diagnosis remained elusive. Acanthamoeba spp. (3 cases) and yeast fungi were the most frequent microbe identified (3 cases), followed by filamentous fungi and S. pneumoniae (2 cases) and P. aeruginosa (1 case).
Most individuals reported a history of contact lens wear (64%) while 21% reported ocular trauma and contact with soil. Additional comorbidities included previous use of topical immunosuppressor (7%).
RB-PDAT was considered not successful in 4 patients (28.57%) where no clinical response was observed, necessitating subsequent TPK after a mean of 83±67 days. The outcome was considered successful in 11 (73.34%) individuals. In these 11 individuals, time to clinical resolution after RB-PDT was 28.5 ± 16.4 days.

Conclusions : RB-PDAT is a potential adjunct therapy for IK that may reduce the need for a therapeutic penetrating keratoplasty.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

FIGURE: patients before RB-PDAT and after 21 days and 3 months of treatment.