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The Lancet 12/2012; · 38.28 Impact Factor
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ABSTRACT: Two-thirds of the world's population with low vision resides in the Asia-Pacific region. Provision of comprehensive low vision services is important to improve vision-related quality of life (QoL) for people with this condition. This review outlines the critical issues and challenges facing the provision of low vision services in the Asia-Pacific region. The review offers possible strategies to tackle these issues and challenges facing service providers and policy makers in lieu of Vision 2020 strategies in this area. Pertinent findings from the global survey of low vision services and extensive ground work conducted in the region are used; in addition, a discussion on the availability of services, human resources and training, and funding and the future sustainability of low vision care will be covered. In summary, current issues and challenges facing the region are the lack of specific evidence-based data, access, appropriate equipment and facilities, human resources, funding, and sustainability. These issues are inextricably interlinked and thus cannot be addressed in isolation. The solutions proposed cover all areas of the VISION 2020 strategy that include service delivery, human resources, infrastructure and equipment, advocacy and partnership; and include provision of comprehensive care via vertical and horizontal integration; strengthening primary level care in the community; providing formal and informal training to enable task shifting and capacity building; and promoting strong government and private sector partnership to achieve long-term service financial sustainability.
Indian Journal of Ophthalmology 09/2012; 60(5):456-9. · 1.02 Impact Factor
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ABSTRACT: To obtain utility weights consistent with the needs of economic evaluation for the Assessment of Quality of Life (AQoL)-7D, a generic instrument created to increase the sensitivity of the measurement of quality of life amongst people with impaired vision.
Two extant instruments were combined, the Vision-related Quality of Life Index (VisQoL) and the AQoL-6D. Utilities were obtained from patients with visual impairment and from the general population using time trade-off (TTO) methodology. Dimensions were combined and an econometric adjustment used to eliminate the effects of instrument redundancy. Bias was tested by comparison of holistic TTO values with utility scores predicted from the AQoL-7D scoring formula.
The AQoL-7D instrument consists of 26 items and 7 dimensions each with good psychometric properties. Their combination into a single instrument resulted in significant redundancy which was successfully eliminated. Utility formulae for both the public and patients produced bias-free estimates of the utility of holistic health states describing visual impairment. Results imply differing valuations of health states by the public and by people with impaired vision.
The AQoL-7D can detect changes in health states affecting people with impaired vision which are likely to be overlooked by other generic instruments due to content insensitivity. The utilities it produces are generated using a "mainstream" methodology, the TTO. Quality-adjusted life year values based on the AQoL-7D may therefore be used for economic evaluation of programs.
Ophthalmic epidemiology 06/2012; 19(3):172-82. · 1.93 Impact Factor
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ABSTRACT: To assess the prevalence of diabetes and diabetic retinopathy in indigenous Australians aged ≥40 years.
The National Indigenous Eye Health Survey used a stratified, multistage cluster probability sampling frame to provide a representative sample of the indigenous Australian population.
One thousand one hundred and eighty-nine eligible indigenous adults were examined using standardized procedures.
Each participant underwent a comprehensive eye examination included presenting and best corrected visual acuity, visual field, fundus and lens photography.
Diabetic retinopathy.
The prevalence of diabetes in the 1189 eligible indigenous adults was 37.3% (95% confidence interval: 34.6-40.2%). The prevalence of diabetic retinopathy among 394 people with diabetes was 29.7% (95% confidence interval: 25.2-34.2%), and 17.8% (95% confidence interval: 14.0-21.6%), 8.9% (95% confidence interval: 6.1-11.7%) and 3.1% (95% confidence interval: 1.3-4.7%) for mild or moderate diabetic retinopathy, clinically significant macular oedema and severe or proliferative diabetic retinopathy, respectively. Diabetic retinopathy was presented in 6.3% in those who did not report diabetes. The risk of diabetic retinopathy increased with duration of diabetes (the adjusted odds ratios were 3.4 for 10-19 years, 6.1 for 20-29 years and 25.8 for ≥30 years).
