AIMS 1. To establish the patient demographics, risk factors, causative organisms, levels of antibiotic resistance, clinical presentations and treatment patterns of keratitis at a tertiary referral hospital in Australia. 2. To establish any change in these factors over 5 years. 3. Establish the factors associated with poor outcomes. METHODS: A retrospective audit of all patients who had a corneal culture in 5 years was conducted. Patients' clinical information was gathered from medical records and smear, culture and antibiotic resistance results were gathered from the local microbiology database. Associations between risk factors for keratitis and patient variables were analysed statistically. Outcome of a patient's episode of keratitis was classified as poor using final criteria. Trends over time in variables were analysed using linear regression. RESULTS: Two hundred and fifty-three (253) corneal cultures of 231 patients were included. Sixty percent (60%) of patients were male and there was a bimodal distribution in the age of presentation. Common risk factors for keratitis were contact lens wear (22%), ocular surface disease (18%), ocular trauma (16%) and prior ocular surgery (11 %). Corneal cultures were positive in 65% of cases and Pseudomonas aeruginosa (27%), coagulase-negative staphylococci (13%), Staphylococcus aureus (12%) and fungi (7%) were recovered. There was significant variation in the monthly recovery of P. aeruginosa (p=0.04) and fungi (p=0.02) which were more frequent in summer months, while Streptococcus pneumonia (p=0.04) was more common in winter months. Antibiotic resistance of cultured bacteria to cephalothin increased significantly (2% to 12%; p=0.02). Final vision of 6/12 or better was found in 48% (100) of cases while a poor outcome was seen in 28% (58) of cases. Multivariate analysis showed that the relative risk of a patient having a poor outcome was 4.3x (confidence interval [Cl] 2.0 to 9.5) if they had severe keratitis, 4.1 x (Cl 1.8 to 9.5) if they had keratitis related to ocular surface disease and 3.8x (Cl 1.8 to 8.3) if they were over 50 years old. CONCLUSIONS 1. In this series the most common risk factor for keratitis was contact lens wear and the most commonly isolated organism was P. aeruginosa which had seasonal variation in rate of recovery. 2. Keratitis related to contact lens wear became more frequent while keratitis related to prior ocular surgery became less frequent. 3. A poor outcome is more likely in patients with severe keratitis, keratitis related to prior ocular surface disease or older age.

Microbial keratitis is the most serious, and only potentially blinding complication of contact lens wear. To further understand and reduce the risk of this disease, incidence rates and risk factors have been estimated in numerous studies. Since these studies were conducted, new lens types have been introduced designed to reduce the risk of infection. It was hypothesised that the issues of contact lens related hypoxia and poor lens hygiene could be addressed by the introduction of silicone hydrogel and daily disposable lenses respectively. This thesis describes the incidence of and risk factors for contact lens related microbial keratitis in Australia and New Zealand. The incidence of infection was determined by capturing all cases of contact lens related presumed microbial keratitis in a 12-month surveillance study, and by estimating the number of lens wearers using a population-based phone survey. Characteristics of the cases and controls were compared to estimate risk factors. In Australia, rates of infection with daily and overnight wear of hydrogel lenses were similar to previously published reports (1.9 [95%CI]:1.8-2.0] and 19.5 [95%CI:14.6-29.5] per 10,000 wearers respectively). Compared to the incidence of infection with hydrogel lenses, silicone hydrogel lenses had a higher rate in daily wear (11.9 [95%CI: 10.0-14.6]), and a similar rate in extended wear (19.5 [95%CI:14.6-29.5]). Daily disposable lenses had a similar rate of infection to daily wear of hydrogel lenses (2.0 [95%CI:1.7-2.4]), but appeared to reduce the incidence of severe or vision loss keratitis (0.5 [95%CI: 0.5-0.6] and 0.0 [95%CI: 0.0-0.0] respectively). Conducting the study in New Zealand confirmed the increase in incidence for overnight use of lenses, irrespective of lens type. Comparison of the incidence rates in New Zealand and Australia show that the rates in the two countries are comparable, bar an unexplained lower rate of infection for extended wear of soft hydrogel lenses in New Zealand. Risk factors for infection were overnight use of lenses, from occasional overnight to extended wear use, poor lens case hygiene, smoking, high socio-economic status and less than 6 months experience in current lens type. Amongst daily wearers, Internet or mail order purchasing of lenses was also associated with a higher risk of infection. This study is unique in terms of the study design and sample size, and the wide scope of risk factors considered. The determination of these incidence rates of infection and identification of risk factors is of extreme value to lens wearers and lens care practitioners around the world, particularly as the strongest and most prevalent risk factors are modifiable.

Thesis (M.S.)--Marshall University, 2008. / Title from document title page. Includes abstract. Document formatted into pages: contains xiii, 126 p. Includes bibliographical references p. 113-118.

