Ophthalmology (Eye & Ear Hospital) - Research Publications
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ItemVision impairment predicts 5 year mortality(BMJ PUBLISHING GROUP, 2001-03)AIM: 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 3271 participants, 231 (7.1%) were reported to have died in the intervening 5 years. Of the remaining 3040 participants eligible to return for follow up examinations, 2594 (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 (OR=2.34) was associated with a significantly increased risk of mortality, as were increasing age (OR=1.09), male sex (OR=1.62), increased duration of cigarette smoking (OR=2.06 for smoking >30 years), increased duration of hypertension (OR=1.51 for duration >10 years), and arthritis (OR=1.42). CONCLUSIONS: Even mild visual impairment increases the risk of death more than twofold. Further research is needed to determine why decreased visual acuity is associated with increased risk of mortality.
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ItemVision impairment and older drivers: who's driving?(BRITISH MED JOURNAL PUBL GROUP, 2002-10)AIM: To establish the association between impaired vision and drivers' decisions to stop driving, voluntarily restrict driving, and motor vehicle accidents. METHODS: Driving related questions were included in a population based study that determined the prevalence and incidence of eye disease. Stratified random cluster samples based on census collector districts were selected from the Melbourne Statistical Division. Eligible participants aged 44 years and over were interviewed and underwent a comprehensive ophthalmic examination. The outcomes of interest were the decision to stop driving, limiting driving in specified conditions, and driving accidents. The associations between these outcomes and the legally prescribed visual acuity (<6/12) for a driver's licence were investigated. RESULTS: The mean age of the 2594/3040 (85%) eligible participants was 62.5 (range 44-101). People with visual acuity less than 6/12 were no more likely to have an accident than those with better vision (chi(2) = 0.175, p>0.9). Older drivers with impaired vision, more so than younger adults, restrict their driving in visually demanding situations (p<0.05). Of the current drivers, 2.6% have vision less than that required to obtain a driver's licence. The risk of having an accident increased with distance driven (OR 2.57, CL 1.63, 4.04 for distance >31 000 km) but not with age. CONCLUSION: There was no greater likelihood of self reported driving accidents for drivers with impaired vision than those with good vision. While many older drivers with impaired vision limit their driving in adverse conditions and some drivers with impaired vision stop driving, there are a significant number of current drivers with impaired vision.
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ItemUtilisation of eye care services by urban and rural Australians(BMJ PUBLISHING GROUP, 2002-01)AIM: To investigate factors related to the use of eye care services in Australia. METHODS: Health, eye care service use, and sociodemographic data were collected in a structured interview of participants in a population based study. All participants had a standard eye examination. RESULTS: Men (OR 1.3 CL 1.02, 1.7), those who spoke Greek (OR 2.1 CL 1.1, 3.8) or Italian (OR 1.9 CL 1.0, 3.3), and those without private health insurance (OR 1.59 CL 1.22, 2.04) were more likely to have not used eye care services. Ophthalmology services were utilised at lower rates in rural areas (OR 0.14 CL 0.09, 0.2). Approximately 40% of participants with undercorrected refractive error, cataract, and undiagnosed glaucoma had seen either an ophthalmologist, optometrist, or both within the last year. CONCLUSION: Despite the similarity in prevalence of eye disease in urban and rural areas, significant differences exist in the utilisation of eye care services. Sex, private health insurance, urban residence, and the ability to converse in English were significant factors associated with eye healthcare service use. Many participants had undiagnosed eye disease despite having seen an eye care provider in the last year.
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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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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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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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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.
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ItemIntraocular pressure before and after cataract surgery in participants of the Melbourne Visual Impairment Project( 2001)The purpose of this study was to investigate the effect of cataract surgery on intraocular pressure (IOP) in a cluster stratified random sample of the population of Victoria, Australia. A total of 3271 participants aged 40 years or older were examined at baseline for the Visual Impairment Project. The baseline study (1992-1994) was followed by a 5-year incidence study. The IOP data were compared between participants who had cataract surgery between the two stages of the study and participants with and without cataract at follow up. The IOP was also compared before and after cataract extraction in glaucoma participants. An eligible 89 non-glaucoma and 24 glaucoma participants had cataract surgery between the two time points. The analyses showed that IOP increases with age in non-operated eyes in both glaucoma and non-glaucoma groups. However, IOP decreased significantly after cataract surgery in eyes with glaucoma but did not change significantly in non-glaucoma participants.
