The Role of in Vivo Confocal Microscopy in Diagnosing and Managing Infectious Keratitis in Deployed French Military Personnel: A Case Series

Fungal and amoebic keratitis are rare but serious infections that can lead to significant vision loss and are often difficult to diagnose promptly, particularly in resource-limited environments. Although conventional cultures and PCR have notable diagnostic limitations, in vivo confocal microscopy (IVCM) offers rapid and accurate pathogen detection. This retrospective case series examines four cases of infectious keratitis in deployed military personnel, highlighting the diagnostic and clinical utility of IVCM. All patients were young males, with a mean age of 29.75 years. Half had a history of improper contact lens use, although the others sustained ocular trauma from plant material. Corneal cultures performed in the field were uniformly negative, underscoring the limitations of traditional diagnostics in austere settings. In contrast, IVCM performed after the patients were repatriated enabled timely identification of filamentous fungi and amoebic cysts, allowing for targeted antimicrobial therapy. Patients experienced prolonged hospitalizations (mean: 2 months) and extended treatment courses (up to 9 months), with three undergoing amniotic membrane transplantation. Early diagnosis using IVCM contributed to the prevention of severe complications such as corneal perforation and endophthalmitis. These findings support the role of IVCM as a critical diagnostic modality in managing complex corneal infections when conventional microbiological tools are unavailable or insufficient.