Infectious Keratitis

This study aims to detect the effect of sodium chloride 5% solution as an adjuvant treatment with antimicrobial therapy in treatment of bacterial infectious keratits and to assess whether NaCl 5% accelerates epithelial healing, improves microbial eradication, and enhances visual outcomes in bacterial infectious keratitis.

Microbial keratitis is a severe and often blindness-inducing pathology which represents today the first reason for long-term hospitalization (more than 5 days) in ophthalmology. Its diagnosis is clinical and leads to an immediate hospitalization in the presence of serious criteria (Mackie classification). The entire process of microbiological diagnosis requires several days before etiological confirmation and therefore delays the initiation of targeted therapy. Recently, new PCR systems allowing the detection of 18 to 27 pathogens in 75 minutes have been developed. Their use could thus be transposed to ophthalmology by adapting the microbiological diagnostic technique to samples currently taken by swabbing the cornea. The investigators will compare their diagnosis performance versus conventional methods on patients who suffered for a microbial keratitis with severity criteria.

Infectious keratitis is a significant cause of partial vision loss and blindness and places a large burden on eye care professionals. One of the main challenges for the ophthalmologist when presented with a case of suspected microbial keratitis is the determination of the subtype of keratitis. It must be determined whether the origin of the infection is bacterial, viral, fungal, or parasitic, in order to prescribe a correct, effective treatment aimed at the causative pathogen. In daily practice this can be challenging, and general treatments with antibiotics are prescribed. Some cases then experiences deterioration, resulting in more patients visits and further rounds of invasive treatments and progressive vision deterioration. This project is designed to break this cycle of nonspecific diagnosis, suboptimal treatment, and progressive worsening of vision with increased interventions. New, advanced diagnostics will be brought into the clinic to provide additional information which, if our hypothesis is correct, will result in more rapid and accurate diagnosis of the keratitis subtype. This will translate into earlier administration of a more targeted treatment, avoiding the repeated round of non-targeted treatment and progressive worsening of the patient's vision. This can directly reduce to number of clinic visits and specialist time required for treatment and follow-up of keratitis, knowledge of how the eye responds to various microbes by initiating a specific cascade of molecular inflammatory signals and changes in protein expression in the tear film. Using in vivo confocal microscopy (IVCM) we will document the cellular status of the cornea and identify microbes infecting the cornea in real-time. Secondly, tear samples will be obtained from patients with keratitis to evaluate and quantify the molecular cytokine signatures associated with specific microbial species, confirmed by microbiological culture. We will for the first time develop cytokine profiles for the various types of infection, identifying diagnostic cytokines which in the longer term can lead to development of rapid point-of-care biomarker diagnostics. The project aims are translated into the following hypotheses: H1: In vivo confocal microscopy imaging features detect microbial keratitis consistent with clinical assessment and outcome at a greater frequency than microbiological culture results. H2: Cytokine profiles (or a subset of molecules) in the eye are specific for viral, bacterial, fungal, or amoebic keratitis; and H3: A combination of in vivo confocal microscopy and molecular profiling of the tear film can yield a specific keratitis diagnosis closely matching the clinical progression and outcome of keratitis.