Deep Fungal Stromal Keratitis After Cataract Surgery: A Case Report

Fungal keratitis is a vision-threatening infection that typically originates at the ocular surface and gradually invades the deeper layers of the cornea. We report a rare fungal keratitis confined to the deep stromal layer that developed following cataract surgery. An 81-year-old woman presented with a creeping white opacity on the posterior corneal surface in the right eye. Anterior segment optical coherence tomography revealed a hyper-reflective lesion at the posterior cornea, and in vivo confocal microscopy showed filamentous structures in the deep stroma, supporting the diagnosis of fungal keratitis. Corneal scraping was not feasible because the lesion was deep within the cornea. Initial treatment with natamycin and fluconazole was ineffective, and the infection progressed despite topical and systemic voriconazole. Ultimately, the infection resolved after administering amphotericin B via topical, intrastromal, and intravenous routes. The patient's condition improved without requiring therapeutic keratoplasty. This case illustrates the diagnostic value of in vivo confocal microscopy in deep stromal fungal keratitis. It emphasizes the importance of selecting appropriate antifungal agents when first-line treatments are ineffective.