Evaluation Of The Efficacy Of Intrastromal Antifungal Injection In Fungal Keratitis And Prognostic Factors Affecting Treatment Response

To assess clinical outcomes of intrastromal antifungal (ISAF) injections in fungal keratitis and to identify etiological and prognostic factors differentiating responsive and refractory cases.

Department of Ophthalmology, Bursa City Hospital, University of Health Sciences, Bursa, Türkiye.

This retrospective study included patients diagnosed with fungal keratitis between 2023 and 2025 who received ISAF injections. Demographic characteristics, clinical findings, microbiological results, treatment regimens and number of injections were recorded. All patients were initially treated with empiric fortified topical antifungal therapy. In cases showing inadequate response, intrastromal voriconazole (50 µg/0.1 ml) and/or amphotericin B (5 µg/0.1 ml) were administered. The number and duration of injections, time to healing and additional treatments were documented. Healing characteristics (epithelial closure, resolution of hypopyon and decrease in infiltrate size) were evaluated through biomicroscopic examination

Twenty-nine patients (mean age 54.2 years) were included. The most common predisposing factor was prior corneal surgery. Candida (34.5%) and Fusarium (24.1%) were the most isolated organisms. The mean time to initiation of ISAF therapy was 5.62 ± 5.94 days, with a mean of 3.79 ± 3.83 injections. Patients were classified as ISAF-responsive (n=20) or refractory (n=9). The mean healing time in the responsive group was 38.7 ± 19.1 days. In the refractory group, five patients underwent corneal cross-linking and seven required therapeutic keratoplasty. A longer interval between symptom onset and initial presentation (22.78 days, p=0.013) and a baseline lesion size greater than 6 mm (p<0.001) were significantly associated with treatment failure.

Fungal keratitis remains difficult to manage due to limited stromal penetration of topical agents and drug-related toxicity. ISAF injection appears to be a valuable adjunct in cases unresponsive to conventional therapy. Delayed presentation and larger lesion size are key negative prognostic factors and should be considered when planning management.