Inter-Device Comparison Of Corneal Parameters In Keratitis: Results From Anterior Segment Optical Coherence Tomography Measurements

Infectious keratitis is a vision-threatening condition associated with significant medical and socioeconomic burden. While traditional diagnostic methods such as microbiological cultures can be unreliable and time-consuming, optical coherence tomography (OCT) has demonstrated its potential for pathogen differentiation in previous studies. However, with the increasing availability of different OCT systems, the comparability of measurement results and the influence of the examiner remain unclear. This study aims to investigate the consistency of OCT-based corneal parameters across different devices and examiners.

This prospective study is part of the VICTORIA project and was conducted at Kepler University Hospital Linz. Patients with infectious keratitis were recruited for participation.

After obtaining informed consent, corneal scans were performed using three different OCT devices: CASIA 2, Heidelberg Spectralis, and MS-39. Each scan was independently measured by three examiners to assess inter-individual variability. Additionally, a corneal swab was collected for microbiological analysis to correlate the OCT-derived parameters with the identified pathogens.

The results demonstrate that all three OCT devices (CASIA 2, Spectralis, MS-39) provided consistent and comparable measurements for central corneal thickness (CT), infiltrate diameter (ID), and infiltrate thickness (IT). CASIA 2 tended to show higher values for IT and ID compared to the other devices. The inter-investigator analysis revealed no significant differences between examiners within the same device. The association of OCT parameters with microbiologically identified pathogens confirmed differences in IT and CT between Gram-negative and Gram-positive infections.

OCT-based measurements are a reliable tool for evaluating corneal parameters in infectious keratitis. The CASIA 2, Heidelberg Spectralis, and MS-39 devices demonstrated comparable results with minimal inter-individual variability. CASIA 2 tended to provide higher values for infiltrate thickness and diameter. The correlation with microbiologically identified pathogens confirmed differences between Gram-negative and Gram-positive infections, highlighting the diagnostic relevance of OCT in guiding treatment planning.