No description available.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1978. / Bibliography: leaves 170-172. / Microfiche. / xi, 172 leaves ill

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.

No description available.

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 (doctoral)--Universität Mainz.

No description available.

No description available.

Abstract A population-based study to investigate the epidemiological, genetic and clinical features of neurofibromatoses (NF) in Northern Finland was carried out between 1989–1996. The area concerned was that served by Oulu University Hospital, with a total population of 733 037. A total of 197 patients with neurofibromatosis type 1 (NF1), five with neurofibromatosis type 2 (NF2) and eight with segmental neurofibromatosis (NF5) fulfilling the diagnostic criteria were identified among several hundred patients examined on account of a possible NF diagnosis. The 197 NF1 patients came from 119 families. 77 of these cases were sporadic, 117 familial, and three were mothers of children suffering from NF1 who were themselves diagnosed as having segmental NF. The male/female ratio was 0.93 (95 males and 105 females). The geographical distribution of the patients roughly corresponded to that of the general population in the area. The overall prevalence of NF1 was 23/100 000, with a peak prevalence of 34/100 000 in the age group 10 to 19 years. The overall birth incidence of NF1 was estimated to be 27/100 000, with the highest figure, 37/100 000, recorded in the six-year period 1990–1995. The mean age at the time of diagnosis was 20 ± 16 years in the whole population and 6 ± 4 years in the children born in the 1980's. A new mutation was suspected in 49% of the NF1 cases (96/197), and a mutation rate of 4.37 ± 0.72 × 10-5 was obtained for the period 1960–1995. The relative fitness of the NF1 patients was 0.48, being reduced more in the affected males (0.24) than in the females (0.72). The mean maternal and paternal ages of the sporadic patients were 30 ± 6 and 33 ± 6 years, respectively, which is significantly higher than in the general population. Two cases with a deletion of the NF1 gene were identified, one encompassing the loci from EVI-20 to INT-38 and the other the INT-27 locus, representing 3% of the 66 cases analysed. In seven familial cases the parental origin of the new mutation could be verified and linkage studies showed that the oldest affected individual in the family had inherited the mutation from the father in 6/7 cases. In one family seven members in three generations were affected with a rare spinal neurofibromatosis, and a linkage to the NF1 gene was shown. Of these seven patients, four are included among the 197 studied here while the other three lived outside the area. The diagnostic features of the 164 NF1 patients aged from three months to 73 years who were examined clinically included café au lait spots (CLS) in 96% of cases, freckles in 87%, neurofibromas in 69%, plexiform neurofibromas in 20%, Lisch nodules in 70%, optic glioma (asymptomatic) in 20% and pseudarthrosis in 3%. 56% of the cases had an affected first degree relative. A plexiform neurofibroma was diagnosed in 33 individuals and this became a malignant peripheral nerve sheath tumour(MPNST) during the seven years of monitoring in 15% of cases (5/33). Hyperintense T2 lesions in a MRI scan of the brain were found in 94% of the children under the age of six years who had had such a scan (n = 17) and in 84% of those under 16 years (n = 50). Symptoms related to NF1 which needed medical intervention, rehabilitation or follow-up were diagnosed in about 2/3 of the cases, and in 38% of cases such medical problems of this kind had been treated before NF1 was actually diagnosed. All these findings emphasise the need for a multidisciplinary approach to the follow-up of neurofibromatoses.

INTRODUCTION: Canada has yet to conduct high quality, prospective, population-based surveys that measure incident visual impairment, its risk factors, and adverse consequences, creating an unmet need to obtain more rigorous analysis in this regard QUESTIONS: What is the 3-year incidence of visual impairment in each province? What are the risk factors for the 3-year incidence of visual impairment? Do they include geographic, sociodemographic, lifestyle, social, health and healthcare factors? Does vision loss increase the odds of balance problems after three years? METHODS: Baseline and 3-year follow-up data were used from the Canadian Longitudinal Study on Aging. The Comprehensive Cohort included 30,097 adults ages 45-85 years old recruited from 11 sites across 7 provinces. Presenting binocular visual acuity was measured using the Early Treatment of Diabetic Retinopathy Study chart. Incidence of VI was defined as the development at follow-up of visual acuity worse than 20/40 in those with acuity better than or equal to 20/40 at baseline. Balance was measured using the one-leg balance test. Those who could not stand on one leg for at least 60 seconds were classified as having failed the test. Participants were asked about the self-report of a diagnosis of cataract, macular degeneration, or glaucoma. RESULTS: 3.88% (95% Confidence Interval (CI) 3.61, 4.17) of Canadian adults developed VI over a 3-year period. There was a high degree of variability in the incidence between Canadian provinces with a low of 1.42% in Manitoba and a high of 7.33% in Nova Scotia. Uncorrected refractive error was the leading cause of incident VI. Risk factors for incident VI included older age (odds ratio (OR)=1.07, 95% CI 1.06, 1.07), Black race (OR=2.64, 95% CI 1.36, 5.14), lower household income (OR=1.73 for those making less than $20,000 per year, 95% CI 1.24, 2.40), current smoking (OR=1.78, 95% CI 1.37, 2.32), and province. Of the 12,158 people who could stand for 60 seconds on one leg at baseline, 18% were unable to do the same at follow-up 3 years later. After adjustment for demographic and health variables, those with worse visual acuity (per 1 line) were more likely to fail the balance test at follow-up (OR=1.15, 95% CI 1.10, 1.20). Those with a report of a former (OR=1.59, 95% CI 1.17, 2.16) or current cataract (OR=1.31, 95% CI 1.01, 1.68) were more likely to fail the test at follow-up. CONCLUSION: The incidence of visual impairment is common in older Canadian adults, varies markedly between provinces, and is largely due to treatable causes. Risk factors for VI suggest sub-groups that may benefit from interventions to improve access to eye care. These data provide longitudinal evidence that vision loss increases the odds of balance problems over a 3-year period. Efforts to prevent avoidable vision loss are needed as are efforts to improve the balance of visually impaired people.