Joshua Foreman

Recruitment and Testing Protocol in the National Eye Health Survey: A Population-Based Eye Study in Australia

ABSTRACT Purpose: To present the recruitment and testing methodology of the National Eye Health Survey (NEHS), a population-based study that aimed to determine the prevalence and causes of vision impairment and blindness in Australia. Methods: Non-Indigenous Australians aged 50 years and older and Indigenous Australians aged 40 years and older were recruited using a door-to-door approach from 30 randomly selected geographical areas, stratified by remoteness. Participants underwent a vision examination, anterior segment assessment, intraocular pressure testing, perimetry, and fundus photography. Results: In total, recruiters approached 23,235 residences, and 11,883 residents were successfully contacted (51.1%). Of these, 6760 (56.9%) were deemed eligible and 5764 agreed to participate (positive response rate = 85.3%). Of those who agreed, 4836 residents attended the examination (4836/6760 = 71.5%). This included 1738 Indigenous Australians (41.1% male) aged 40–92 years (mean ± standard deviation = 55.0 ± 10.0 years) and 3098 non-Indigenous Australians (46.4% male), aged 50–98 years (mean ± standard deviation = 66.6 ± 9.7 years). Conclusions: The NEHS achieved an excellent positive response rate, and the data collected from 4836 Australians will provide the first population-based national estimate of the prevalence of vision impairment and blindness. This data will guide future economic analysis, policy formulation, and eye health service delivery in Australia.

Sampling methodology and site selection in the National Eye Health Survey (NEHS): an Australian population-based prevalence study

This paper presents the sampling methodology of the National Eye Health Survey that aimed to determine the prevalence of vision impairment and blindness in Australia.

The Prevalence and Causes of Vision Loss in Indigenous and Non-Indigenous Australians: The National Eye Health Survey

PURPOSE To conduct a nationwide survey on the prevalence and causes of vision loss in Indigenous and non-Indigenous Australians. DESIGN Nationwide, cross-sectional, population-based survey. PARTICIPANTS Indigenous Australians aged 40 years or older and non-Indigenous Australians aged 50 years and older. METHODS Multistage random-cluster sampling was used to select 3098 non-Indigenous Australians and 1738 Indigenous Australians from 30 sites across 5 remoteness strata (response rate of 71.5%). Sociodemographic and health data were collected using an interviewer-administered questionnaire. Trained examiners conducted standardized eye examinations, including visual acuity, perimetry, slit-lamp examination, intraocular pressure, and fundus photography. The prevalence and main causes of bilateral presenting vision loss (visual acuity <6/12 in the better eye) were determined, and risk factors were identified. MAIN OUTCOME MEASURES Prevalence and main causes of vision loss. RESULTS The overall prevalence of vision loss in Australia was 6.6% (95% confidence interval [CI], 5.4-7.8). The prevalence of vision loss was 11.2% (95% CI, 9.5-13.1) in Indigenous Australians and 6.5% (95% CI, 5.3-7.9) in non-Indigenous Australians. Vision loss was 2.8 times more prevalent in Indigenous Australians than in non-Indigenous Australians after age and gender adjustment (17.7%, 95% CI, 14.5-21.0 vs. 6.4%, 95% CI, 5.2-7.6, P < 0.001). In non-Indigenous Australians, the leading causes of vision loss were uncorrected refractive error (61.3%), cataract (13.2%), and age-related macular degeneration (10.3%). In Indigenous Australians, the leading causes of vision loss were uncorrected refractive error (60.8%), cataract (20.1%), and diabetic retinopathy (5.2%). In non-Indigenous Australians, increasing age (odds ratio [OR], 1.72 per decade) and having not had an eye examination within the past year (OR, 1.61) were risk factors for vision loss. Risk factors in Indigenous Australians included older age (OR, 1.61 per decade), remoteness (OR, 2.02), gender (OR, 0.60 for men), and diabetes in combination with never having had an eye examination (OR, 14.47). CONCLUSIONS Vision loss is more prevalent in Indigenous Australians than in non-Indigenous Australians, highlighting that improvements in eye healthcare in Indigenous communities are required. The leading causes of vision loss were uncorrected refractive error and cataract, which are readily treatable. Other countries with Indigenous communities may benefit from conducting similar surveys of Indigenous and non-Indigenous populations.

