Biomedical subjects

Nigel Morlet

Publications and source records attributed to Nigel Morlet.

8 recordsLinked to original sources

PubMed2006

Cataract surgery practice and endophthalmitis prevention by Australian and New Zealand ophthalmologists.

PURPOSE: Our aim was to examine current cataract surgery practice and the methods of chemoprophylaxis used in Australia and New Zealand, and to determine if these factors were related to self-reported incidence rates of postoperative endophthalmitis. METHODS: All Fellows and trainees of the Royal Australian and New Zealand College of Ophthalmologists were surveyed about their cataract surgery practices and methods of chemoprophylaxis for the prevention of postoperative endophthalmitis. Associations between self-reported incidence rates of endophthalmitis and clinical practice were examined using multivariate Poisson regression modelling. RESULTS: There were 731 respondents (81.6% of 896 surveyed) to the survey. Respondents reported a total of 162,120 cataract operations and 92 cases of endophthalmitis in 2003, a cumulative incidence of 0.057%. The self-reported incidence of endophthalmitis varied from 0.034% in Victoria to 0.56% in the Northern Territory. Topical antibiotics were used preoperatively by 46.7% compared with 97.4% postoperatively; while only 44.1% used subconjunctival antibiotics. The routine use of subconjunctival antibiotic halved the self-reported incidence of postoperative endophthalmitis (incidence rate ratio 0.53, 95% confidence interval 0.30-0.92). CONCLUSIONS: Subconjunctival antibiotics may be beneficial in the prevention of endophthalmitis after cataract surgery.

Anti-Bacterial Agents↗

PubMed2005

Management and outcomes of postoperative endophthalmitis since the endophthalmitis vitrectomy study: the Endophthalmitis Population Study of Western Australia (EPSWA)'s fifth report.

PURPOSE: To examine if changes in the diagnosis and management of postoperative endophthalmitis have occurred since 1995, and to identify factors that might predict final visual outcome. DESIGN: Retrospective, population-based, noncomparative, consecutive case series. PARTICIPANTS: Patients with clinically diagnosed endophthalmitis after cataract surgery and lens-related surgery in Western Australia from 1980 to 2000. METHODS: Endophthalmitis cases were identified using record linkage and cross-referencing with the surgical logbooks of vitreoretinal surgeons before validation by medical record review. MAIN OUTCOME MEASURES: Microbiological data (microorganisms isolated and antibiotic susceptibilities), diagnostic interventions, surgical procedures, therapeutic interventions, and visual acuity (VA). RESULTS: During the 21-year period, 213 episodes of endophthalmitis occurred after cataract surgery. Since 1995, both anterior chamber sampling and vitreous sampling have increased significantly. The overall use of vitrectomy has also increased, but we did not observe a difference according to presenting VA. Intravitreal antibiotic use increased significantly, whereas the use of both subconjunctival and IV antibiotics decreased. In one third of patients, the VA at least 6 months after admission for endophthalmitis was worse than 6/18. This was associated with treatment that did not include the use of oral antibiotics (odds ratio [OR], 3.86; 95% confidence interval [CI], 1.21-12.39; P = 0.02), growth from intraocular samples of organisms other than coagulase-negative staphylococci (OR, 9.84; 95% CI, 2.84-34.09; P<0.001), and a discharge VA worse than 6/18 (OR, 6.10; 95% CI, 1.63-22.89; P = 0.01). CONCLUSIONS: Although we observed noticeable changes in the diagnosis and management of endophthalmitis since 1995, visual outcomes have not improved and remain poor. Our finding that treatment with oral antibiotics may be associated with a better visual outcome warrants further investigation.

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PubMed2004

Acanthamoeba keratitis: the role of domestic tap water contamination in the United Kingdom.

PURPOSE: The incidence of acanthamoeba keratitis (AK) in the UK is some 15 times that in the United States and seven times that in Holland. To investigate reasons for this higher frequency, a study of the role of domestic tap water as a potential source of AK was undertaken. METHODS: Tap outlets from the homes of 27 patients with culture-proven AK were sampled and cultured for free-living amoebae (FLA). For all Acanthamoeba isolates, mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) and cytochrome oxidase (cox 1/2) sequence typing was performed to determine the similarity between corneal and tap water isolates. RESULTS: FLA, including Acanthamoeba, were isolated from 24 (89%) of 27 homes, and the presence within the homes varied significantly with tap water temperature and location: 19 (76%) of 25 bathroom sink cold taps sampled compared with 6 (24%) of 25 hot and 9 (47%) of 19 kitchen cold taps compared with 3 (16%) of 19 of hot kitchen taps. Acanthamoeba were isolated from 8 (30%) of 27 homes (five bathroom sink cold taps, one cloakroom cold tap, one bath, and one bedroom sink mixer [hot/cold] taps). In six cases, identical Acanthamoeba mtDNA profiles were found for the clinical and home tap water isolates. In keeping with UK plumbing practice, 24 of 27 homes had internal roof water storage tanks to supply domestic taps, but the mains fed the kitchen cold tap. CONCLUSIONS: Water storage tanks promote colonization of domestic water with FLA, including Acanthamoeba, and hence increase the risk of AK. This accounts for the significantly greater incidence of AK in the UK and supports advice to avoid using tap water in contact lens care routines.

