Melbourne Visual Impairment Project Research Articles

Projected number of Australians with visual impairment in 2000 and 2030.

This study aimed to project population-based prevalence data associated with visual impairment, in order to estimate the number of affected older Australians (aged 50 or older) in the years 2000 and 2030. We used data from the Blue Mountains Eye Study (BMES) and Melbourne Visual Impairment Project (MVIP), together with Australian Bureau of Statistics population projections. Similar definitions for moderate (6/24-6/60 visual acuity) and severe (< 6/60 visual acuity) visual impairment were used. Combining age-standardized data, we estimated that in the year 2000, 38 820 (0.73%) and 25590 (0.48%) Australians aged 50 years or older will have moderate and severe visual impairment, respectively. By 2030, these rates will have more than doubled, to an estimated 85910 (0.92%) and 57930 (0.62%) Australians with moderate and severe visual impairment, respectively. Women aged 50 years or older will have a 1.8-fold and four-fold risk, respectively, of moderate and severe visual impairment compared to men. Visual impairment will affect an increasing proportion of older Australians, Newer approaches to therapy, rehabilitation and community support for persons with visual impairment will be needed to meet this challenge.

Ultraviolet light exposure as a risk factor for ocular melanoma in Queensland, Australia

The state of Queensland, Australia, has one of the highest incidences of cutaneous melanoma in the world; this has been linked to the high sun exposure of the mainly Caucasian population. The role of sun exposure in the development of ocular melanoma (melanoma of the conjunctiva, iris, ciliary body or choroid) remains unclear. A case-control study involving 125 patients with ocular melanoma treated between 1972 and 1996, and 375 age- and sex-matched controls (three for each patient) was performed. A standardised telephone questionnaire examining ultraviolet exposure and other potential risk factors was administered. Cumulative lifetime ocular ultraviolet B (UV-B) exposure was assessed using the Melbourne Visual Impairment Project instrument. Risk factors identified include personal history of melanoma of the skin (odds ratio [OR] 2.42, 95% confidence interval [CI] 0.88, 6.62) or other skin cancers (OR 1.52, CI 0.99, 2.35), and family history of ocu-lar melanoma (OR 6.89, CI 0.70, 67.38). Protective factors included olive or black skin (OR 0.72, CI 0.40, 1.31), brown iris colour (OR 0.89, CI 0.51, 1.54), high resistance to sunburn (OR 0.58, CI 0.26, 1.31), and wearing prescription glasses (OR 0.78, CI 0.48, 1.25). Sunglass wearing was not found to be protective. Cumulative lifetime ocular UV-B exposure was not found to be a risk factor for ocular melanoma. However, there were too few cases of conjunctival and iris melanoma for these to be analysed as separate sub-groups.

Schizophrenia, psychotropic medication, and cataract

Objective To compare the distribution of cataract types between psychiatric patients diagnosed with schizophrenia and the general population not exposed to psychotropic medication, and to compare cataract prevalence between users and nonusers of various psychotropic medications in the general community. Design Case-control. Participants A total of 151 (93%) eligible patients from a community mental health service and 3271 (83%) eligible residents from the Melbourne Visual Impairment Project (VIP) were examined. Main outcome measures All patients 40 years of age and older from a community mental health service and residents of nine randomly selected areas of Melbourne were eligible. Best-corrected distance visual acuity was determined using a 4-m logarithm of the minimum angle of resolution (LogMAR) chart. The presence of cataract was determined by photographs or slit-lamp examination using direct and indirect retroillumination. Anterior, cortical, nuclear, and posterior subcapsular cataracts were measured. Participants from the Melbourne VIP were classified as to whether they had taken benzodiazepams, phenothiazines, thioxanthenes, butyrophenols, tricyclic antidepressants, or monoamine oxidase inhibitors for at least 12 months during their lifetime. Results The distribution of cataract type varied between persons with and without schizophrenia. Anterior subcapsular (ASC) cataract was significantly more prevalent (26%) in participants with schizophrenia from the community mental health service than Melbourne VIP participants (0.2%) not exposed to psychotropic medication (chi-square, 1 degree of freedom = 605.5, P = 0.001). This remained significant after controlling for age (odds ratios = 250, 95% confidence interval = 83.3, 1000). The distribution of the age-related cataract was similar across all groups of psychotropic medication users with the exception of the phenothiazine users. They had less of all types of the age-related cataracts, despite being slightly older than the control group (mean age, 60.0 vs. 58.4, t test = 0.85, P = 0.40). However, only cortical cataract in the phenothiazine group was statistically lower (chi-square, 1 degree of freedom = 3.96, P = 0.047). Conclusion This study has identified the need to investigate whether other newer agents, especially high-potency medications, cause ASC opacities if a certain threshold of exposure to psychotropic medications must be attained to develop cataract, or if schizophrenia itself is associated with cataract formation.

