Ophthalmology (Eye & Ear Hospital) - Research Publications
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ItemVision impairment predicts five-year mortality(American Ophthalmological Society, 2000)Purpose: To describe predictors of mortality in the 5-year follow-up of the Melbourne Visual Impairment Project (VIP) cohort. Methods: The Melbourne VIP was a population-based study of the distribution and determinants of age-related eye disease in a cluster random sample of Melbourne residents aged 40 years and older. Baseline examinations were conducted between 1992 and 1994. In 1997, 5-year follow-up examinations of the original cohort commenced. Causes of death were obtained from the National Death Index for all reported deaths. Results: Of the original 3,271 participants, 231 (7.1%) were reported to have died in the intervening 5 years. Of the remaining 3,040 participants eligible to return for follow-up examinations, 2,594 (85% of eligible) did participate, 51 (2%) had moved interstate or overseas, 83 (3%) could not be traced, and 312 (10%) refused to participate. Best corrected visual acuity <6/12 and cortical cataract were associated with a significantly increased risk of mortality, as were increasing age, male sex, increased duration of cigarette smoking, increased duration of hypertension, and arthritis. Conclusions: Even mild visual impairment increases the risk of death more than twofold.
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ItemCholesterol-lowering medications reduce the risk of age-related maculopathy progression(Australasian Medical Publishing, 2001-09)Age-related macular degeneration (AMD) is the leading cause of blindness in elderly Australians. Currently, there are limited treatment options, and current research efforts are focused on determining the risk factors for AMD and developing effective treatment strategies. Some risk factors for cardiovascular disease have been shown to be associated with AMD, and one study has suggested that Alzheimer's disease is associated with age-related maculopathy. It has also been suggested that alleles of the apolipoprotein E (ApoE) gene may be associated with AMD, cardiovascular disease and Alzheimer's disease. Given this, it is interesting that statins - cholesterol-lowering medications - have been shown to decrease the risk of dementia and diabetes mellitus.
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ItemCataract : how much surgery do we have to do?(BMJ Publishing Group, 2000)How much cataract surgery do we have to do? When is enough enough? Around the world, this is a common question asked by governments, regional health authorities, health trusts, hospital managers, operating theatre staff, and ophthalmologists themselves. These are fair questions. The volume of cataract surgery already has increased dramatically around the world over the past 20 years. It increased approximately fourfold in just 10 years in both the United States and Sweden through the 1980s; and increased threefold in the United Kingdom over this time. In many areas cataract surgery now forms over half of all ophthalmic surgery, and in a number of countries cataract surgery has become the most common elective surgical procedure.
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ItemEpidemiology of pterygium in Victoria, Australia(BMJ Publishing Group, 2000-03)Aim: To describe the prevalence of and risk factors for pterygium in a population based sample of residents of the Australian state of Victoria who were aged 40 years and older.Methods:The strata comprised nine randomly selected clusters from the Melbourne statistical division, 14 nursing homes randomly selected from the nursing homes within a 5 kilometre radius of the nine Melbourne clusters, and four randomly selected clusters from rural Victoria. Pterygium was measured in millimetres from the tip to the middle of the base. During an interview, people were queried about previous ocular surgery, including surgical removal of pterygium, and their lifetime exposure to sunlight. Results: 5147 people participated. They ranged in age from 40 to 101 years and 2850 (55.4%) were female. Only one person in the Melbourne cohort reported previous pterygium surgery, and seven rural residents reported previous surgery; this information was unavailable for the nursing home residents. Pterygium was present upon clinical examination in 39 (1.2%) of the 3229 Melbourne residents who had the clinical examination, six (1.7%) of the nursing home residents, and 96 (6.7%) of the rural residents. The overall weighted population rate in the population was 2.83% (95% CL 2.35, 3.31). The independent risk factors for pterygium were found to be age (OR=1.23, 95% CL=1.06, 1.44), male sex (OR=2.02, 95% CL=1.35, 3.03), rural residence (OR=5.28, 95% CL=3.56, 7.84), and lifetime ocular sun exposure (OR=1.63, 95% CL=1.18, 2.25). The attributable risk of sunlight and pterygium was 43.6% (95% CL=42. 7,44.6). The result was the same when ocular UV-B exposure was substituted in the model for broad band sun exposure. Conclusion: Pterygium is a significant public health problem in rural areas, primarily as a result of ocular sun exposure.