Acanthamoeba↗

PubMed2004

Significant nonsurgical risk factors for endophthalmitis after cataract surgery: EPSWA fourth report.

PURPOSE: Endophthalmitis remains a devastating complication of cataract surgery, despite improved methods of prophylaxis and surgical technique. The current study was conducted to identify sociodemographic, environmental, and clinical risk factors for the development of postoperative endophthalmitis, using population-based administrative data from Western Australia. METHODS: The Western Australian Data Linkage System identified all patients who underwent cataract surgery, along with those in whom postoperative endophthalmitis subsequently developed, from 1980 to 2000 inclusive. Cases of endophthalmitis were cross-referenced with other sources and validated by medical record review. After selection and preliminary analysis of potential risk factors, multivariate logistic regression modeling was used to estimate odds ratios for the selected variables. RESULTS: Over the 21 years, 210 cases of endophthalmitis occurred after 117,083 cataract procedures, yielding a cumulative incidence rate of 1.79 per 1000 procedures. The incidence of endophthalmitis decreased for extracapsular extraction over the whole period, but not for phacoemulsification over the recent 12 years. There was no risk-adjusted difference in the incidence rate of endophthalmitis for the various cataract surgery procedure types. However, a significantly higher risk was found in patients aged over 80 years, in having surgery in private hospitals, and to a lesser degree in having same-day surgery and surgery in winter. Cataract surgery with lacrimal or eyelid procedures dramatically increased the risk of endophthalmitis. CONCLUSIONS: It may be possible to reduce the incidence rate of postoperative endophthalmitis by almost 80% with a systematic approach to the management of elderly patients, hospital stay, and clinical protocols.

Age Factors↗

PubMed2003

Trends in cataract surgery and postoperative endophthalmitis in Western Australia (1980-1998): the Endophthalmitis Population Study of Western Australia.

OBJECTIVES: Postoperative endophthalmitis results from an intraocular infection and usually occurs following cataract surgery. It has significant morbidity and causes severe visual impairment or blindness of the eye. The aim of this study was to assess the trends in the incidence rates of cataract surgery and postoperative endophthalmitis in Western Australia for the period 1980-1998. METHODS: The Western Australian Record Linkage Project was used to link the morbidity records for all patients treated for cataract surgery in Western Australia in 1980-1998. Patient records were selected using the international classification for diagnosis and procedure codes pertaining to cataract surgery and postoperative endophthalmitis. All cases of postoperative endophthalmitis were validated by case-note review. The separate databases of the Royal Perth Hospital microbiology and anaesthetic departments as well as the vitreo-retinal surgeon logbooks were used to cross-validate the hospital morbidity database. Trends in the incidence rates of cataract surgery and postoperative endophthalmitis were assessed by Poisson regression. RESULTS: There were 94,653 cataract procedures performed for 63,007 patients in Western Australia during the 19-year period. The majority (88%) of cataract procedures performed were in patients aged 60 years or older. Postoperative endophthalmitis developed in 188 patients, with serious visual impairment occurring in 70.6% of patients for whom visual acuity data was available at presentation. The incidence rate of cataract surgery increased more than three-fold from 1981 (102 per 100,000 person years) to 1998 (345 per 100,000 person years), mainly due to the increase in extracapsular cataract extraction during the 1980s and phacoemulsification extraction from 1990 onwards. In contrast, the average annual incidence rate of postoperative endophthalmitis remained relatively unchanged at around 2 per 1000 cataract procedures over the same period. CONCLUSION: Cataract surgery is becoming more prevalent in the elderly as the life expectancy of the population increases. There has been a dramatic shift in surgical practice during the last 30 years with small-incision phacoemulsification being the predominant method of intervention used since 1990. Despite changes in surgical practice the incidence rate of postoperative endophthalmitis has remained the same.