The need for cataract surgery: projections based on lens opacity, visual acuity, and personal concern

AIMTo assess the projected needs for cataract surgery by lens opacity, visual acuity, and patient concern.METHODSData were collected as part of the Melbourne Visual Impairment Project, a population based study...

The epidemiology of dry eye in Melbourne, Australia

Objective To describe the epidemiology of dry eye in the adult population of Melbourne, Australia. Design A cross-sectional prevalence study. Participants Participants were recruited by a household census from two of nine clusters of the Melbourne Visual Impairment Project, a population-based study of age-related eye disease in the 40 and older age group of Melbourne, Australia. Nine hundred and twenty-six (82.3% of eligible) people participated; 433 (46.8%) were male. They ranged in age from 40 to 97 years, with a mean of 59.2 years. Main outcome measures Self-reported symptoms of dry eye were elicited by an interviewer-administered questionnaire. Four objective assessments of dry eye were made: Schirmer’s test, tear film breakup time, rose bengal staining, and fluorescein corneal staining. A standardized clinical slit-lamp examination was performed on all participants. Dry eye for the individual signs or symptoms was defined as: rose bengal > 3, Schirmers < 8, tear film breakup time < 8, > 1 3 fluorescein staining, and severe symptoms (3 on a scale of 0 to 3). Results Dry eye was diagnosed as follows: 10.8% by rose bengal, 16.3% by Schirmer’s test, 8.6% by tear film breakup time, 1.5% by fluorescein staining, 7.4% with two or more signs, and 5.5% with any severe symptom not attributed to hay fever. Women were more likely to report severe symptoms of dry eye (odds ratio [OR] = 1.85; 95% confidence limits [CL] = 1.01, 3.41). Risk factors for two or more signs of dry eye include age (OR = 1.04; 95% CL = 1.01, 1.06), and self-report of arthritis (OR = 3.27; 95% CL = 1.74, 6.17). These results were not changed after excluding the 21 people (2.27%) who wore contact lenses. Conclusions These are the first reported population-based data of dry eye in Australia. The prevalence of dry eye varies by sign and symptom.

Use of eye care services by people with diabetes: the Melbourne Visual Impairment Project

AIMThe use of eye care services by people with and without diabetes was investigated in the Melbourne Visual Impairment Project (VIP), a population based study of eye disease in a...

The prevalence of glaucoma in the melbourne visual impairment project

Purpose The purpose of the study was to determine the prevalence of glaucoma in Melbourne, Australia. Methods All subjects were participants in the Melbourne Visual Impairment Project (Melbourne VIP), a population-based prevalence study of eye disease that included residential and nursing home populations. Each participant underwent a standardized eye examination, which included a Humphrey Visual Field test, applanation tonometry, fundus examination including fundal photographs, and a medical history interview. Glaucoma status was determined by a masked assessment and consensus adjudication of visual fields, optic disc photographs, intraocular pressure, and glaucoma history. Results A total of 3271 persons (83% response rate) participated in the residential Melbourne VIP. The overall prevalence rate of definite primary open-angle glaucoma in the residential population was 1.7% (95% confidence limits = 1.21, 2.21). Of these, 50% had not been diagnosed previously. Only two persons (0.1%) had primary angle-closure glaucoma and six persons (0.2%) had secondary glaucoma. The prevalence of glaucoma increased steadily with age from 0.1% at ages 40 to 49 years to 9.7% in persons aged 80 to 89 years. There was no relationship with gender. The authors examined 403 (90.2% response rate) nursing home residents. The age standardized rate for this component was 2.36% (95% confidence limits = 0, 4.88). Conclusion The rate of glaucoma in Melbourne rises significantly with age. With only half of patients being diagnosed, glaucoma is a major eye health problem and will become increasingly important as the population ages.

Methods for the Hong Kong Vision Study: a pilot assessment of visual impairment in adults

Introduction. The Hong Kong Vision Study (HKVS) was a pilot study to collect data on the prevalence of eye diseases and risk factors in Hong Kong using methodology comparable to that developed in America and Australia. Aim. The main goal was: to evaluate the application of the methodology in a different culture and language; and to determine the prevalence and risk factors of eye diseases in order to design a larger study of an ethnic Chinese population. Method. This study was patterned after the Melbourne Visual Impairment Project using the Chinese language in data collection and examinations. Conclusion. Well-designed methodology is transferable to different cultures, languages and continents. Use of similar methodology will enable better comparisons and analyses to be made from population-based data.