Original articleThe Prevalence and Causes of Vision Loss in Indigenous and Non-Indigenous Australians: The National Eye Health Survey

PURPOSE To conduct a nationwide survey on the prevalence and causes of vision loss in Indigenous and non-Indigenous Australians. DESIGN Nationwide, cross-sectional, population-based survey. PARTICIPANTS Indigenous Australians aged 40 years or older and non-Indigenous Australians aged 50 years and older. METHODS Multistage random-cluster sampling was used to select 3098 non-Indigenous Australians and 1738 Indigenous Australians from 30 sites across 5 remoteness strata (response rate of 71.5%). Sociodemographic and health data were collected using an interviewer-administered questionnaire. Trained examiners conducted standardized eye examinations, including visual acuity, perimetry, slit-lamp examination, intraocular pressure, and fundus photography. The prevalence and main causes of bilateral presenting vision loss (visual acuity <6/12 in the better eye) were determined, and risk factors were identified. MAIN OUTCOME MEASURES Prevalence and main causes of vision loss. RESULTS The overall prevalence of vision loss in Australia was 6.6% (95% confidence interval [CI], 5.4-7.8). The prevalence of vision loss was 11.2% (95% CI, 9.5-13.1) in Indigenous Australians and 6.5% (95% CI, 5.3-7.9) in non-Indigenous Australians. Vision loss was 2.8 times more prevalent in Indigenous Australians than in non-Indigenous Australians after age and gender adjustment (17.7%, 95% CI, 14.5-21.0 vs. 6.4%, 95% CI, 5.2-7.6, P < 0.001). In non-Indigenous Australians, the leading causes of vision loss were uncorrected refractive error (61.3%), cataract (13.2%), and age-related macular degeneration (10.3%). In Indigenous Australians, the leading causes of vision loss were uncorrected refractive error (60.8%), cataract (20.1%), and diabetic retinopathy (5.2%). In non-Indigenous Australians, increasing age (odds ratio [OR], 1.72 per decade) and having not had an eye examination within the past year (OR, 1.61) were risk factors for vision loss. Risk factors in Indigenous Australians included older age (OR, 1.61 per decade), remoteness (OR, 2.02), gender (OR, 0.60 for men), and diabetes in combination with never having had an eye examination (OR, 14.47). CONCLUSIONS Vision loss is more prevalent in Indigenous Australians than in non-Indigenous Australians, highlighting that improvements in eye healthcare in Indigenous communities are required. The leading causes of vision loss were uncorrected refractive error and cataract, which are readily treatable. Other countries with Indigenous communities may benefit from conducting similar surveys of Indigenous and non-Indigenous populations.

Adherence to diabetic eye examination guidelines in Australia: the National Eye Health Survey.

Objective: To determine adherence to NHMRC eye examination guidelines for Indigenous and non‐Indigenous Australian people with diabetes.

