Estimating the global cost of vision impairment and its major causes: protocol for a systematic review.
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ABSTRACT: Introduction
Vision impairment (VI) places a burden on individuals, health systems and society in general. In order to support the case for investing in eye health services, an updated cost of illness study that measures the global impact of VI is necessary. To perform such a study, a systematic review of the literature is needed. Here we outline the protocol for a systematic review to describe and summarise the costs associated with VI and its major causes.Methods and analysis
We will systematically search in Medline (Ovid) and the Centre for Reviews and Dissemination database which includes the National Health Service Economics Evaluation Database. No language or geographical restriction will be applied. Additional literature will be identified by reviewing the references in the included studies and by contacting field experts. Grey literature will be considered. The review will include any study published from 1 January 2000 to November 2019 that provides information about costs of illness, burden of disease and/or loss of well-being in participants with VI due to an unspecified cause or due to one of the seven leading causes globally.Two reviewers will independently screen studies and extract relevant data from included studies. Methodological quality of economic studies will be assessed based on the British Medical Journal checklist for economic submissions adapted to costs of illness studies. This protocol has been prepared following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis protocols and has been published prospectively in Open Science Framework.Ethics and dissemination
Formal ethical approval is not required, as primary data will not be collected in this review. The findings of this study will be disseminated through peer-reviewed publications, stakeholder meetings and inclusion in the ongoing Lancet Global Health Commission on Global Eye Health. REGISTRATION DETAILS: https://osf.io/9au3w (DOI 10.17605/OSF.IO/6F8VM).
SUBMITTER: Marques AP
PROVIDER: S-EPMC7476478 | biostudies-literature | 2020 Sep
REPOSITORIES: biostudies-literature
Publications
Estimating the global cost of vision impairment and its major causes: protocol for a systematic review.
Marques Ana Patricia AP Ramke Jacqueline J Cairns John J Butt Thomas T Zhang Justine H JH Faal Hannah B HB Taylor Hugh H Jones Iain I Congdon Nathan N Bastawrous Andrew A Braithwaite Tasanee T Jovic Marty M Resnikoff Serge S Nandakumar Allyala A Khaw Peng Tee PT Bourne Rupert R A RRA Gordon Iris I Frick Kevin K Burton Matthew J MJ
BMJ open 20200906 9
<h4>Introduction</h4>Vision impairment (VI) places a burden on individuals, health systems and society in general. In order to support the case for investing in eye health services, an updated cost of illness study that measures the global impact of VI is necessary. To perform such a study, a systematic review of the literature is needed. Here we outline the protocol for a systematic review to describe and summarise the costs associated with VI and its major causes.<h4>Methods and analysis</h4>W ...[more]
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Project description:Vision impairment (VI) can have wide ranging economic impact on individuals, households, and health systems. The aim of this systematic review was to describe and summarise the costs associated with VI and its major causes. We searched MEDLINE (16 November 2019), National Health Service Economic Evaluation Database, the Database of Abstracts of Reviews of Effects and the Health Technology Assessment database (12 December 2019) for partial or full economic evaluation studies, published between 1 January 2000 and the search dates, reporting cost data for participants with VI due to an unspecified cause or one of the seven leading causes globally: cataract, uncorrected refractive error, diabetic retinopathy, glaucoma, age-related macular degeneration, corneal opacity, trachoma. The search was repeated on 20 January 2022 to identify studies published since our initial search. Included studies were quality appraised using the British Medical Journal Checklist for economic submissions adapted for cost of illness studies. Results were synthesized in a structured narrative. Of the 138 included studies, 38 reported cost estimates for VI due to an unspecified cause and 100 reported costs for one of the leading causes. These 138 studies provided 155 regional cost estimates. Fourteen studies reported global data; 103/155 (66%) regional estimates were from high-income countries. Costs were most commonly reported using a societal (n = 48) or healthcare system perspective (n = 25). Most studies included only a limited number of cost components. Large variations in methodology and reporting across studies meant cost estimates varied considerably. The average quality assessment score was 78% (range 35-100%); the most common weaknesses were the lack of sensitivity analysis and insufficient disaggregation of costs. There was substantial variation across studies in average treatment costs per patient for most conditions, including refractive error correction (range $12-$201 ppp), cataract surgery (range $54-$3654 ppp), glaucoma (range $351-$1354 ppp) and AMD (range $2209-$7524 ppp). Future cost estimates of the economic burden of VI and its major causes will be improved by the development and adoption of a reference case for eye health. This could then be used in regular studies, particularly in countries with data gaps, including low- and middle-income countries in Asia, Eastern Europe, Oceania, Latin America and sub-Saharan Africa.