Visual impairment and socioeconomic factors

BACKGROUNDInformation about socio economic factors associated with visual impairment can assist in the design of intervention programmes. Such information was collected by the Melbourne Visual Impairment Project (Melbourne VIP).METHODSThe Melbourne...

Visual Impairment in Australia: Distance Visual Acuity, Near Vision, and Visual Field Findings of the Melbourne Visual Impairment Project

To describe the age-specific and gender-specific rates of blindness and visual impairment in urban adults aged 40 years and older. A population-based sample of residents was recruited. Presenting and best-corrected distance visual acuities were assessed. Functional near vision was measured at each participant's preferred distance. Visual field examination was performed with a Humphrey Field Analyzer (HFA); those unable to perform the field analyzer test attempted a Bjerrum screen or confrontation field. The study population comprised 3,271 residents (83% of eligible) from ages 40 to 98 years; 54% were women. Overall, 56% of the study population wore distance correction; this was significantly lower in men but higher in the older age groups. Age-adjusted rates of blindness were 0.066% in men and 0.170% in women. Vision with current correction improved after refraction by gender and age. Direct age-standardized rates of functional near vision did not vary significantly by gender. Forty-six people had significant visual field loss in their better eye. The proportion of participants with constriction of the visual field to within 20 degrees of fixation was similar for men and women when controlled for age (odds ratio, 0.81; 95% confidence interval, 0.44 to 1.49) but increased significantly with age controlled for gender. Visual field abnormalities were detected in 548 right eyes (17%) and 533 left eyes (16%). Although overall rates of blindness because of visual acuity loss were relatively low, nearly three times more people had visual impairment because of visual field loss than visual acuity loss. These results highlight the need to target blindness prevention programs to the aging population, with a special emphasis on women.

A comparison of participants with non-participants in a population-based epidemiologic study: The Melbourne Visual Impairment Project

Purpose: Adequate participation in population-based studies is essential to ensure that the sample is representative of the population under investigation. Participants may differ from non-participants on important variables such as age, sex, socioeconomic status, and general health factors. The Melbourne Visual Impairment Project (Melbourne VIP) is a population-based study designed to increase understanding of the prevalence and severity of common ocular disorders affecting people 40 years of age and over. Aim: The aim of this study was to determine the potential for any non-response bias by comparing data from participants and non-participants of the Melbourne VIP.Methods: Specific demographic and general variables were compared between the two groups. The variables included age, sex, education level, and social status. The reason for non-attendance was also recorded.Results: A total of 3271 (83%) eligible residents from the 9 sample areas were screened; 46% males and 54% females. Language spoken at home was significantly associated with participation. Residents whose main language at home was not English were less likely to attend the screening centre. (OR: 0.60; CI: 0.44–0.81). The main reasons given for non-attendance by eligible residents were lack of interest (6%), too busy to attend (4%), personal illness (2%), and attend own eye specialist (2%).Conclusion: We believe these results will not impact significantly on the interpretation of gender and age-specific data from the Melbourne VIP.

Reliability of a food frequency questionnaire to assess dietary antioxidant intake

OBJECTIVE Epidemiologic evidence of a role for antioxidants in the prevention of chronic disease has been inconclusive, in part due to the difficulty of measuring past diets of free-living populations. The purpose of the current study was to examine the reliability of a 19-item, self-administered, semiquantitative, food frequency questionnaire to assess intake of the major dietary antioxidants.METHODS Reliability was established by administering the food frequency questionnaire a second time by telephone. The subjects comprised 151 participants in the Melbourne Visual Impairment Project, a study of the distribution and determinants of eye disease in Melbourne residents aged 40 and over.RESULTS Spearman correlation coefficients ranged from 0.39 for spinach to 0.76 for yoghurt, and all were highly significant (all p=0.001). The reliability of the instrument was not influenced by gender, English speaking ability, or the number of days between the first and second administration of the questionnaire.CONCLUSION In conclusion, we have shown this 19-item food frequency questionnaire to be highly reliable. It should be useful for anyone involved in the study of the relationship of dietary antioxidant intake to health outcomes in large populations where limitations of time and money prohibit the collection of more detailed dietary intake information.

Diabetic retinopathy: examination practices and referral patterns of general practitioners.

