In Vivo Confocal Microscopy Findings of a Rare Cryptococcus neoformans Keratitis.

Purpose: To report a rare case of fungal keratitis caused by Cryptococcus neoformans, highlighting its unique morphological features using in vivo confocal microscopy (IVCM).

Methods: This was a retrospective case report. A 66-year-old man presented with foreign body sensation and blurred vision in his left eye for over 10 months.

Results: His best-corrected visual acuity was 20/20. Slit-lamp examination revealed a gray-white lesion approximately 4-5 mm in the superficial layer of the central cornea without epithelial defects. The IVCM images revealed numerous round or round-like pathogens, each with a central highly reflective body surrounded by a dark ring, ranging in size from 5 to 30 µm, and to a maximum of 85 µm, observed in the corneal epithelium and superficial stroma. No obvious inflammatory cell infiltration was observed in the lesions or endothelium. C. neoformans infection was confirmed. The round pathogens completely disappeared after 8 weeks of treatment with topical amphotericin B and voriconazole eye drops.

Conclusion: Fungal keratitis caused by C. neoformans is rare and easily overlooked due to atypical clinical signs and symptoms. This case reports the unique morphological features of C. neoformans in the cornea using IVCM for the first time, facilitating rapid, noninvasive auxiliary diagnosis of C. neoformans keratitis and treatment follow-up.