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ItemDiabetic retinopathy in Victoria, Australia: the Visual Impairment Project(British Medical Association, 2000-08)Aim: To establish the prevalence, severity, and risk factors for diabetic retinopathy in a representative sample of Victorian residents aged 40 years and older.Methods: A population based, cluster sampling method was used to recruit 4744 participants (86% participation rate). Nine randomly selected, suburban Melbourne clusters and four randomly selected, rural Victorian clusters were used. Participants provided a detailed medical and personal history and underwent an ocular examination including funduscopy and fundus photography. Rural participants provided a blood sample, from which the glycosylated haemoglobin percentage was measured. The diagnosis of diabetic retinopathy was based on fundus photographs from participants with self reported diabetes.Results: The prevalence of diabetic retinopathy among people with self reported diabetes was 29.1%. The prevalence of untreated, vision threatening retinopathy was 2.8%. Retinopathy was positively associated with a longer reported duration of diabetes diagnosis (p<0.01) and with higher fractions of glycosylated haemoglobin (p<0.01). Retinopathy was not significantly associated with age, ethnicity, body mass index, glaucoma, myopia or intake of alcohol, tobacco, or aspirin (all p>0.05).Conclusions: Most people in Victoria with proliferative diabetic retinopathy or clinically significant macular oedema have received laser treatment. There remains however, a small but important group who have not received treatment and whose vision is threatened. People with diabetes should be encouraged to maintain strict glycaemic control and to undergo regular screening to delay or prevent the development of retinopathy.
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ItemCorrection of refractive error in the Victorian population: the feasibility of "off the shelf" spectacles(British Medical Association, 2001)Aims - To assess the feasibility of providing a stock of ready made spectacles for correction of refractive error in the general population. Methods - Data were collected in the Visual Impairment Project, a population based survey of Victorian residents aged 40 years or older in randomly selected urban and rural sample areas. This included a refractive eye examination and the proportion of subjects with hypermetropia, emmetropia (defined as -1.0 to +1.0D spherical equivalent), and myopia documented in the 40-60 year age group. Results - 2595 (54.8%) participants were aged between 40 and 60 years. Those with a best corrected visual acuity of less than 6/12, astigmatism of more than 1.25D, and anisometropia of more than 0.5D were excluded. 516 participants had refractive error which was deemed suitable for correction by “off the shelf” spectacles. This represents 19.9% of all participants between 40 and 60 years of age. Provision of spectacles in 0.5D increments would provide suitable stock spectacles for 85.5% of a -3.0 to +3.0D range or 89.2% of a -3.50 to +3.50D range. Conclusions - Ready made “off the shelf” spectacles could significantly alleviate visual morbidity due to refractive error in up to 20% of an urban population in Australia. This approach may also be useful in developing countries with poor access to optometric services.
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ItemThe prevalence of age-related maculopathy: the Visual Impairment Project(Elsevier, 2000-08)Purpose: To determine the prevalence of age-related maculopathy (ARM) lesions in residents of the state of Victoria, Australia. Design: Population-based cross-sectional study. Participants: Total of 5147 residential and institutionalized persons aged 40 years and older, living in Victoria. Methods: Participants were recruited through a cluster, stratified, random sampling from nine urban clusters and four rural clusters. The presence of ARM lesions was graded from color stereo fundus photographs as well as slit-lamp stereo biomicroscopy according to the International Classification and Grading System. Main Outcome Measures: The presence of ARM lesions. Results: The mean age of participants was 60.2 years, and 55% were females. Gradable fundus photographs were available for at least one eye in 4345 (92%) of the participants. The weighted prevalence of neovascular age-related macular degeneration (AMD) was 0.39% (95% confidence limits [CL] = 0.20, 0.58), atrophic AMD was 0.27% (95% CL = 0.04, 0.50), and total AMD was 0.68% (95% CL = 0.30, 1.1). Prevalence of AMD was strongly related to age (P<0.001). Prevalence of early ARM was 15.1% (95% CL = 13.7, 16.4). Large drusen, 125 µm or more, were present in 6.3% of the participants. There was a higher prevalence of soft distinct drusen (7.5%) than soft indistinct drusen (4.3%). Retinal pigmentary abnormalities were present in 8.2% (95% CL = 7.2, 9.2). The prevalence of large drusen, soft drusen, and pigmentary abnormalities increased with age (P < 0.001). Prevalence of retinal pigmentary abnormalities increased with increasing drusen size (P < 0.001). Soft indistinct drusen were more common in women aged 70 years or older (P < 0.001). Bilaterality of any ARM was strongly age related, and women appeared to have a higher risk of both bilateral early ARM and AMD. Conclusions: These data provide age- and gender-specific prevalence of ARM and its component lesions in an ethnically diverse Australian population. Early ARM and AMD prevalence rates increased sharply from ages 70 and 80 years, respectively, in all ethnic groups. These higher rates will continue to increase the importance of AMD as our population ages.
