Unmet needs and depression among carers of people newly diagnosed with cancer

AIMS

The aims of this analysis were to examine levels of unmet needs and depression among carers of people newly diagnosed with cancer and to identify groups who may be at higher risk, by examining relationships with demographic characteristics.

METHODS

One hundred and fifty dyads of people newly diagnosed with cancer and their carers, aged 18 years and older, were recruited from four Australian hospitals. People with cancer receiving adjuvant cancer treatment with curative intent, were eligible to participate. Carers completed the Supportive Care Needs Survey-Partners & Caregivers (SCNS-P&C45), and both carers and patients completed the Centre of Epidemiologic-Depression Scale (CES-D).

RESULTS

Overall, 57% of carers reported at least one, 37% at least three, 31% at least five, and 15% at least 10 unmet needs; the most commonly endorsed unmet needs were in the domains of information and health care service needs. Thirty percent of carers and 36% of patients were at risk of clinical depression. A weak to moderate positive relationship was observed between unmet needs and carer depression (r=0.30, p<0.001). Carer levels of unmet needs were significantly associated with carer age, hospital type, treatment type, cancer type, living situation, relationship status (in both uni- and multi-factor analysis); person with cancer age and carer level of education (in unifactor analysis only); but not with carer gender or patient gender (in both uni- and multi-factor analyses).

CONCLUSION

Findings highlight the importance of developing tailored programmes to systematically assist carers who are supporting patients through the early stages of cancer treatment.

Development of a conceptual model of cancer caregiver health literacy

Caregivers play a vital role in caring for people diagnosed with cancer. However, little is understood about caregivers' capacity to find, understand, appraise and use information to improve health outcomes. The study aimed to develop a conceptual model that describes the elements of cancer caregiver health literacy. Six concept mapping workshops were conducted with 13 caregivers, 13 people with cancer and 11 healthcare providers/policymakers. An iterative, mixed methods approach was used to analyse and synthesise workshop data and to generate the conceptual model. Six major themes and 17 subthemes were identified from 279 statements generated by participants during concept mapping workshops. Major themes included: access to information, understanding of information, relationship with healthcare providers, relationship with the care recipient, managing challenges of caregiving and support systems. The study extends conceptualisations of health literacy by identifying factors specific to caregiving within the cancer context. The findings demonstrate that caregiver health literacy is multidimensional, includes a broad range of individual and interpersonal elements, and is influenced by broader healthcare system and community factors. These results provide guidance for the development of: caregiver health literacy measurement tools; strategies for improving health service delivery, and; interventions to improve caregiver health literacy.

The effectiveness of callback counselling for smoking cessation: a randomized trial

AIMS

The development of acceptable, widely available and effective smoking cessation methods is central to public health strategy for tobacco control. We examined the effectiveness of a telephone callback counselling intervention, compared to the provision of self-help resources alone.

METHODS

Participants were 998 smokers calling a state-wide "Quitline" service randomly allocated to either callback counselling or ordinary care. The callback condition consisted of a series of brief counselling calls at strategic times in addition to ordinary care. The number of calls varied according to caller needs, and most occurred generally just before the person's quit day and in the week or two after it. The service was delivered by trained telephone counsellors.

RESULTS

At the 3-month follow-up, significantly more participants in the callback group (24%) reported that they were quit, compared to those in the usual care comparison group (13%). The difference in point prevalence of smoking declined to 6% by the 12-month follow-up. Using sustained abstinence there was a significant benefit of callback counselling at 12-month follow-up. Treating dropouts as smokers reduced the overall magnitude of the effects somewhat. The benefit of callbacks was to marginally increase quit attempts and to significantly reduce relapse.

CONCLUSION

Our findings are consistent with those of other studies demonstrating benefits of callback telephone counselling to facilitate cessation. Such counselling provides a flexible, relatively inexpensive and widely available form of cessation service. It appears to encourage a greater proportion of quit attempts and to reduce the rate of relapse among those quitting. Further research is required to determine ways to enhance effectiveness, particularly studies of how to reduce relapse.

