Evaluation Of Methylene Blue–Mediated Photodynamic Therapy In A Rabbit Model Of Candida Keratitis
Published 2026 - 44th Congress of the ESCRS
Reference: PP20.10 | Type: Free paper | DOI: 10.82333/hv3g-vf79
Authors: Dr Yavuz Kemal Aribas* 1 , Dr Sidre Erganiş 2 , Prof. Dr Ayşe Kalkancı 2 , Prof. Dr Kamil Bilgihan 3
1Ophthalmology,Hacettepe University Medical School,Ankara,Türkiye, 2Microbiology,Gazi University Medical School,Ankara,Türkiye, 3Ophthalmology,Gazi University Medical School,Ankara,Türkiye
Purpose
To investigate the clinical and microbiological effects of methylene blue–mediated photodynamic therapy (PDT) relative to topical voriconazole, methylene blue (MB) staining alone, and no treatment in an experimental Candida auris fungal keratitis model.
Setting
Experimental animal study using a rabbit eye Candida auris keratitis model.
Methods
A Candida auris fungal keratitis model was induced in rabbit eyes and allowed to develop for 3 days after inoculation. Twenty-four eyes were allocated into four groups (n=6 each): topical voriconazole, methylene blue (MB) staining alone, untreated control, and photodynamic therapy (PDT) consisting of MB staining followed by red-light irradiation (630–680 nm, 20 mW/cm²) for 15 minutes. Voriconazole was administered from day 3 until the endpoint only in its group, while PDT was applied once on day 3; no antifungal therapy was given to the other groups. Clinical and staining scores were assessed at baseline and endpoint. Changes were analyzed using the Kruskal–Wallis test with Dunn–Bonferroni post hoc analysis and Spearman’s rank correlation.
Results
Baseline clinical and corneal staining scores were comparable among groups (all p>0.05). Significant intergroup differences were observed in changes in both clinical and staining scores (both p<0.001). Mean change in clinical score was −3.17±1.84 in the PDT group and −2.17±1.17 in the voriconazole group, compared with worsening in the MB-only (4.83±2.04) and control groups (4.83±2.48). Mean change in staining score was −2.33±1.03 (PDT) and −1.83±0.98 (voriconazole) versus 0.33±0.52 (MB-only) and 0.50±1.23 (control). PDT and voriconazole differed from MB-only and control (adjusted p<0.05) and were similar to each other. Clinical and staining score changes were strongly correlated (ρ=0.779, p<0.001).
Conclusions
This experimental study suggests that methylene blue–mediated photodynamic therapy may represent a promising adjunctive approach in fungal keratitis. The observed findings support further investigation to better define its potential therapeutic role and to clarify optimal treatment parameters in future experimental and clinical studies.