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PubMed2003

Coding accuracy for endophthalmitis diagnosis and cataract procedures in Western Australia. The Endophthalmitis Population Study of Western Australia (EPSWA): second report.

As an initial phase of the Endophthalmitis Population Study of Western Australia (EPSWA), this paper reports the results from an intensive comparative validation of all possible surgery-related endophthalmitis cases identified for the period from 1980 to June 1999 from the Hospital Morbidity Data System (HMDS) of the WA Record Linkage Project with external sources. The external sources were the microbiology and anaesthetic databases from Royal Perth Hospital (where most of the cases of endophthalmitis were treated) and surgeon logbooks of two vitreoretinal surgeons treating endophthalmitis in Perth over the study period. As it was discovered that a large proportion of all cases coded with endophthalmitis did not have any ocular surgery, the validation also included a sample from these cases. The purpose of validating these cases was to ensure that our count of post-operative endophthalmitis had not excluded any cases whose surgery might not have been recorded in the HMDS database. It was also intended to provide an estimate of all miscoded endophthalmitis cases as a first step towards future improvement of coding accuracy. Since we suspected that phaco-emulsification was under-coded, we also examined a sample of cataract procedures. Of all surgery-related endophthalmitis cases coded in the HMDS, only 50.9% (274 of 538) were found to be valid cases. External sources identified 83 cases of endophthalmitis, 49 did not have endophthal-mitis codes but were in the HMDS file with an associated code. Of the remaining externally identified cases, 13 were missing altogether from the HMDS file, 7 of which were correctly coded in the notes while the other 6 were coded with associated codes, and 21 were diagnosed after the date the HMDS file was extracted. The validation of a random sample of the non-surgery-related cases coded with endophthalmitis suggested that the vast majority of them were miscoded (88%, 139 of 158 sampled from 1474 cases). The systematic coding errors reported in this paper may be attributed to both the clinical and the coding departments of the hospital. In any case, coding inaccuracy itself is a serious concern for data quality of any linked database systems and for epidemiological researchers using such data. The increased use of aggregated data in epidemiological research further underscores the importance of coding accuracy and thus data validation. The use of external sources for case identification and case validation are two ways of ensuring data completeness/quality and validity of results.

Cataract↗

PubMed2002

Endophthalmitis.

Australia and New Zealand continue to be at the forefront of endophthalmitis research. In this Clinical Controversy, an ophthalmologist from each country presents different approaches to the management of a 72-year-old patient with routine endophthalmitis following cataract surgery. Mark Elder concludes that this case needs aqueous and vitreous aspirates for culture and the initial treatment of choice is intracameral vancomycin and amikacin. The evidence for intravitreal steroids is equivocal. Systemic antibiotics are indicated if there is a possibility of a bacterial biofilm present on the intraocular lens. Nigel Morlet concludes that timely intervention with appropriate antibiotics delivered in the right concentration to the vitreous cavity is the crux of successful management of endophthalmitis. Aggressive treatment of the inflammatory response is also required to further reduce the damage to the intraocular structures. Both ophthalmologists agree that vitrectomy is not necessarily the most appropriate treatment option.

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PubMedDate not supplied

Socioeconomic and rural differences for cataract surgery in Western Australia.

BACKGROUND: To examine the relationship between socioeconomic factors, residential locality and cataract surgery incidence. METHODS: This was a population-based study using the Western Australian Data Linkage System to identify all cataract operations performed in patients aged 50+ years in 1996 and 2001. Patients' residential addresses at the time of operation were geocoded to census localities. Using census-derived indices, procedures were categorized into socioeconomic groups and residential locations (metropolitan and rural). Poisson regression was used to analyse for differences in procedure rates. RESULTS: The crude cataract surgery rate in Western Australia increased from 4458 to 6631 procedures per million person-years between 1996 and 2001. Female and older patients underwent more surgery. Metropolitan residents were more likely to undergo surgery compared with rural residents; a difference that increased by 17% between 1996 and 2001 (1996: incidence rate ratio [IRR] 1.07, 95% confidence interval [CI] 1.02-1.13; 2001: IRR 1.24, 95% CI 1.18-1.29). A pronounced 'U-shaped' pattern of difference had developed for socioeconomic disadvantage by 2001. The most advantaged underwent 9% more surgery than the most disadvantaged. Rates in the middle two groups were less than the lowest one. CONCLUSION: There was growing inequity in the rates of cataract surgery for rural and poorer patients between 1996 and 2001. These differences partly reflect the increasingly two-tiered Australian health system with more privately provided cataract surgery in urban areas.

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