Knowledge, attitudes and self-care practices related to sun protection among secondary students in Australia

The aim of this research was to ascertain changes in sun-related knowledge, attitudes and self-care practices among Australian secondary school students between 1993 and 1996. Two cross-sectional surveys of sun-related attitudes, beliefs and behavior of young people aged 12-17 years of age, were conducted in 1993 and 1996. Over 80% of adolescents at both time periods knew about the issues related to skin cancer prevention, frequency of burning and burning on cloudy days. Adolescent attitudes had shifted positively in the areas of staying inside in 1996 [relative risk (RR): 1.13; 95% confidence interval (CI): 1.09-1.17] and staying under shade in 1996 (RR: 1.16; 95% CI: 1.13-1.18). Desire for a moderate or dark tan was lower in 1996 (45%) than in 1993 (50%). Respondents reported that they were less likely to wear brief clothing to get a suntan in 1996 (RR: 0.81; 95% CI: 0.78-0.84) and were significantly more likely to stay in the shade in 1996 (RR: 1.19; 95% CI: 1.16-1.23). We conclude that there has been a shift in attitudes towards use of shade and avoidance of unnecessary exposure, and away from use of sunscreens and sunglasses. The results suggest that adolescents may be more ready to accept structural changes that move desired activities out of the sun.

Recruitment methods for community-based screening for diabetic retinopathy

Regular screening of all people with diabetes is the most efficient and cost-effective way to detect early stages of diabetic retinopathy so that laser treatment can be performed at the optimal time. A major aim of the Program for the Early Detection of Diabetic Retinopathy was to increase compliance with guidelines for screening for diabetic retinopathy. This community-based screening program used non-mydriatic retinal photography and was initiated in four areas of Victoria, Australia from 1996-1998. Recruitment strategies included targeted mail-outs, provision of the program brochure in English and the main languages spoken in the areas and media promotion in ethnic newspapers and on ethnic radio stations. In Victoria, only 55% of the population with diabetes currently access eye care services at the recommended intervals. This program was able to increase compliance with guidelines to 70% among people with diabetes that had not had a recent eye examination. A total of 1,197 people with diabetes were screened for diabetic retinopathy. Of the 1,197 people who were screened, 620 (15% of the estimated number of people with diabetes) had not had their eyes examined in the past two years. This pilot study identified strategies to encourage people with diabetes to have their eyes examined at the recommended intervals.

Examination compliance and screening for diabetic retinopathy: a 2-year follow-up study

Early detection and timely treatment of diabetic retinopathy can preserve vision, yet many people with diabetes do not have their eyes examined regularly. The purpose of this study was to examine eye care practices of people with diabetes who had not previously accessed eye care services on a regular basis. Screening with non-mydriatic retinal photography for diabetic retinopathy was initiated in 1996, and targeted people with diabetes who did not access eye care services on a regular basis. Each test area was revisited 2 years after the initial screening. Patients that did not attend the biennial screening were followed up by mail survey. Although none of the participants in this study had been previously accessing eye care services on a regular basis, 87% did so after attending the screening. These results indicate that mobile screening with non-mydriatic photography, as an adjunct to current eye care services, has the potential to increase examination compliance for diabetic retinopathy and to achieve sustained behaviour change.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Ocular exposure to UV-B in sunlight: the Melbourne visual impairment project model

Quantification of ocular exposure to ultraviolet-B radiation (UV-B) has become an important public health issue, with reports that the ozone layer is being depleted worldwide. Ocular exposure to UV-B is determined by ambient UV-B levels, the duration of outdoor exposure, the proportion of ambient UV-B that reaches the eye, and the use of ocular protection. We have developed a simplified model for quantifying lifetime ocular UV-B exposure that can be used in large epidemiological surveys. Exposure to UV-B is assessed and quantified using a model based on personal exposure over the six summer months. Data available for a population-based sample of 1150 people in the age range 40-98 years revealed a distribution in average annual lifetime ocular UV-B exposure similar to that reported in a previous study on which this model is based, and also demonstrate that people can recall lifetime personal behaviour related to ocular protection. It takes 12 minutes on average to collect these data. This model can be employed by researchers worldwide for uniform assessment of ocular UV-B exposure.

The epidemiology of cataract: a review of the literature

Cataract is a major cause of blindness, accounting for nearly half of all blindness worldwide. Epidemiological research provides the principles and methods to assess the extent of cataract, and supplies the necessary information for policy planning. Obtaining accurate epidemiological data on cataract is essential to ascertain and estimate the cost of primary and secondary eye health care needs. Determining risk factors is also necessary to reduce the economic and social repercussions associated with the disease. The following paper presents a review of the epidemiology of cataract in the middle to elderly age group.

