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Observation of Retrocorneal Plaques in Patients With Infectious Keratitis Using Anterior Segment Optical Coherence
Yuki Takezawa1, Takashi Suzuki, Atsushi Shiraishi
1*Department of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan; and †Ishizuchi Eye Clinic, Shonai, Niihama, Ehime, Japan.
Purpose:
Endothelial plaques are a typical characteristic in patients with fungal keratitis. However, bacterial keratitis and herpetic keratouveitis are rarely associated with fibrin formation on the retrocorneal surface. This study was conducted to examine plaques attached to the endothelium in patients with infectious keratitis using anterior segment optical coherence tomography (AS-OCT).
Methods:
Seventeen patients (10 women and 7 men; mean age, 75 ± 15.5 years) suspected to have infectious keratitis with retrocorneal plaques were included. AS-OCT was used to acquire a scan of the retrocorneal plaque at the patient's first visit.
Results:
Based on the culture results and detection of viral DNA, the patients were diagnosed with fungal keratitis (6 patients), bacterial keratitis (8 patients), and herpetic keratouveitis (3 patients). Examination of the cornea using AS-OCT showed a clear boundary between the corneal endothelial surface and plaque in 8 patients with bacterial keratitis and in all patients with herpetic keratitis. Moreover, a space between the corneal endothelial surface and plaque was found in 3 patients with bacterial keratitis. In 5 patients with fungal keratitis, the AS-OCT images showed an unclear boundary between the corneal endothelial surface and plaque, and high reflection of the plaque was extended from the corneal lesion.
Conclusions:
Endothelial plaques in patients with fungal keratitis could continue from the corneal lesion. Observation of retrocorneal plaques using AS-OCT could be used in the diagnosis of infectious keratitis.
Insights
Anterior segment optical coherence tomography (AS-OCT) helps differentiate infectious keratitis types. Fungal keratitis plaques show unclear boundaries, unlike bacterial keratitis or herpetic keratouveitis, aiding diagnosis.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Medical Imaging
Background:
- Endothelial plaques are common in fungal keratitis but rare in bacterial keratitis and herpetic keratouveitis.
- Distinguishing causes of infectious keratitis is crucial for appropriate treatment.
- Anterior segment optical coherence tomography (AS-OCT) offers high-resolution imaging of ocular structures.
Observation:
- AS-OCT was used to examine retrocorneal plaques in 17 patients with suspected infectious keratitis.
- Patients were diagnosed with fungal keratitis (6), bacterial keratitis (8), or herpetic keratouveitis (3) based on cultures and viral DNA detection.
- AS-OCT visualized plaque characteristics, including boundary clarity with the corneal endothelium and plaque extension.
Findings:
- Bacterial keratitis and herpetic keratouveitis showed clear boundaries between plaques and the corneal endothelium on AS-OCT.
- A space was observed between the plaque and endothelium in some bacterial keratitis cases.
- Fungal keratitis plaques displayed unclear boundaries and high reflection extending from the corneal lesion in AS-OCT images.
Implications:
- AS-OCT imaging of retrocorneal plaques can aid in differentiating fungal keratitis from bacterial keratitis and herpetic keratouveitis.
- The distinct AS-OCT features of plaques associated with fungal keratitis suggest a continuous lesion.
- This imaging modality can potentially improve the diagnostic accuracy for infectious keratitis.