The prevalence of self-reported diabetes in indigenous Australians is more than eight times higher than that in non-indigenous Australians. The prevalence of diabetic retinopathy in people with diabetes is similar to that of non-indigenous Australians.
Clinical and Experimental Ophthalmology 08/2011; 39(6):487-93. · 1.98 Impact Factor
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ABSTRACT: A survey to determine the prevalence of trachomatous trichiasis (TT) requires a large sample size and the recommended participant age is ≥15 years. This study sought to establish the appropriate age range of individuals to be included in TT surveys.
Data from six previous surveys of adults ≥15 years old were reanalysed.
Reanalysis indicated that 69.6-93.3% (average 87.0%) of untreated TT occurred in those aged 40+ years and 52.2-86.7% (average 73.1%) in those aged 50+ years (age ≥50 years is used in rapid assessment of avoidable blindness). Age ≥40 years was adopted in a TT survey conducted in Turkana district because it allowed a smaller sample size than age ≥15 years.
The estimated backlog of untreated TT in people aged ≥40 years old in Turkana was 5932 and the overall TT backlog was likely to be 6358-8523. These findings cannot be generalised because all surveys were carried out in the same country.
The British journal of ophthalmology 04/2011; 95(8):1058-60. · 2.92 Impact Factor
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ABSTRACT: To review the process of sample selection and highlight the methodological difficulties encountered during a nationwide survey of Indigenous Australians, to determine the prevalence and causes of vision impairment and evaluate access to and utilisation of eye care services.
Using a multi-stage, random cluster sampling methodology, 30 geographic areas stratified by remoteness, were selected to provide a representative population of approximately 3,000 Indigenous Australians aged 5-15 and 40 years and older, and a small non-Indigenous sample in selected remote areas. Recruitment was adapted to local conditions. The rapid assessment methodology included a questionnaire, tests of visual acuity, trachoma grading, frequency doubling perimetry and non-mydriatic fundus photography.
The number of people examined was 2883/3662 (78.7%) Indigenous and 136 (83.4%) non-Indigenous. The percentage of the expected population who were enumerated during the survey varied; discrepancies were largest in urban areas (34.5%) compared to very remote areas (97.1%).
The unexpected variation in predicted population numbers and participation rates could be explained in part by local circumstances, degree of urbanisation, interpretation of the definition of 'Indigenous' and time constraints.
For successful recruitment, a community-specific approach is essential, including collaboration with local organisations and liaison with health workers of each gender.
Australian and New Zealand Journal of Public Health 12/2010; 34(6):554-62. · 1.20 Impact Factor
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ABSTRACT: To identify the critical success factors (CSF) associated with coverage of low vision services.
Data were collected from a survey distributed to Vision 2020 contacts, government, and non-government organizations (NGOs) in 195 countries. The Classification and Regression Tree Analysis (CART) was used to identify the critical success factors of low vision service coverage. Independent variables were sourced from the survey: policies, epidemiology, provision of services, equipment and infrastructure, barriers to services, human resources, and monitoring and evaluation. Socioeconomic and demographic independent variables: health expenditure, population statistics, development status, and human resources in general, were sourced from the World Health Organization (WHO), World Bank, and the United Nations (UN).
The findings identified that having >50% of children obtaining devices when prescribed (χ(2) = 44; P < 0.000), multidisciplinary care (χ(2) = 14.54; P = 0.002), >3 rehabilitation workers per 10 million of population (χ(2) = 4.50; P = 0.034), higher percentage of population urbanized (χ(2) = 14.54; P = 0.002), a level of private investment (χ(2) = 14.55; P = 0.015), and being fully funded by government (χ(2) = 6.02; P = 0.014), are critical success factors associated with coverage of low vision services.
This study identified the most important predictors for countries with better low vision coverage. The CART is a useful and suitable methodology in survey research and is a novel way to simplify a complex global public health issue in eye care.