Knowledge of glaucoma, and its relationship to self-care practices, in a population sample

OBJECTIVE

To determine the level of knowledge of glaucoma in a population-based sample, and its relationship to self-care practices.

DESIGN AND SUBJECTS

A cluster random sample of the Melbourne population 40 years of age and older was interviewed. One thousand seven hundred and eleven residents living in five randomly selected Melbourne metropolitan suburbs, each consisting of two adjacent census collector districts.

MEASURES

Questions were asked concerning respondents' awareness, knowledge and description of the disease. Respondents were also asked the year of their last visit to their eye health care provider.

RESULTS

Seventy per cent of the sample had heard of glaucoma. However, only 22% provided a description that demonstrated a reasonable understanding of the disease. A lack of awareness and knowledge of glaucoma appeared to be negatively related to self-care practices.

CONCLUSION

Serious deficiencies in the basic knowledge of glaucoma in the community was demonstrated. This has significant public health implications as only a small percentage of the at-risk population may present themselves for assessment and treatment. Informing the community about glaucoma is an important step in promoting preventative ophthalmic care and reducing visual impairment and blindness.

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.

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.

The importance of epidemiology in understanding eye disease

Most leading causes of visual impairment are age related, so the health care implications of an increasing prevalence of eye disease in the elderly are significant. Epidemiological research provides the foundation to address immediate and long-term needs associated with visual impairment and eye disease. It contributes to a community's knowledge of the presence, diagnosis, characteristics, and distribution of eye conditions affecting the elderly. Obtaining accurate epidemiological information on the extent of visual impairment and eye disease in the community is essential to determine and estimate the cost of primary and secondary eye health care needs.

Mammographic screening: measurement of the cost in a population based programme in Victoria, Australia

STUDY OBJECTIVES

To estimate the cost per woman participating in a mammographic screening programme, and to describe methods for measuring costs.

DESIGN

Expenditure, resource usage, and throughput were monitored over a 12 month period. Unit costs for each phase of the screening process were estimated and linked with the probabilities of each screening outcome to obtain the cost per woman screened and the cost per breast cancer detected.

SETTING

A pilot, population based Australian programme offering free two-view mammographic screening.

PARTICIPANTS

A total of 5986 women aged 50-69 years who lived in the target area, were listed on the electoral roll, had no previous breast cancer, and attended the programme.

RESULTS

Unit costs for recruitment, screening, and recall mammography were $17.54, $60.04, and $175.54, respectively. The costs of clinical assessment for women with subsequent clear, benign, malignant (palpable), and malignant (impalpable) diagnoses were $173.71, $527.29, $436.62, and $567.22, respectively. The cost per woman screened was $117.70, and the cost per breast cancer detected was $11,550.

CONCLUSIONS

The cost per woman screened is a key variable in assessment of the cost effectiveness of mammographic screening, and is likely to vary between health care settings. Its measurement is justified if decisions about health care services are to be based on cost effectiveness criteria.

Effectiveness, costs, and cost-effectiveness of recruitment strategies for a mammographic screening program to detect breast cancer

BACKGROUND AND PURPOSE

Since effective and affordable recruitment methods are essential for the widespread implementation of mammographic screening for detection of breast cancer, we studied the effectiveness, the costs, and the cost-effectiveness of various recruitment strategies in the population targeted by a pilot Australian program that offered free mammography screening between 1988 and 1990.

METHODS

We evaluated three public recruitment strategies--local newspaper articles, community promotion, and promotion to physicians--and five personal strategies--invitation letters with or without specified appointment times, either alone or with a follow-up letter, or telephone call to nonattenders. The effectiveness of public recruitment strategies was estimated from monthly attendance rates by Poisson regression analysis, while the probability of attendance in response to personal strategies was calculated using logistic regression analysis. Costs were determined by resource usage studies. The cost-effectiveness ratios for personal strategies were determined using decision analysis.

