Compliance with recommendations from a screening programme for diabetic retinopathy

METHODS: General practitioner compliance with recommendations for patient follow-up after participation in a screening programme for diabetic retinopathy was assessed. Six months after screening with non-mydriatic retinal photography in four areas of Victoria, the genera practitioner of each participant was surveyed if the participant reported no examination for diabetic retinopathy in the past 2 years and if the results of the screening indicated the need for further assessment. RESULTS: Overall, 208 of 253 (82%) completed questionnaires were analysed. A total of 123 (59%) patients were referred by their doctors for further assessment and 97 (79%) of those referred were reported to have complied with the referral. Of the 85 (41%) patients who were not referred for further assessment, 31 (36%) were reported by their doctors to be already under regular review by an ophthalmologist. CONCLUSIONS: Compliance with genera practitioner referrals suggests that this screening programme was effective and a useful means by which to remind general practitioners of the importance of regular eye examinations for people with diabetes.

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.

Use of focus groups to identify health promotion strategies for the early detection of diabetic retinopathy

BACKGROUND: People with diabetes do not regularly utilise eye services for the early prevention of vision loss due to diabetic eye disease. A community-based screening program has been initiated in Victoria to address this issue. To encourage people to take preventive eye health care measures, the most effective health promotion strategies were identified. METHODS: Thirty-three health professionals were invited to attend focus groups. A sample of 35 people with diabetes was approached by their GPs or diabetes educators because of their motivation to participate in diabetes activities. Each group consisted of 10 members. Discussion points included the type of education messages available to people with diabetes; use of eye services among the participants with diabetes; and strategies required promoting the screening service. RESULTS: Five focus groups were conducted. The discussions highlighted that a great deal could be achieved by using local community networks to promote the benefits of early detection of diabetic retinopathy and local screening program. The group members recommended that particular attention be directed to general practitioners and their distribution of materials to patients. Key issues for planning and implementing the program were highlighted. The groups urged development of strategies to encourage people with diabetes in rural Victoria to participate in a program for the early detection of diabetic retinopathy.

Knowledge, attitudes, and self care practices associated with age related eye disease in Australia

AIM: To determine the level of correct knowledge about common eye disease and attitudes towards blindness prevention and treatment, and how these factors influence self care practices in a population based sample. METHODS: A cluster random sample of the Victorian population was interviewed. The study population comprised residents aged 40 years of age or older living in five randomly selected Melbourne metropolitan suburbs and four randomly selected rural areas of Victoria. Questions were asked to ascertain each person's knowledge of common age related eye disease--that is, cataract, age related macular degeneration (AMD), and glaucoma. A subsample of the population was also asked questions to determine their attitudes to blindness prevention and treatment. All respondents were asked the year of their last visit to an eye practitioner. RESULTS: A total of 3184 (89%) eligible residents were assessed. Sex (females), age (younger people), higher levels of education (secondary, trade, or tertiary education), recent visit to an eye practitioner (within the past 2 years) and English spoken at home appeared to be significant predictors of knowledge of common age related eye conditions. Younger people believed blindness prevention and blindness treatment were the highest priorities compared with other diseases; people who spoke English at home and people with knowledge of common age related eye disease also considered blindness treatment to be the highest priority compared with other diseases. People with a previous diagnosis of age related eye disease, older people, females, people with correct knowledge of common eye diseases, and those who spoke English at home were significantly more likely to be under eye care. No interaction was found between knowledge and positive attitudes to self care practices. CONCLUSION: These data show that there is a large gap in the public's knowledge and understanding of eye disease that will need to be understood for eye health promotion activities.

Screening for diabetic retinopathy using a non-mydriatic retinal camera in rural Victoria

PURPOSE: To develop a screening programme for the early detection of diabetic retinopathy using non-mydriatic retinal photography. METHODS: A community based screening service was offered to all people with known diabetes mellitus in selected townships in the LaTrobe and Goulburn Valleys in Victoria. At the local examination centre, basic sociodemographic information was collected as well as details of previous use of eye care services for the early detection of diabetic retinopathy. The examination included visual acuity (VA), glycosylated haemoglobin level and Polaroid photographs of each fundus using a Canon CR5-45NM non-mydriatic retinal camera (Canon, Tochigiken, Japan). Dilating drops were not used. Photographs were subsequently reviewed and letters were sent to all participants (with copies to their general practitioners) with recommendations for appropriate follow up. RESULTS: A total of 1177 people with diabetes attended the screening service, which is estimated to be 40% of the total population with known diabetes in the study area. The mean age was 65 years (range 20-94 years); 559 (48%) people reported not having a dilated fundus examination within the past 2 years; 345 (29%) people had never had a dilated fundus examination. Of the 2354 eyes, 2126 (90%) of the photographs were gradable. A total of 704 people (60%) had normal VA and no evidence of diabetic retinopathy, 209 people (18%) had diabetic retinopathy, 101 people (9%) had evidence of other fundus pathology, 42 people (3%) had reduced acuity (< 6/18) in one or both eyes (with no fundus pathology evident) and 121 people (10%) had ungradable photographs in one or both eyes. CONCLUSIONS: The present study demonstrates the usefulness of a screening programme with non-mydriatic retinal photography as an adjunct to current eye care services for the early detection of diabetic retinopathy.