Investigative ophthalmology & visual science 10/2010; 52(5):2790-5. · 3.43 Impact Factor
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ABSTRACT: To survey the current diabetic retinopathy screening and management practices of Australian optometrists following the release of the 1997 National Health Medical Research Council Diabetic Retinopathy Management Guidelines.
Cross-sectional national survey, primary care setting.
1000 Australian optometrists across different states.
A self-administered questionnaire was sent to 1000 optometrists across all states during 2007/2008.
Use of retinal camera, screening practices/attitudes and behaviour in diabetic retinopathy management.
568 optometrists (57%) responded to the survey. Patients' unpreparedness to drive post dilation (51%) and the fear of angle closure glaucoma (13%) were the two main barriers to optometrists not performing dilated ophthalmoscopy. Those who had strong desire to screen for diabetic retinopathy were more likely to use a retinal camera (p<0.005). Use of a retinal camera was significantly associated with an increased confidence in detecting clinical signs of diabetic retinopathy including macular oedema (P<0.001). Optometrists who read the guidelines at least once were 2.5-times (P<0.001) more likely to have confidence in detecting macular oedema than those who had never read the guidelines. Although they may be confident in diagnosis, and may use retinal cameras for screening, nearly 60% of optometrists would not refer patients with macular oedema to an ophthalmologist.
Despite their self-reported desire for involvement in diabetic retinopathy, the management of macular oedema by Australian optometrists needs improvement. The use of retinal cameras and promotion of the 2008 NHMRC guidelines should be encouraged to improve overall optometric diabetic retinopathy management, particularly with macular oedema.
Clinical and Experimental Ophthalmology 10/2010; 39(3):230-5. · 1.98 Impact Factor
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ABSTRACT: To compare the self-reported management of diabetic retinopathy by Australian ophthalmologists with the 1997 National Health and Medical Research Council (NHMRC) guidelines.
Self-reported cross-sectional survey of patterns of practice. Questionnaires were sent to all Australian ophthalmologists, comprising questions regarding professional details, diabetic retinopathy screening attitudes/practices and specific hypothetical management scenarios. Data were analysed using Chi-squared and adjusted logistic regression.
480 of the 751 (64%) eligible Australian ophthalmologists participated. The majority (80%, n = 376) reported they consistently reviewed patient's glycaemic control, but only 55% and 41% regularly reviewed blood pressure and serum cholesterol control, respectively. Ophthalmologists generally adhered to NHMRC-recommended screening intervals, although only 38% agreed with the guidelines relating to screening of pre-pubertal diabetic patients. Fluorescein angiogram was used more than recommended, especially for mild non-proliferative diabetic retinopathy where 45% of respondents used this investigation. Practice duration >15 years was associated with more regular fluorescein angiogram use (OR = 3.74; 95% CI: 2.53-5.53, P < 0.001). In the clinical scenarios where clinically significant macular oedema was concurrently present with cataract or proliferative diabetic retinopathy, >26% referred to retinal subspecialists for management; 85% of the remaining ophthalmologists performed macular laser first. Respondents with practice duration >15 years were 7.8 times (P = 0.001) more likely to perform cataract surgery first.
Diabetic retinopathy management guidelines were generally well followed by Australian ophthalmologists. However, areas of practice variation existed including frequent use of fluorescein angiogram. Significant proportion of practitioners referred diabetic patients to retinal subspecialists, who were more likely to adhere to guideline recommendations. Ophthalmologists with greater experience (>15 years) were more likely to employ practices differing from NHMRC recommendations.
Clinical and Experimental Ophthalmology 08/2010; 38(6):613-9. · 1.98 Impact Factor
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ABSTRACT: To determine the prevalence of vision loss due to cataract in indigenous Australians.
A national, stratified, random cluster sample was selected in 30 communities across Australia. Data collection was undertaken in 2008. Adults 40 years and older were examined using a standardized protocol that included a questionnaire. The presence of visually significant cataract was assessed.