BACKGROUND: Fungal corneal ulcer is one of the major causes of visual impairment worldwide. Treatment of fungal corneal ulcer mainly depends on anti-fungal agents. In the current study, we developed an integrated combination therapy of cryotherapy and anti-fungal agents to facilitate effective treatment of fungal corneal ulcer. METHODS: Rabbit models of cornea infection were established using a combined method of intrastromal injection and keratoplasty. After treatment with cryotherapy and anti-fungal agents, scanning electron microscopy, transmission electron microscopy, and confocal microscopy were conducted to observe changes in microstructure in the rabbits. Periodic acid Schiff A and hematoxylin and eosin staining were used for detection of histological changes. RESULTS: Continuous scanning electron microscopy and transmission electron microscopy observations showed that cryothermal treatment inhibited growth of fungal mycelium by destroying fungal cellular structures. Typical cryotherapy was effective in curing fungal corneal ulcer. Different fungi showed different susceptibilities to treatment. The curative effect of Candida albicans was the best, while that of Aspergillus fumigates was the worst. CONCLUSIONS: Our study provides a novel method of a combination of cryotherapy and anti-fungal agents for treatment of fungal corneal ulcer. This treatment could help facilitate the practice of fungal keratitis treatment in the future.

Purpose: To investigate the immune responses in cornea, ocular draining lymph nodes and spleen as well as the priming site of HSV-specific lymphocytes and their possible role in HSK development. To explore the possible treatment of HSK by transplanting corneal allograft and collagen artificial cornea. Methods: BALB/c mice corneas were infected with RE strain HSV-1. Immunohistochemistry of eye sections was performed and flow cytometry was carried out for cell suspension of cornea, TG, submandibular ocular draining lymph node (SMDLN),a non-ocular related lymph node and spleen at various times post HSV-1 eye inoculation. Results: There were strong immune responses in ocular draining lymph nodes post HSV-1 ocular infection, with a significant increasing number of innate cells as well as B cells and T cells. These changes were not observed in non-ocular related lymph nodes or spleen. An antigen specific response to HSV-1 antigen stimulation was observed <i>in vitro</i> for crude cells from ocular draining lymph node and to a lesser extent for spleen, but no changes were observed for the cells from non-ocular related lymph node. Interestingly, removal of ocular draining lymph nodes or spleen prior to HSV inoculation did not prevent HSK, but adversely impaired the control of viral replication, which was indicated by severe blepharitis and encephalitis. Both corneal allograft and collagen artificial cornea failed to survive in HSK eye, and retro-corneal membrane and degradation were the main obstacles for artificial cornea. Conclusions: HSV-specific lymphocytes are primed mainly in ocular draining lymph nodes, however, these cells might not be necessarily required for HSK development. Prevention of retro-corneal membrane seems to be important for survival of both corneal allograft and artificial cornea in HSK eyes.

The proper organization and differentiation of the anterior segment is pivotal for normal eye development. Neural crest-derived POM cells are key contributors to correct anterior segment formation, differentiating to form the monolayered corneal endothelium. Mice with homozygous null mutations in the forkhead transcription factor gene, Foxc1, fail to develop a proper corneal endothelium stabilized by adherens junctions, with the endothelium adhering to the lens, preventing anterior chamber separation. The aim of this study was to evaluate the interaction between Foxc1 and the adherens junction protein, N-cadherin, as well as an associated gene, Msx1, during key stages in corneal endothelium development. Foxc1 was over-expressed in E12.5 and E13.5 POM cells and qPCR was carried out to determine the effect of Foxc1 on N-cadherin and Msx1 gene expression. Data showed over-expression of Foxc1 in wildtype E12.5 and E13.5 POM cells to cause significant fluctuations in N-cadherin and Msx1 expression (p < 0.05). POM cells were then transfected with a Foxc1 knock-down plasmid or the Foxc1 overexpression plasmid to evaluate the effect of Foxc1 on N-cadherin protein expression by Western blot analysis, however, these results were inconsistent with the gene expression analyses with no significant differences in N-cadherin expression detected. N-cadherin protein expression and localization was then further assessed by means of immunocytochemistry (ICC) and confocal microscopy in monolayer and hanging-drop POM cell cultures. Both qPCR and confocal microscopy data showed consistency, indicating increased amounts of N-cadherin in E12.5 cells relative to E13.5 cells, with membrane-bound N-cadherin showing a clear lattice-work pattern in hanging drop culture. Foxc1 over-expression/knock-down studies on E12.5 and E13.5 POM cells together suggest that N-cadherin is transcriptionally regulated by Foxc1 and that Foxc1 has a threshold level at which it is able to exert control over N-cadherin in POM cells. Foxc1 expression is therefore essential in establishing N-cadherin adhesion junctions in the corneal endothelium. Preliminary data also suggests that Msx1 may directly interact with Foxc1 in POM cells, however, further studies must be undertaken to verify and establish the effects of Foxc1/N-cadherin/ Msx1 interaction in the development of a cohesive, integrated corneal endothelium and functional anterior segment. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Zugl.: Berlin, Freie Universiẗat, Diss., 2008.

Thesis (Ph.D.)--Aberdeen University, 2009. / Includes bibliographical references.

Submitted in partial fulfillment for the Degree of Master of Technology: Biological Sciences at M.L. Technikon, 2001. / Mycotic keratitis has been found to account for 6% to 50% of all cases of ulcerated keratitis. Fusarium species, and in particular Fusarium so/ani, is the most frequent cause of mycotic infections of the cornea. These infections lead to a marked loss of vision and eventually a complete perforation of the cornea if not correctly diagnosed and treated. Fusarium species produce toxic mycotoxins that are known to exert adverse health effects in humans and animals. However, very few attempts have been made to establish the mycotoxin-producing capabilities of clinical isolates of Fusarium species from keratitis infections or any other human infections for that matter. / M

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