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ItemCause-specific prevalence of bilateral visual impairment in Victoria, Australia: the Visual Impairment Project(Elsevier (Initially -American Academy of Ophthalmology), 2001)Purpose: To study the cause-specific prevalence of eye diseases causing bilateral visual impairment in Australian adults. Design: Two-site, population-based cross-sectional study. Participants: Participants were aged 40 years and older and resident in their homes at the time of recruitment for the study. The study was conducted during 1992 through 1996. Methods: The study uses a cluster stratified random sample of 4744 participants from two cohorts, urban, and rural Victoria. Participants completed a standardized interview and eye examination, including presenting and best-corrected visual acuity, visual fields, and dilated ocular examination. The major cause of vision loss was identified for all participants found to be visually impaired. Population-based prevalence estimates are weighted to reflect the age and gender distribution of the two cohorts in Victoria. Main Outcome Measures: Visual impairment was defined by four levels of severity on the basis of best-corrected visual acuity or visual field: <6/18 ≥6/60 and/or <20° ≥10° radius field, moderate vision impairment; severe vision impairment, <6/60 ≥3/60 and/or <10° ≥5° radius field; and profound vision impairment <3/60 and/or <5° radius field. In addition, less-than-legal driving vision, <6/12 ≥6/18, and/or homonymous hemianopia were defined as mild vision impairment. In Australia, legal blindness includes severe and profound vision impairment. Results: The population-weighted prevalence of diseases causing less-than-legal driving or worse impairment in the better eye was 42.48/1000 (95% confidence interval [CI), 30.11,54.86). Uncorrected refractive error was the most frequent cause of bilateral vision impairment, 24.68/1000 (95% CI, 16.12, 33.25), followed by age-related macular degeneration (AMD), 3.86/1000 (95% CI, 2.17,5.55); other retinal diseases, 2.91/1000 (95% CI, 0.74, 5.08); other disorders, 2.80/1000 (95% CI, 1.17,4.43); cataract, 2.57/1000 (95% CI, 1.38, 3.76); glaucoma, 2.32/1000 (95% CI, 0.72, 3.92); neuro-ophthalmic disorders, 1.80/1000 (95% CI, 0, 4.11); and diabetic retinopathy, 1.53/1000 (95% CI, 0.71,2.36). The prevalence of legal blindness was 5.30/1000 (95% CI, 3.24, 7.36). Although not significantly different, the causes of legal blindness were uncorrected refractive errors, AMD, glaucoma, other retinal conditions, and other diseases. Conclusions: Significant reduction of visual impairment may be attained with the application of current knowledge in refractive errors, diabetes mellitus, cataract, and glaucoma. Although easily preventable, uncorrected refractive error remains a major cause of vision impairment.
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ItemAssociation of demographic, familial, medical, and ocular factors with intraocular pressure(American Medical Association, 2001)Objective: To describe the distribution and associations of demographic, familial, medical, and ocular factors with intraocular pressure (lOP).Methods: A cluster stratified random sample of urban and rural residents of Victoria, Australia, aged 40 years and older. Participants completed an interview and underwent a standardized dilated ophthalmic examination including measurement of IOP with an electronic applanation tonometer (Tono-Pen). Glaucoma status (possible, probable, definite) was determined by a consensus panel. The main outcome measure was IOP.Results: The mean age of the 4576 participants was 59 years, 53% were women, 32% were born overseas, and 132 had open-angle glaucoma. Geometric mean (SD) IOP was 14.3 (± 1.5) mm Hg. The relationship between IOP and nuclear sclerosis, iris color, and family history of glaucoma depended on glaucoma status. In those with glaucoma, family history of glaucoma and country of birth were significantly associated with IOP in multivariate models (model: r²=0.08, P=0.01). In the group without glaucoma, place of residence, use of alcohol, iris color , vitamin E intake, and spherical equivalent were associated with IOP (model: r²=0.01, P=.006).Conclusion: In participants with glaucoma, genetic factors seem to be stronger predictors of IOP, whereas in those without glaucoma, lifestyle and physiological factors seem to play a greater role.