Response rates were good and 1189 indigenous adults were examined and overall recruitment was 72%. Low vision (<6/12-6/60) due to cataract occurred in 2.52% (1.63-3.41%) and blindness (<6/60) in 0.59% (95% CI: 0.24-1.21%). The cataract coverage rate (proportion of those with visually significant cataract who had been operated on) was 65.3% (95% CI: 55.0-74.6%). Projections suggest that there are 3234 indigenous adults with vision loss from cataract.
Cataract remains a major cause of vision loss in Aboriginal and Torres Strait Islander peoples. There were no significant regional or state differences in the prevalence of cataract or of cataract surgical coverage, which suggests that increased cataract surgery services are required across the country to address cataract in indigenous Australians.
Clinical and Experimental Ophthalmology 05/2010; 38(8):790-5. · 1.98 Impact Factor
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ABSTRACT: Falls are an alarming health problem and a major cause of injury among the elderly. The healthcare cost associated with falls is considerable. Visual acuity has been found to be an independent risk factor for falls; however, the results are not unanimous. Moreover, other aspects of visual function such as visual field, contrast sensitivity and depth perception have not been adequately investigated in relation to falls. The aim of this study, therefore, was to determine the relationship between visual function, duration, and main causes of visual impairment, and falls in individuals with low vision.
This was a cross-sectional study involving participants attending a public tertiary eye care hospital. Participants were mobile, aged 60 years or above, and had low vision (visual acuity >0.3 LogMAR in the better eye). Details about falls in the previous 12 months and other information were collected, and patients completed a questionnaire about activities of daily living. The duration and main causes of visual impairment, visual acuity, contrast sensitivity, depth perception, and visual field were assessed. Descriptive statistical analyses were performed to characterize the participants' sociodemographic and clinical data.
One hundred and twenty seven patients (53%; 67 males) with a mean age of 76.3+/-8.3 years were recruited. Thirty seven percent of the participants (n=47) had mild, 50% (n=64) moderate and 13% (n=16) severe visual impairment (>0.3-0.5; >0.5-1.0; and >1.0 LogMAR respectively). The frequencies of single and multiple falls were 42.5% and 12.6% respectively. Visual acuity, contrast sensitivity, depth perception, visual field, main cause, and duration of visual impairment were not significantly associated with falls (p>0.05). In multiple regression analyses, physical inactivity remained the only variable independently associated with falls in all models except for visual field. Overall, visually impaired people were three times more likely to fall if they were physically inactive.
Visual function, duration and main causes of visual impairment are not independently associated with falls in people with low vision. However, a significant relationship between non-participation in physical activity and falls was found. Further work is required to investigate the association between vision-related factors and falls in older people with visual impairment.
Albrecht von Graæes Archiv für Ophthalmologie 04/2010; 248(4):527-33. · 2.17 Impact Factor
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ABSTRACT: Depression is common in people with vision impairment and further reduces levels of functioning independent of vision loss. However, depression most often remains undetected and untreated this group. Eye health professionals (EHPs) (ophthalmic nurses, ophthalmologists, optometrists, and orthoptists) and rehabilitation workers (RWs) may be able to play a role in detecting depression. This study aimed to identify current practice and investigate factors associated with depression management strategies.
A self-administered cross-sectional survey of EHPs and RWs assessed current practice including confidence in working with depressed people with vision impairment; barriers to recognition, assessment, and management of depression; beliefs about the consequences, duration, and efficacy of treatment for depression in individuals with vision impairment.
Ninety-four participants aged 23 to 69 years took part. Thirty-seven participants (39.8%) stated that they attempted to identify depression as part of patient management, with RWs significantly more likely to do so (n = 17, 60.7%) than EHPs (n = 20, 30.8%; p = 0.007). Intention to identify depression was not associated with sociodemographic factors, professional experience in eye care services, or the length and number of patient consultations, but a significant relationship was found for confidence, barriers, and beliefs about depression (p < 0.05). No consistent depression management strategy emerged and a range of barriers were highlighted.
