Detection of Endothelial Plaque in Microbial Keratitis Using Anterior Segment Optical Coherence Tomography

Area of Science:

• Ophthalmology
• Medical Imaging
• Infectious Diseases

Background:

• Microbial keratitis is a significant cause of vision loss.
• Endothelial plaque is a key indicator in microbial keratitis.
• Accurate detection of endothelial plaque is crucial for timely treatment.

Purpose of the Study:

• To assess the consistency of grading endothelial plaque using anterior segment optical coherence tomography (ASOCT) by different graders.
• To compare the detection of endothelial plaque by ASOCT with traditional slit lamp examination.
• To evaluate ASOCT's reliability in diagnosing microbial keratitis.

Main Methods:

• A diagnostic concordance study involving 150 patients with confirmed bacterial or fungal keratitis.
• Two masked ophthalmologists independently graded ASOCT images for endothelial plaque presence and morphology (round and flat).
• Agreement was assessed using Cohen's kappa, sensitivity, specificity, and logistic regression.

Main Results:

• ASOCT demonstrated excellent inter-grader agreement (kappa 0.84-0.88) and substantial to near-perfect intra-grader agreement (kappa 0.70-0.86).
• ASOCT detected endothelial plaque in 55.3% of eyes, compared to 6.0% by slit lamp examination.
• Slit lamp examination showed low sensitivity (6.2%-16.3%) for plaque detection compared to ASOCT, despite high specificity (>94%).
• Poor visual acuity and bacterial infection were associated with increased disagreement between ASOCT and slit lamp findings.

Conclusions:

• ASOCT provides a reproducible and reliable method for detecting endothelial plaque in microbial keratitis.
• Slit lamp examination significantly under-detects endothelial plaque compared to ASOCT.
• ASOCT imaging should be considered for routine evaluation of microbial keratitis.