Optical Coherence Tomography Based Pathogen Detection In Different Kinds Of Keratitis

Published 2022 - 40th Congress of the ESCRS

Reference: FPM06.07 | Type: Free paper | DOI: 10.82333/8164-3d59

Authors: Haidar Khalil* ¹ , Nino Hirnschall ¹ , Klemens Waser ¹ , Matthias Bolz ¹ , Peter Laubichler ¹

¹Dpt. for Ophthalmology and Optometry, Kepler University Linz,Linz,Austria

Purpose

As conventional corneal scraping with bacterial culturing has several disadvantages such as long duration until diagnosis, invasiveness and lacks alternatives, there is demand for a novel non-invasive, rapid test in keratitis management. Purpose of this study was to develop an algorithm based on optical coherence tomography (OCT) imaging (and cytokine levels from tear samples) to distinguish between different kinds of pathogenes. Commonly, the presence and nature of bacterial pathogens is determined by taking scrapes from the cornea, subsequent Gram stain and examination of microbiological cultures. Major problems in therapeutic decision-making pose the long duration of bacterial culturing for pathogen detection (approximately one week).

Setting

Prospective clinical trial. Patients will be recruited from the outpatient clinic of the Department of Ophthalmology, Kepler University Clinic, Linz, Austria.

Methods

Patients with keratitis without previous ocular surgery are included in this study. This study is part of a multicenter trial. At the moment only data from our clinic are available. All patients undergo swept source OCT measurements (CASIA-2 (Tomey, Japan), MS-39 (CSO, Italy). Following morphological findings in OCT will be analysed: corneal thickness (μm), infiltrate thickness (μm), reflectivity of the infiltrate. Furthermore, a tear sample of the conjunctival lavage will be collected, stored at - 80° Celsius. Corneal scraping samples will be collected by an experienced ophthalmologist. This step is not study related, but part of the diagnostic gold standard for keratitis. The probe will be cultivated as a standard procedure.

Results

Results: In total, 392 patients will be included in 5 different centers across Europe. At the moment preliminary results of one center (Linz, Austria) are available. Mean age was 62 years (SD: 12 ). ssOCT measurements showed a corneal thickness in the area of the infiltrate of (439μm, SD: 123) and infiltrate thickness was found to be (215μm; SD:33). A comparison between Gram+ and Gram- OCT images will be presented.

Conclusions

Conclusion: Gram+ and Gram- bacteria have specific features that are represented in OCT imaging. More data is needed to develop an algorithm to automatically detect pathogens in keratitis patients using OCT technology.