Training programs are needed to provide EHPs and RWs with the skills and resources to address depression in people with vision loss under their care and to support the development of procedures by which concerns about depression can be identified objectively, documented, and included as part of a referral to appropriate services.
Optometry and vision science: official publication of the American Academy of Optometry 10/2009; 86(12):1328-36. · 1.53 Impact Factor
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ABSTRACT: To investigate whether the Patient Health Questionnaire-9 (PHQ-9) possesses the essential psychometric characteristics to measure depressive symptoms in people with visual impairment.
The PHQ-9 scale was completed by 103 participants with low vision. These data were then assessed for fit to the Rasch model.
The participants' mean +/- standard deviation (SD) age was 74.7 +/- 12.2 years. Almost one half of them (n = 46; 44.7%) were considered to have severe vision impairment (presenting visual acuity <6/60 in the better eye). Disordered thresholds were evident initially. Collapsing the two middle categories produced ordered thresholds and fit to the Rasch model (chi = 10.1; degrees of freedom = 9; p = 0.34). The mean (SD) items and persons Fit Residual values were -0.31 (1.12) and -0.25 (0.78), respectively, where optimal fit of data to the Rasch model would have a mean = 0 and SD = 1. Unidimensionality was demonstrated confirming the construct validity of the PHQ-9 and there was no evidence of differential item functioning on a number of factors including visual disability. The person separation reliability value was 0.80 indicating that the PHQ-9 has satisfactory precision. There was a degree of mistargeting as expected in this largely non-clinically depressed sample.
Our findings demonstrate that the PHQ-9, when scaled with Rasch analysis, forms a linear interval measurement of depressive symptoms suitable for use in a vision impaired population.
Optometry and vision science: official publication of the American Academy of Optometry 02/2009; 86(2):139-45. · 1.53 Impact Factor
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ABSTRACT: A range of medical conditions can lead to visual impairments either through effects on the eye or the visual pathways and brain. The prevalence of visual impairment increases with age. Furthermore, research evidence has shown that aging is related to a number of other processes that can lead to changes in cognitive functioning and sensory perception that may adversely affect driving (Marottoli and Drickamer, 1993; Stelmach and Nahom, 1992). This combination of factors is thought to contribute to older driver crash risk (Hakamies-Blomqvist, 1993; Stutts et al., 1998). Licensing authorities are the primary entity responsible for monitoring the medical fitness of their license holders. While it is important for licensing bodies to identify drivers who have conditions that place them at a heightened risk for crashes, at the same time, they should not unfairly restrict the mobility of disabled or aging drivers. Therefore, it is important that the licensing criteria for visual fitness to drive are based on scientific evidence establishing their effectiveness and predictive value for poor driving performance and unacceptable crash risk. The aim of this paper is to assess whether current licensing guidelines are consistent with the available scientific evidence on the effect of visual impairment on driving with a specific focus on older drivers.
This article describes current licensing guidelines for vision from selected Western jurisdictions and reviews the available scientific evidence on visual impairment and driving performance on which such licensing decisions are based.
The findings of the review indicate that the predictive values of the vision tests commonly used for licensing decisions by the selected authorities are inconclusive.
The functional attributes of vision currently assessed for licensing do not adequately explain unsafe driving performance. Differences were observed across vision requirements for the selected jurisdictions, possibly reflecting the equivocal and inconclusive findings linking specific visual functions and impairment with crash risk. Setting benchmarks or performance thresholds on selected visual tests may be problematic for older drivers in particular, who are most vulnerable to underperforming. Driving involves a complex set of skills, and it is proposed that decisions about vision for safe driving need to be considered in the context of the driver's overall health and other functional abilities.
Traffic injury prevention 09/2008; 9(4):304-13.
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ABSTRACT: To describe and evaluate the procedures used to collect personal costs associated with vision impairment using diaries.
