Case Report: Confocal microscopy in the early diagnosis of microsporidial keratitis

TL;DR

A rare case of microsporidial keratitis was diagnosed early using confocal microscopy, leading to successful treatment and improved vision.

Contribution

Demonstrates the utility of in vivo confocal microscopy for early non-invasive diagnosis of microsporidial keratitis.

Findings

In vivo confocal microscopy detected hyperreflective spore casings and vesicular clusters indicative of microsporidia.

Therapeutic penetrating keratoplasty and targeted therapy preserved the patient's eye and improved vision.

Confocal microscopy complements molecular methods like mNGS in diagnosing rare corneal infections.

Abstract

This report describes a rare case of microsporidial stromal keratitis (MSK) complicated by corneal perforation in a 69-year-old male farmer with a 5-month history of ocular redness, pain, photophobia, and epiphora. In vivo confocal microscopy (IVCM) revealed pathognomonic findings—hyperreflective double-walled spore casings and vesicular clusters, providing the earliest diagnostic clues for microsporidia infection. Subsequent metagenomic next-generation sequencing (mNGS) and histopathology confirmed Microsporidia species. The patient underwent therapeutic penetrating keratoplasty followed by targeted anti-microsporidial therapy, achieving globe preservation and visual improvement. This case underscores IVCM’s pivotal role in diagnosing MSK, particularly in atypical presentations. Because MSK remains a rare corneal disorder, its insidious progression necessitates high clinical vigilance. In summary, IVCM’s ability to detect microsporidial structures in real-time significantly enhances early diagnosis, complementing molecular methods like mNGS. We conclude that IVCM, as a non-invasive and rapid diagnostic tool, provides a convenient and efficient means for the early differentiation of challenging corneal infections.

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