To investigate general practitioners' (GPs') examination and referral practices for diabetic retinopathy. A questionnaire survey of a random stratified sample of 500 Victorian GPs. The response rate was 88%. 53% of GPs examined none or less than half of their patients with diabetes for diabetic retinopathy. Those who did examine for retinopathy rarely performed funduscopy through a dilated pupil and 65% reported that they never did. Only 37% had dilating drops in their surgery. Only 45% often or always tested visual acuity. 88% often or always referred patients at the recommended frequency to an ophthalmologist. Although most GPs do not perform dilated fundus examinations, they report referring their patients with diabetes for assessment by an ophthalmologist at an early stage to prevent vision loss. Referral chain breakdown may explain the discrepancy between GPs' reported referral rates and the lower rates of ophthalmic examination reported in the Melbourne Visual Impairment Project.

Cost‐effectiveness of recruitment methods in a population‐based epidemiological study: the Melbourne Visual Impairment Project

The cost-effectiveness of five recruitment methods was evaluated to determine the best method of encouraging eligible persons to participate in the Melbourne Visual Impairment Project (a population-based epidemiological study). The evaluation was divided into two phases. Phase 1 included one of two types of initial contact, by direct personal contact or by telephone. Phase 2 involved recruiting residents after an attempt had been made by either the telephone or the doorstep approach, and included a second attempt by a field interviewer, subsequent attempts by senior field staff, and finally, financial incentives. The cost-effectiveness of each method was determined by dividing the approach's cost by the effectiveness ratio. We identified 269 eligible households with 356 eligible residents. An 89 per cent response rate was achieved at the examination centre, comprising 61 per cent from Phase 1 and 28 per cent from Phase 2. Although both recruitment methods in Phase 1 were equally cost-effective, there was a significant difference in the effectiveness of each method in actually recruiting residents. The doorstep method was more costly per attender but was far more effective at 76 per cent recruitment than the telephone method at 47 per cent (P < 0.001). We have demonstrated a practical two-stage approach (the doorstep method in Phase 1 and follow-up strategies in Phase 2) to population-based recruitment involving the middle to elderly age group that should be relevant to many epidemiological studies.

Methods for a population-based study of eye disease: the Melbourne Visual Impairment Project.

The methodology of the Melbourne Visual Impairment Project, a major population-based survey of eye disease on 3,500 randomly selected individuals aged 40 years of age and over in the Melbourne metropolitan region, is presented. The aims of the study are to determine the distribution and determinants of eye disease in an urban population; the impact of eye disease on visual function and the activities of daily living; and the accessibility of eye health care services in the community. All procedures are conducted according to a standardised protocol to allow for comparison with other population-based studies, both in Australia and overseas. Information collected from this study will be employed in the development of recommendations related to eye health care service delivery and establishment of priorities for future public education programmes and health research.

Myocardial ischaemia and defects of atrioventricular conduction associated with cardiac surgery.

<h3>BACKGROUND</h3> Information about socio economic factors associated with visual impairment can assist in the design of intervention programmes. Such information was collected by the Melbourne Visual Impairment Project (Melbourne VIP). <h3>METHODS</h3> The Melbourne VIP was a population based study of non-institutionalised permanent residents in nine suburbs of the Melbourne metropolitan area aged 40 years of age and older. A standardised eye examination was provided to eligible residents which included a structured interview. Variables of interest for this analysis were age, sex, country of birth, language spoken at home, education level, use of private health insurance, employment status, and living arrangements. Visual impairment was defined as a best corrected visual acuity &lt;6/18 and/or visual field constriction to within 20° of fixation <h3>RESULTS</h3> A total of 3271 (83%) residents participated. Participants ranged in age from 40 to 98 years; 54% were female. Forty four (1.34%) were classified as visually impaired due to visual acuity and/or visual field loss. To evaluate the independent association of the significant sociodemographic variables with visual impairment, a regression model was constructed that included age, retirement status, use of private health insurance, and household arrangement. The results showed that age was the significant predictor of visual impairment (OR: 3.19; CI: 2.29–4.43), with the mean age of people with visual impairment significantly older (75.0 years) compared with people without visual impairment (58.2 years) (<i>t</i>test=9.71; p=0.0001). Of the 44 visually impaired people, 39 (87%) were aged 60 years of age and older. <h3>CONCLUSION</h3> The results indicate that age is the most significant factor associated with visual impairment. Of some importance was the finding that people with visual impairment were less likely to have private health insurance. With the aging of the population, the number of people affected by visual impairment will increase significantly. Intervention programmes need to be established before the onset of middle age to offset the escalation of visual impairment in the older population.