Participants with impaired vision (VA < 6/12 or > or = 6/12 with restricted visual fields) were recruited. Twelve-monthly diaries, provided in large print and electronic format (with audio and Braille instruction manuals and personal assistance), were used to record vision-related expenditures grouped under four categories. Two questionnaires were used to collect additional information and to test the validity of the self-reported costs.
Of 227 people who consented to participate, 66% (n = 150; 91 females; mean age = 64.8 years) completed > or = 3 monthly diaries. Of the 150 eligible participants, 68% completed the diaries over 12 months, indicating a relatively high completion rate. The median total cost was AUD 2,417 dollars per annum and median values for the four expenditure categories ranged between AUD 206 dollars and AUD 872 dollars per annum. The data were consistent across different months with no significant difference found between any monthly comparison (t-test; p > Bonferroni-adjusted value). Data at 1, 3, and 6 months, extrapolated to annual figures, showed no significant difference from annual total costs, indicating consistency in the data collection periods. A significant association was found between diary data and similar entries in the follow-up questionnaire, confirming the validity of the recorded expenditures (Spearman; p < 0.01). Participants commented that the diary method was useful to obtain personal costs.
A high response rate was achieved by using diaries and additional assistance methods. The diary provided an accurate and reliable strategy to determine the major personal costs associated with vision impairment.
Ophthalmic Epidemiology 01/2007; 13(6):355-63. · 1.45 Impact Factor
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ABSTRACT: To identify the content for a vision and quality of life-related utility measure (Vision Quality of Life Index [VisQoL]) for the economic evaluation of eye care and rehabilitation programs.
Focus groups of the visually impaired elicited key concepts. Based on these and previous research, 33 items were generated. These were administered to visually impaired adults (n = 70) and a representative sample of unimpaired adults (n = 86). The item bank was reduced through examination of item properties, exploratory factor (EFA), item response theory (IRT), and structural equation modeling (SEM) analyses. The resultant model was confirmed through administration to a second sample of participants.
Focus group themes included physical well-being, social well-being, independence, self-actualization, emotional well-being, and planning and organization. Poorly performing items were eliminated on basic psychometric properties, including failure to discriminate. Next, EFA loadings were used to select items. Twelve items survived. To minimize redundancy, IRT analysis and SEM reduced the VisQoL item pool to six items (Cronbach alpha = 0.88). To confirm this model, these items were then administered to an additional 218 participants; 35% with a vision impairment. A pooled SEM analysis showed the model to have very good fit properties (root mean square error of approximation [RMSEA] = 0.000). A preliminary test of the model against visual acuity showed a significant monotonic relationship.
The short 6-item VisQoL has excellent psychometric properties as a simple summative instrument. It can be used in its present state as a condition-specific outcome measure for the evaluation of healthcare interventions for the visually impaired. The descriptive model is also suitable for generating utility values for the economic evaluation of vision-related programs and services.
Investigative Ophthalmology & Visual Science 12/2005; 46(11):4007-15. · 3.60 Impact Factor
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Jill Keeffe
Community eye health / International Centre for Eye Health 02/2004; 17(49):3-4.
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ABSTRACT: To describe the psychometric characteristics of the Impact of Vision Impairment (IVI) Profile and evaluate its validity and reliability over time and between different forms of administration.
The IVI is a 32-item questionnaire developed to measure the impact of vision impairment on restriction of participation in daily activities in five domains of functioning. Each item is rated on a six-level scale from "no difficulty" to "can't do because of vision." The IVI was administered by trained interviewers to 115 people with impaired vision (visual acuity less than 6/12 or visual field deficit) who attended the Royal Victorian Eye and Ear Hospital, a vision rehabilitation agency, or a self-help group for people with impaired vision. Data were also collected on demographic characteristics of participants, cause of vision impairment, and distance and near vision. General health status was assessed with the Short Form-12 (SF-12) of the Physical and Mental Health Summary Scales. A subset of participants completed the IVI twice, either 1 to 2 weeks apart or by different forms of administration (different interviewers or self).