RESULTS

The costs in 1988-1989 Australian dollars per woman recruited were $22 for local newspaper articles and $106 for community promotion. No detectable increase in attendance resulted from promotion to physicians. When the cost of reserving an appointment was considered, the most cost-effective personal recruitment strategy was an invitation letter without a specified appointment time, followed by a second letter to nonattenders. This strategy recruited 35.6% of women in the sample targeted and cost $10.52 per attendee. In comparison, the most effective personal recruitment strategy was a letter with a specified appointment time followed by a second letter to nonattenders, which recruited 44.1% of women at an average cost of $19.99 and a marginal cost of $59.71 per additional attendee.

CONCLUSIONS

Personal recruitment strategies were more cost-effective than public strategies. The most cost-effective personal strategy was an invitation letter without a specified appointment time, followed by a second letter to nonattenders.

Personal costs incurred by women attending a mammographic screening programme

A survey of the personal costs (travel and time) incurred by 150 randomly selected women attending a mammographic screening programme indicated that 74% travelled by car and 78 (52%) were accompanied by another person. Of the 78 accompanying persons 16 also had a breast x-ray. Fifteen women in the survey and 10 of the unscreened accompanying persons had taken leave from work to attend the programme, and this leave was unpaid for five women and two unscreened accompanying persons. The mean travel costs, out-of-pocket expenses, and opportunity costs per attendance were $6.45, $8.14, and $13.75, respectively. The personal costs involved in attending a screening programme appear to be substantial and may deter women from attending.

Patterns of surgical treatment of breast cancer in Victoria

We analysed data on admissions to Victorian public hospitals for surgical treatment of breast cancer over the period July 1985 to December 1988. Of the 2993 women admitted, 28.7% received breast-preserving surgery. The probability of a woman being treated conservatively was dependent on age, with women aged less than 50 or more than 70 years more likely to receive breast-preserving surgery than women aged 50-69. There was an age-specific change, of marginal statistical significance, in the proportion of women receiving breast-preserving surgery over the period. The public hospitals admissions database is a potentially useful means of monitoring patterns of surgical treatment.

Line-shape flattening resulting from hypersonic nozzle wedge flow in low-pressure chemical lasers

The new hypersonic wedge nozzle (HYWN) supersonic wedge nozzle design produces a significant component of directed gas flow along the optical axis of a laser cavity comparable to thermal speeds. The gain-line-shape function is broadened and the refractive-index line shape is also spread as a function of wedge-flow half-angle. An analytical treatment as well as a numerical study is presented that evaluates the Doppler-directed-flow impact on the number of longitudinal modes and their frequencies as well as on gain and refractive-index saturation of those that lase in a Fabry-Perot cavity.

Comparison of measured 3.8-microm scattering from naturally occurring aerosols with that predicted by measured particle size statistics

Recent field measurements of scattered 3.8-microm laser radiation from naturally occurring aerosols were made during a 4-week period in coastal Southern California. Simultaneously, aerosol distribution measurements were made, which, in conjunction with Mie scattering theory, gave estimates of the volume scattering coefficient at the various angles. A comparison shows that (a) calculated volume scattering coefficients generally decrease more rapidly in angle than measurements indicate; (b) on the average, the calculation gives volume backscattering coefficients that are a factor of 2 larger than measured but underpredicts forward scattering by 33%. A second unrelated observation of interest is that volume scattering coefficients in the visible showed 65% correlation with 3.8-microm backscatter (177 degrees ) coefficients.

Study of Target Edge Response Viewed Through Atmospheric Turbulence over Water

Photographed edge response of a quadrant target made through atmospheric turbulence at a range of 1.6 km 10.7 m above water was found to fit an error function form quite accurately. A theoretical estimate of the intensity point spread function based upon a parabolic approximation to the wave structure function for a point source is consistent with the data. Assuming the validity of the approximation, thermal values of C(n) give turbulence inner scales in the millimeter range.

Thermally Induced Modifications of a High Power cw Laser Beam

The problem of beam-induced thermal modifications of a high powered cw laser beam is considered. The extent and type of modification depend principally upon the nature of the medium (liquid or air) and whether an external flow field is present. These conditions determine the dominant heat loss mechanism operating the fluid: forced convection, free convection, and diffusion and, thus, the beam distortions. All three cases are analyzed and figures presented, showing the type of distortion expected as determined within the framework of geometric optics.