Treatment coverage rates for refractive error in the National Eye Health survey

Objective To present treatment coverage rates and risk factors associated with uncorrected refractive error in Australia. Methods Thirty population clusters were randomly selected from all geographic remoteness strata in Australia to provide samples of 1738 Indigenous Australians aged 40 years and older and 3098 non-Indigenous Australians aged 50 years and older. Presenting visual acuity was measured and those with vision loss (worse than 6/12) underwent pinhole testing and hand-held auto-refraction. Participants whose corrected visual acuity improved to be 6/12 or better were assigned as having uncorrected refractive error as the main cause of vision loss. The treatment coverage rates of refractive error were calculated (proportion of participants with refractive error that had distance correction and presenting visual acuity better than 6/12), and risk factor analysis for refractive correction was performed. Results The refractive error treatment coverage rate in Indigenous Australians of 82.2% (95% CI 78.6–85.3) was significantly lower than in non-Indigenous Australians (93.5%, 92.0–94.8) (Odds ratio [OR] 0.51, 0.35–0.75). In Indigenous participants, remoteness (OR 0.41, 0.19–0.89 and OR 0.55, 0.35–0.85 in Outer Regional and Very Remote areas, respectively), having never undergone an eye examination (OR 0.08, 0.02–0.43) and having consulted a health worker other than an optometrist or ophthalmologist (OR 0.30, 0.11–0.84) were risk factors for low coverage. On the other hand, speaking English was a protective factor (OR 2.72, 1.13–6.45) for treatment of refractive error. Compared to non-Indigenous Australians who had an eye examination within one year, participants who had not undergone an eye examination within the past five years (OR 0.08, 0.03–0.21) or had never been examined (OR 0.05, 0.10–0.23) had lower coverage. Conclusion Interventions that increase integrated optometry services in regional and remote Indigenous communities may improve the treatment coverage rate of refractive error. Increasing refractive error treatment coverage rates in both Indigenous and non-Indigenous Australians through at least five-yearly eye examinations and the provision of affordable spectacles will significantly reduce the national burden of vision loss in Australia.

The validity of self-report of eye diseases in participants with vision loss in the National Eye Health Survey

We assessed the validity and reliability of self-report of eye disease in participants with unilateral vision loss (presenting visual acuity worse than 6/12 in the worse eye and equal to or better than 6/12 in the better eye) or bilateral vision loss (presenting visual acuity worse than 6/12 in the better eye) in Australia’s National Eye Health Survey. In total, 1738 Indigenous Australians and 3098 non-Indigenous Australians were sampled from 30 sites. Participants underwent a questionnaire and self-reported their eye disease histories. A clinical examination identified whether participants had cataract, age-related macular degeneration, diabetic retinopathy and glaucoma. For those identified as having unilateral or bilateral vision loss (438 Indigenous Australians and 709 non-Indigenous Australians), self-reports were compared with examination results using validity and reliability measures. Reliability was poor for all four diseases (Kappa 0.06 to 0.37). Measures of validity of self-report were variable, with generally high specificities (93.7% to 99.2%) in all diseases except for cataract (63.9 to 73.1%) and low sensitivities for all diseases (7.6% in Indigenous Australians with diabetic retinopathy to 44.1% of non-Indigenous Australians with cataract). This study suggests that self-report is an unreliable population-based research tool for identifying eye disease in those with vision loss.

Participant referral rate in the National Eye Health Survey (NEHS)

Purpose To present the rates of referral of participants in the National Eye Health Survey (NEHS) for further eye care. Materials & methods A national sample of 3098 non-Indigenous Australians aged 50–98 and 1738 Indigenous Australians aged 40–92 years living in 30 randomly selected sites was recruited using a door-to-door approach. Participants completed a general questionnaire and a series of eye tests, including vision and anterior segment assessment, intra-ocular pressure measurement, visual field testing and fundus photography. A predefined protocol was used to guide the referral of participants for follow up eye care. An ophthalmologist was on-call to assist with the triaging of participants. Results Of the total sample, 32.1% (994/3098) of non-Indigenous participants and 43.6% (757/1738) of Indigenous participants were referred for further eye care (p<0.001). A significant difference in referral rates for Indigenous Australians was observed between regions of differing geographic remoteness [range = 32.2% (Inner Regional)—60.4% (Very Remote), p <0.001]. After adjusting for covariates, males (OR = 1.24, 95% CI: 1.06–1.46), older age (OR = 1.02 per year, 95% CI: 1.01, 1.02) and longer time since previous eye examination (OR = 1.15 per year, 95% CI: 1.12, 1.19) were associated with higher rates of eye care referral in the non-Indigenous population. In the Indigenous population, older age (OR = 1.02 per year, 95% CI: 1.01–1.03), self-reported diabetes (OR = 1.70, 95% CI: 1.37–2.12), greater geographical remoteness (OR = 1.19, 95% CI: 1.09–1.29) and longer time since previous eye examination (OR = 1.10 per year, 95% CI: 1.07, 1.13) were associated with a higher rate of referral after multivariate adjustments. A total of 25 participants (1.4%) were referred for urgent follow-up of potentially sight threatening conditions. Conclusions Our data has identified several high risk groups that required ophthalmic referral including older Australians, non-Indigenous men, Indigenous Australians with self-reported diabetes and those residing in very remote populations who may benefit from improvements in the provision and/or uptake of eye health services. Future longitudinal research is warranted to evaluate the feasibility and efficacy of implementing a referral protocol within a population-based research setting.

