PSEUDOMONAS DETECTION WITH OCT IN KERATITS

Pseudomonas is one of the leading causes for bacterial keratitis, predominatly in contact lens users. Conventional corneal scraping with bacterial culturing has several disadvantages such as long duration until diagnosis, invasiveness  and low sensitivity. There is demand for a novel non-invasive, rapid test in Pseduomonas keratitis management. Purpose of this study is to investigate certain OCT patterns pathognomonic for pseudomonas. 

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

Measurement of the Cornea in patients with keratitis are performed using CASIA 2 (Tomey, Japan), which is a SS-OCT that allows high resolution imaging of the anterior segment of the eye. Following morphological findings in optical coherence tomography were analysed: corneal thickness (μm), infiltrate thickness (μm), entropy of the infiltrate area (measured using ImageJ). Corneal scraping was performed to determine the underlying pathogen.

From our cohort of 25 eyes, 7 eyes had a keratitis due to pseudomonas. Mean age in the keratitis group was 26 years. In 6 of those eyes, keratitis was associated to contact lens wear and one was due to a trauma. Mean corneal thickness was 820µm (SD +/- 193µm), mean infiltrate thickness 347µm (SD +/- 125µm). Mean tissue gain ratio of 1.3 was measured in the area of the infiltrate, compared to the not affected side of the cornea in the same eye. Partial least squares regression model was used to determine parameters that have influence on the detection of pseudomonas.