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.

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

AIM: The 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 representative sample of Melbourne residents 40 years of age and older. METHODS: A comprehensive interview was employed to elicit information on history of diabetes, medication use, most recent visit to an ophthalmologist and optometrist, and basic demographic details. Presence and extent of diabetic retinopathy was determined by dilated fundus examination. RESULTS: The Melbourne VIP comprised 3271 people who ranged in age from 40 to 98 years; 46.2% of them were male. Of 3189 people who had the fundus examination and knew their diabetes status, 162 (5.1%) reported having been previously diagnosed with diabetes and, of these, 37 (22.2%) were found to have diabetic retinopathy. Seven people (4.3%) had developed diabetes before age 30. The mean duration of diabetes was 9.2 years. People with diabetes were significantly more likely to have visited an ophthalmologist ever or in the past 2 years than people without diabetes. However, 31.8% of people with diabetes had never visited an ophthalmologist. The proportion of people who had never seen an ophthalmologist was 47.1% for people without diabetes, 34.2% for people with diabetes but without diabetic retinopathy, and 25% for people with diabetic retinopathy. Sixty one per cent of people with diabetic retinopathy had seen an ophthalmologist in the past year and a further 3% within the past 2 years. People with diabetes were not significantly more likely to have visited an optometrist than people without diabetes (p = 0.51). Overall, 37.7% of people with diabetes and 32.9% of people without diabetes had visited an optometrist within the past year (chi 2 = 2.25, 1 df, p = 0.13). Information concerning retinal examinations was available for 135 individuals (83.3% of people with diabetes). Only 74 (54.8%) could recall ever having a dilated fundus examination; 10 (14%) by an optometrist, 62 (86%) by an ophthalmologist, and five (7%) by a general practitioner. Of those 68 people who had seen an ophthalmologist in the past 2 years, 48 (71%) reported a dilated fundus examination during that time. This compares with 28 (43%) reported dilated fundus examinations in the 65 people who had seen an optometrist in the past 2 years. This finding is statistically significant (chi 2 = 10.2, 1 df, p < 0.005). CONCLUSION: These results indicate that nearly half of people with diabetes in Melbourne are not receiving adequate screening or follow up for diabetic retinopathy, despite universal health care.

Visual impairment and socioeconomic factors

BACKGROUND: Information about socioeconomic 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). METHODS: 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 < 6/18 and/or visual field constriction to within 20 degrees of fixation. RESULTS: 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) (t test = 9.71; p = 0.0001). Of the 44 visually impaired people, 39 (87%) were aged 60 years of age and older. CONCLUSION: 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.

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 in 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.

Visual impairment in Australia: distance visual acuity, near vision, and visual field findings of the Melbourne Visual Impairment Project

PURPOSE: To describe the age-specific and gender-specific rates of blindness and visual impairment in urban adults aged 40 years and older. METHODS: 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. RESULTS: 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%). CONCLUSIONS: 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.

Prevalence of Myopia in adults: implications for refractive surgeons

BACKGROUND: We reviewed the research on the prevalence of myopia in the adult population to compare the refractive distribution of patients being treated with excimer laser photorefractive keratectomy to correct myopia, and assess the potential market for excimer laser surgery. METHODS: All published reports of myopia prevalence in adults were reviewed, as well as the prevalence in the Melbourne Visual Impairment Project and the distribution of refractive errors treated by the Melbourne Excimer Laser Group in 1994. RESULTS: A large population-based study of people aged 4 to 74 years in the U.S. showed that 43% had low myopia (less than -5.00 diopters (D)), 3.2% had high myopia (-5.01 to -10.00 D), and 0.2% had extreme myopia (more than -10.00 D). In Asian populations these proportions may be much higher and in African and Pacific island groups, much lower. In the Melbourne Visual Impairment Project, we found the prevalence of low myopia was 21%, high myopia 2%, and extreme myopia 0.3%. A single excimer laser has operated for 3 years in Melbourne. Of those treated, 45% had low myopia, 42% high myopia, and 13% extreme myopia. Compared to low myopes, high myopes were ten times (OR: 9.8; Confidence interval: 6.69 to 12.91) more likely to have excimer laser treatment and extreme myopes were 16 times (OR: 16.40; Confidence interval: 12.53 to 20.27) more likely. CONCLUSIONS: Although there are many more people with lower amounts of myopia in the population and the clinical results have been more predictable after one procedure in this group, the perceived benefits of excimer laser treatment may be greater for those with higher amounts of myopia, thus influencing their decision to undergo excimer laser surgery to correct their myopia. There is clearly a large market potential for excimer laser surgery in people with low myopia.

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.