The Prevalence of Self-Reported Diabetes in the Australian National Eye Health Survey

Objective To present the prevalence of self-reported diabetes in Indigenous and non-Indigenous participants in the National Eye Health Survey. Research Design and Methods 3098 non-Indigenous Australians aged 50–98 years and 1738 Indigenous Australians aged 40–92 years were examined in 30 randomly selected sites, stratified by remoteness. A history of diabetes was obtained using an interviewer-administered questionnaire. Results 13.91% (431/3098) of non-Indigenous Australians and 37.11% (645/1738) of Indigenous Australians had self-reported diabetes. The age-adjusted prevalence of self-reported diabetes for non-Indigenous and Indigenous Australians was 11.49% and 43.77%, respectively (p <0.001). The prevalence of self-reported diabetes increased markedly with age (OR = 1.04 per year, p = 0.017). Indigenous Australians living in very remote areas were more likely to have self-reported diabetes than those in major city areas (OR = 1.61, p = 0.038). Conclusions The prevalence of self-reported diabetes in Australia was high, with the prevalence being almost 4 times higher in Indigenous Australians compared with non-Indigenous Australians. With the prevalence of diabetes likely to increase, the results of this national survey may inform future policy, planning and funding allocation to assist in controlling the diabetes epidemic.

Prevalence of Age-Related Macular Degeneration in Australia: The Australian National Eye Health Survey

Importance Age-related macular degeneration (AMD) is a leading cause of irreversible blindness among the elderly population globally. Currently, knowledge of the epidemiology of AMD in Australia remains scarce because of a paucity of recent population-based data. Objective To examine the prevalence of AMD in Australia. Design, Setting, and Participants In this population-based, cross-sectional survey performed from March 11, 2015, to April 18, 2016, a sample of 3098 nonindigenous Australians 50 years and older and 1738 indigenous Australians 40 years and older from 30 geographic areas across Australia were examined. Main Outcomes and Measures Any AMD, early AMD, intermediate AMD, and late AMD graded according to the Beckman clinical classification system. Results A total of 4836 individuals were examined, including 3098 nonindigenous Australian (64.1%; 58.9% female vs 41.1% male; age range, 40-92 years; mean [SD] age, 55.0 [10.0] years) and 1738 indigenous Australians (35.9%; 53.6% female vs 46.4% male; age range, 50-98 years; mean [SD] age, 66.6 [9.7] years). A total of 4589 (94.9%, 2946 nonindigenous and 1643 indigenous) participants had retinal photographs in at least 1 eye that were gradable for AMD. The weighted prevalence of early AMD was 14.8% (95% CI, 11.7%-18.6%) and of intermediate AMD was 10.5% (95% CI, 8.3%-13.1%) among nonindigenous Australians. In indigenous Australians, the weighted prevalence of early AMD was 13.8% (95% CI, 9.7%-19.3%) and of intermediate AMD was 5.7% (96% CI, 4.7%-7.0%). Late AMD was found in 0.96% (95% CI, 0.59%-1.55%) of nonindigenous participants (atrophic, 0.72%; neovascular, 0.24%). The prevalence of late AMD increased to 6.7% in participants 80 years or older and was higher in men (1.4% vs 0.61%, P = .02). Only 3 (0.17% [95% CI, 0.04%-0.63%]) indigenous participants had late (atrophic) AMD. Age-related macular degeneration was attributed as the main cause of vision loss (<6/12 in the better eye) in 23 of 208 nonindigenous Australians (11.1%) and 2 of 183 indigenous Australians (1.1%). Conclusions and Relevance In line with data from other white populations, AMD is a prominent cause of vision loss in the nonindigenous Australian population. An increased provision of low vision rehabilitation services may be required to cope with the projected increase in AMD in Australia.