The purpose of this study was to compare bacterial isolation rate using a corneal impression membrane (CIM) and a sharp instrument for obtaining corneal samples from patients with suspected microbial keratitis (MK). Data was retrospectively collected for all patients that had corneal samples taken for presumed MK between May 2014 and May 2020. Prior to May 2017 samples were collected by scraping the edges of the ulcer with a blade. From May 2017, samples were collected by placing a CIM (Millicell cell culture insert) against the ulcer. All corneal samples were processed using the same conventional diagnostic culture method. A total of 3099 corneal samples were included, of which 1214 (39.2%) were corneal scrapes and 1885 (60.9%) CIMs. Microorganisms were isolated from 235 (19.4%) and 1229 (65.2%) cases using a corneal scrape and CIM, respectively (p < 0.001). Of routinely described pathogenic microorganisms, there were significant increases in the isolations of S. aureus (2.4% to 11.3%) and Serratia (0.5% to 1.7%) using the CIM and no significant changes in the isolations of S. pneumoniae and P. aeruginosa. No significant differences were seen between the isolation rates of fungi or Acanthamoeba species. There was a significant increase in the isolation rates of other Streptococcal species (0.7% to 6.9%) and CNS species, specifically, S. epidermidis (2.1% to 26.2%), S. capitis (0.4% to 2.6%) and S. warneri (0.3% to 1.6%) using the CIM. The simplified CIM sampling method is an effective method for collecting corneal samples from patients with presumed MK in clinical practice.

Topical fluoroquinolones (FQs) are an established treatment for suspected microbial keratitis. An increased FQ resistance in some classes of bacterial pathogens is a concern. Some recently developed FQs have an extended spectrum of activity, making them a suitable alternative for topical ophthalmic use. For example, the new generation FQs, avarofloxacin, delafloxacin, finafloxacin, lascufloxacin, nadifloxacin, levonadifloxacin, nemonoxacin and zabofloxacin have good activity against the common ophthalmic pathogens such asStaphylococcus aureus,Pseudomonas aeruginosa,Streptococcus pneumoniaeand several of theEnterobacteriaceae. However, because there are no published ophthalmic break-point concentrations, the susceptibility of an isolated micro-organism to a topical FQ is extrapolated from systemic break-point data and wild type susceptibility. The purpose of this review is to compare the pharmacokinetics and pharmacodynamics of the FQs licensed for topical ophthalmic use with the same parameters for new generation FQs. We performed a literature review of the FQs approved for topical treatment and the new generation FQs licensed to treat systemic infections. We then compared the minimum inhibitory concentrations (MIC) of bacterial isolates and the published concentrations that FQs achieved in the cornea and aqueous. We also considered the potential suitability of new generation FQs for topical use based on their medicinal properties. Notably, we found significant variation in the reported corneal and aqueous FQ concentrations so that reliance on the reported mean concentration may not be appropriate, and the first quartile concentration may be more clinically relevant. The provision of the MIC for the microorganism together with the achieved lower (first) quartile concentration of a FQ in the cornea could inform management decisions such as whether to continue with the prescribed antimicrobial, increase the frequency of application, use a combination of antimicrobials or change treatment.

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In this paper, we investigate the effect of sedation using low-dose propofol on patient reported outcome measures (PROMS) in patients undergoing cataract surgery. This is a randomised, single-blinded observational prospective study. Patients undergoing elective cataract surgery using peribulbar anaesthesia over consecutive cataract lists were selected for this trial. Patients were randomised to receive either no sedation or low-dose propofol (20 to 30 mg followed by 10 mg increments until the patient developed slurred speech alone) prior to the administration of local anaesthesia. Pain, satisfaction, anxiety, needle recall, pulse, and blood pressure (BP) were measured. A total of 97 patients were included, 50 of whom received propofol. There were 4 senior surgeons and anaesthetists. There were no ocular or systemic complications and all patients had uncomplicated surgery. Anxiety (p = 0.026), needle recall (p < 0.001), difference in systolic BP (p = 0.043), and pulse (p = 0.046) were dependent on patient age (p < 0.001) and the use of propofol (p = 0.007). Lower pain was associated with propofol (p = 0.008), as well as lower anxiety (p = 0.002), and increased patient age (p = 0.014). The administration of propofol was significantly associated with lower needle recall (p < 0.001), pre- to post-operative difference in systolic BP (p = 0.029), and mean BP (p = 0.044). Low-dose propofol given immediately prior to administration of local anaesthesia was associated with reduced pain and needle recall, as well as lower BP.