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ItemPrevalence and predictors of open-angle glaucoma : results from the Visual Impairment Project(Elsevier (American Academy of Ophthalmology), 2001-11)Purpose: To determine the prevalence and investigate predictors of open-angle glaucoma in Victoria, Australia Design: Two-site, population-based cross-sectional study. Participants: Permanent residents aged 40 years and older at recruitment from 1992 through 1996. Methods: A cluster-stratified random sample of 4744 participants from two cohorts, urban and rural, participated. Participants completed a standardized interview regarding demographic, lifestyle, and medical characteristics and a dilated eye examination including measurement of intraocular pressure, visual fields, cup-to-disc ratios, and paired stereo photography of the optic discs. A consensus panel of six ophthalmologists determined glaucoma diagnosis. Main Outcome Measure: Diagnosis of glaucoma (possible, probable, definite). Results: The prevalence of possible glaucoma cases was 1.2% (95% confidence interval [CI], 0.60, 1.7), of probable cases was 0.70% (95% CI, 0.39, 1.0), and of definite cases was 1.8% (95% CI, 1.4, 2.2). There was a significant increase in glaucoma prevalence with age across all definitions, but there was no difference in age-standardized rates between genders. A total of 60% of probable and definite glaucoma cases were undiagnosed before this study. Adjusted for age, the strongest risk factor for glaucoma was a positive family history of glaucoma (odds ratio, 3.1; 95% CI, 1.6, 5.3). Glaucoma patients who had not attended an eye care provider in the last 2 years were eight times (95% CI, 3.2, 20.4) more likely to have undiagnosed disease. Conclusions: These results support the importance of the genetic or familial basis of many glaucoma cases and highlight the need to develop appropriate techniques to screen for undiagnosed disease.
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ItemOperated and unoperated cataract in Australia(Blackwell Publishing, 2000)Purpose: To quantify the prevalence of cataract, the outcomes of cataract surgery and the factors related to unoperated cataract in Australia. Methods: Participants were recruited from the Visual Impairment Project: a cluster: stratified sample of more than 5000 Victorians aged 40 years and over At examination sites interviews, clinical examinations and lens photography were performed. Cataract was defined in participants who had had previous cataract surgery, cortical cataract greater than 4/16, nuclear greater than Wilmer standard 2, or posterior subcapsular greater than I mm. Results: The participant group comprised 3271 Melbourne residents,403 Melbourne nursing home residents and 1473 rural residents. The weighted rate of any cataract in Victoria was 21.5%. The overall weighted rate of prior cataract surgery was 3.79%. Two hundred and forty-nine eyes had had prior cataract surgery. Of these 249 procedures, 49 (20%) were aphakic, 6 (2.4%) had anterior chamber intraocular lenses and 194 (78%) had posterior chamber intraocular lenses. Two hundred and eleven of these operated eyes (85%) had best -corrected visual acuity of 6/12 or better, the legal requirement for a driver’s license. Twenty-seven (11%) had visual acuity of less than 6/18 (moderate vision impairment). Complications of cataract surgery caused reduced vision in four of the 27 eyes (15%), or 1.9% of operated eyes. Three of these four eyes had undergone intracapsular cataract extraction and the fourth eye had an opaque posterior capsule. No one had bilateral vision impairment as a result of cataract surgery. Surprisingly, no particular demographic factors (such as age, gender; rural residence, occupation, employment status, health insurance status, ethnicity) were related to the presence of unoperated cataract. Conclusions: Although the overall prevalence of cataract is quite high, no particular subgroup is systematically under-serviced in terms of cataract surgery. Overall, the results of cataract surgery are very good, with the majority of eyes achieving driving vision following cataract extraction.
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ItemRisk factors for age-related maculopathy: the Visual Impairment Project(American Medical Association, 2001-10)Objective: To describe the risk factors and associated population attributable risk for age-related maculopathy (ARM) and age-related macular degeneration (AMD) in Australians aged 40 years and older. Methods: Residents were recruited from 9 randomly selected urban clusters and 4 randomly selected rural clusters in Victoria, Australia. At locally established test sites, the following information was collected: visual acuity, medical and health history, lifetime sunlight exposure, dietary intake, and fundus photographs. Age-related maculopathy and AMD were graded from the fundus photographs using an international classification and grading system. Backwards logistic regression was used to identify the independent risk factors for ARM and AMD. Results: The participation rate was 83% (n=3271) among the urban residents and 92% (n=1473) among the rural residents. Gradable fundus photographs of either eye were available for 4345 (92%) of the 4744 participants. There were 656 cases of ARM, giving a weighted prevalence of 15.1% (95% confidence limit [ CL] , 13.8, 16.4 ); and there were 30 cases of AMD, giving a weighted prevalence of 0.69% (95% CL, 0.33, 1.03). In multiple logistic regression, the risk factors for AMD were as follows: age (odds ratio [OR], 1.23; 95% CL, 1.17, 1.29), smoked cigarettes for longer than 40 years (OR, 2.39; 95% CL, 1.02, 5.57), and ever taken angiotensin-convening enzyme inhibitors (OR, 3.26; 95% CL, 1.33,8.01 ). The magnitude of all of these risk factors was slightly less for ARM, and having ever taken blood cholesterol-lowering medications was also significant (OR, 1.67; 95% CL, 1.12, 2.47; P=.001). Conclusion: Smoking is the only modifiable risk factor for ARM and AMD, among the many environmental and systemic factors that were assessed.