Rose Bengal Electromagnetic Activation with Green Light for Infection Reduction Study: A Randomized Controlled Trial

To determine the effect of adjunctive rose bengal (RB) photodynamic therapy (PDT) in the treatment of fungal, Acanthamoeba, and smear- or culture-negative infectious keratitis.

International, randomized, double-masked, sham-controlled clinical trial.

Patients with corneal ulcers randomized in a 1:1 fashion to 1 of 2 treatment arms: (1) topical antimicrobial therapy plus sham RB PDT or (2) topical antimicrobial therapy plus RB PDT.

The primary outcome was best spectacle-corrected visual acuity (BSCVA) at 6 months. Secondary outcomes included BSCVA at 3 weeks and 3 months; infiltrate, scar size, or both at 3 weeks, 3 months, and 6 months; and corneal perforation (CP), the rate of therapeutic penetrating keratoplasty (TPK), or both; and microbiological cure rate.

Three hundred thirty patients were enrolled. Isolated organisms included filamentous fungus (n = 301 [91%]), Acanthamoeba (n = 10 [3%]), and negative culture or smear findings (n = 19 [6%]). No evidence was found of a benefit of RB PDT versus sham for BSCVA at 6 months (-0.0004; 95% confidence interval [CI], -0.13 to 0.13; P = 0.62). Evidence was found of a statistically significant interaction between treatment arm and fungal organism with regard to BSCVA (P = 0.02). Rose bengal PDT improved BSCVA among eyes with Fusarium infections (difference, -0.17 logarithm of the minimum angle of resolution [logMAR]; 95% CI, -0.37 to 0.03 logMAR), but worsened BSCVA among eyes with Aspergillus infections (difference, 0.39 logMAR; 95% CI, -0.03 to 0.80 logMAR). Scar size was 0.45 mm smaller in the RB PDT group at 3 weeks (95% CI, -0.76 to -0.15 mm; P = 0.004), but this finding was no longer statistically significant at 3 and 6 months. No difference between groups was found in rates of CP, TPK, or microbiological cure.

We were unable to find a benefit of adjuvant RB PDT overall. Future directions may include trying alternative photosensitizers or other treatment algorithms.

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.