Internal consistency of total and domain average IVI scores was high (alpha = 0.80-0.96) and sequential elimination of items did not affect consistency. Total and domain average IVI scores correlated moderately with both near and distance vision (r = 0.21-0.31) but did not correlate with physical or general health or comorbidity. Total and domain average IVI scores correlated most closely with global measures of restriction of participation (r = 0.44-0.82). Principal-components analysis confirmed that all IVI items contribute to one underlying theme and tended to confirm two of the five domains: emotional reaction to vision loss and mobility. The first three components explained 43%, 8%, and 6% of the variation in the data. Guttman split-half reliability coefficients between different forms of administration and over time ranged from 0.73 to 0.94 for domain and total IVI scores. Mean absolute difference for domain and total scores between administrations was less than 1 step for all domains and the total score.
This study provides support that the IVI has sufficient internal and construct validity to measure the effect of vision impairment on restriction of participation in daily activities. The IVI demonstrates acceptable reliability over a short period and yields consistent results between interviewers. The IVI can also be self-administered with assurance that the results will be comparable to those that would have been obtained by a trained interviewer. Therefore, the psychometric characteristics of the IVI support its use in assessment of the vision rehabilitation needs of people with impaired vision. Its stability over time indicates that it has potential to evaluate outcomes of intervention.
Investigative Ophthalmology & Visual Science 05/2002; 43(4):927-35. · 3.60 Impact Factor
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ABSTRACT: To obtain statements describing the impact of vision impairment on participation in every day activities of school-aged children (8-18 years) capturing their opinion, as the primary step in developing a pediatric vision-related quality of life instrument.
Separate focus groups for students with low vision, parents and teachers plus in-depth individual interviews were conducted in Victoria, Australia. Focus groups followed a topic guide, were digitally audio recorded and transcribed verbatim. Statements were identified, coded and ascribed into major themes.
102 participants provided just over 2600 statements (an average of 146 statements per verbatim transcript) which were classified into 5 themes: school/specialist instruction, social interaction, family, community and vision impairment peer interaction. The identified areas likely to facilitate good participation in every day activities, and accounted for 79% of the statements were class teacher knowledge and specialist support (40%) and social interaction (39%). The student perspective focused on communication skills and orientation and mobility whereas the specialist instructors' emphasis was on specialist support. Emphases across the themes varied between focus groups and highlight the benefit of including the perspectives of all stakeholders in questionnaire design.
The multi-perspective development strategy for a new questionnaire has established that it is crucial to integrate different stakeholders' perspectives. By doing so, it will be possible to develop a balanced questionnaire.
Ophthalmic epidemiology 15(2):114-20. · 1.93 Impact Factor
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ABSTRACT: To describe the methods and innovations used in constructing the VisQoL, a vision-related utility instrument for the health economic evaluation of eye care and rehabilitation programs.
The VisQoL disaggregates vision into six items. Utilities were estimated for item worst responses (the worst level for each item, with all other items at their best level) and VisQoL all-worst responses (all items at their worst level) using the time trade-off procedure. Time trade-off questions require people to imagine living a fixed number of years with a particular health condition and then indicate how many of those years of life they would be willing to trade to have perfect health. Where respondents indicated a health state was "worse than death" negative utilities were estimated. Time trade-off questions minimized the "focusing effect," which occurs if respondents discount the fact that all other aspects of health are at their best when answering questions, by using pictorial and verbal aids.
Item utilities were combined using a multiplicative model, and VisQoL model utilities placed on a scale where 0.00 and 1.00 represent full health and death, respectively. The VisQoL allows utilities to be calculated for a wide range of vision-related conditions.
The 6-item VisQoL has excellent psychometric properties and is specifically designed to be sensitive to vision-related quality of life. It is the first instrument to permit the rapid estimation of utility values for use in economic evaluations of vision-related programs.
Ophthalmic epidemiology 15(4):218-23. · 1.93 Impact Factor