| S-EPMC8943414 | biostudies-literature
Project description:Introduction: As the prevalence of age-related sensory impairment increases, more evidence emerges on the association between uni-sensory and cognitive impairment (CI) in older adults. However, the link between CI and concurrent hearing and vision impairment (referred to as dual sensory impairment/DSI) is not well-understood, and this combined effect may be additive or multiplicative. Moreover, the existing evidence on CI in older adults with DSI is scattered and limited. Through this systematic scoping review, we aim to map existing evidence on CI in older adults with DSI, and to summarize what is known about the prevalence, incidence and risk factors of CI, and tools used to screen or assess CI in older adults with DSI. Methods and Analysis: We will use the Joanna Briggs Institute framework to perform the review. Eleven databases [MEDLINE, CINAHL/EBSCO, EMBASE, Mednar, WorldWideScience, PsycEXTRA, OAIster, OpenGrey (SIGLE), Global Health, PsycINFO, and Web of Science] and clinical trial registries (ISRCTN Registry, WHO ICTRP, and ClinicalTrials.gov) will be searched. Study selection will be completed using Covidence, and data will be extracted using an a priori data extraction tool. To be included, studies had to be peer-reviewed, had older adults with DSI as the focal population, and are related to CI. Data will be presented using a narrative summary with emphasis on implications for future research and practice. Discussion: Reliable cognitive screening is of the utmost importance for prevention and treatment of CI within DSI population. The study findings will have significant implications for health services delivery and policy research. The summarized findings on the prevalence, incidence, associated risk factors, and CI screening and assessment tools will inform geriatric care. The review will also document knowledge gaps on CI in the DSI population and identify areas of interest for future studies. Ethics and Dissemination: The scoping study, being a review of existing documents, does not require ethics approval. The findings will be disseminated with relevant stakeholders using knowledge translation activities such as scientific presentations and publications. We intend to use the findings to conduct a Delphi study to evaluate which CI tools are suitable for older population with DSI.
| S-EPMC8326366 | biostudies-literature
Project description:IntroductionDue to growth and ageing of the world's population, the number of individuals worldwide with vision impairment (VI) and blindness is projected to increase rapidly over the coming decades. VI and blindness are an important cause of years lived with disability. However, the association of VI and blindness with mortality, including the risk of bias in published studies and certainty of the evidence, has not been adequately studied in an up-to-date systematic review and meta-analysis.Methods and analysisThe planned systematic review and meta-analysis will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Databases, including MEDLINE Ovid, Embase Ovid and Global Health, will be searched for relevant studies. Two reviewers will then screen studies and review full texts to identify studies for inclusion. Data extraction will be performed, and for included studies, the risk of bias and certainty of the evidence will be assessed using the Grades of Recommendation, Assessment, Development and Evaluation approach. The prognostic factor in this study is visual function, which must have been measured using a standard objective ophthalmic clinical or research instrument. We will use standard criteria from WHO to categorise VI and blindness. All-cause mortality may be assessed by any method one or more years after baseline assessment of vision. Results from included studies will be meta-analysed according to relevant sections of the Meta-analysis Of Observational Studies in Epidemiology checklist.Ethics and disseminationThis review will only include published data; therefore, ethics approval will not be sought. The findings of this review and meta-analysis will be published in an open-access, peer-reviewed journal and will be included in the ongoing Lancet Global Health Commission on Global Eye Health.
| S-EPMC7311038 | biostudies-literature
Project description:IntroductionDriving is one of the main modes of transport with safe driving requiring a combination of visual, cognitive and physical skills. With population ageing, the number of people living with vision impairment is set to increase in the decades ahead. Vision impairment may negatively impact an individual's ability to safely drive. The association between vision impairment and motor vehicle crash involvement or driving participation has yet to be systematically investigated. Further, the evidence for the effectiveness of vision-related interventions aimed at decreasing crashes and driving errors has not been synthesised.Methods and analysisA search will be conducted for relevant studies on Medline (Ovid), EMBASE and Global Health from their inception to March 2020 without date or geographical restrictions. Two investigators will independently screen abstracts and full texts using Covidence software with conflicts resolved by a third investigator. Data extraction will be conducted on all included studies, and their quality assessed to determine the risk of bias using the Joanna Briggs Institute Critical Appraisal Tools. Outcome measures include crash risk, driving cessation and surrogate measures of driving safety (eg, driving errors and performance). The results of this review will be reported using the Preferred Reporting Items for Systematic Review and Meta-Analysis guideline. Meta-analysis will be undertaken for outcomes with sufficient data and reported following the Meta-analyses of Observational Studies in Epidemiology guideline. Where statistical pooling is not feasible or appropriate, narrative summaries will be presented following the Synthesis Without Meta-analysis in systematic reviews guideline.Ethics and disseminationThis review will only report on published data thus no ethics approval is required. Results will be included in the Lancet Global Health Commission on Global Eye Health, published in a peer-reviewed journal and presented at relevant conferences.Prospero registration numberCRD42020172153.
| S-EPMC7646345 | biostudies-literature
Project description:ObjectivesThere has been increasing epidemiological research examining the association between vision impairment (VI) and cognitive impairment and how poor vision may be a modifiable risk factor for cognitive decline. The objective of this systematic review is to synthesise the published literature on the association of VI with cognitive decline, cognitive impairment or dementia, to aid the development of interventions and guide public policies pertaining to the relationship between vision and cognition.MethodsA literature search was performed with Embase, Medline and Cochrane library databases from inception to March 2020, and included abstracts and articles published in peer-reviewed journals in English. Our inclusion criteria included publications that contained subjective/objective measures of vision and cognition, or a diagnosis of VI, cognitive impairment or dementia. Longitudinal or cross-sectional studies with ≥100 participants aged >50 years were included. The search identified 11 805 articles whose abstracts underwent screening by three teams of study authors. Data abstraction and quality assessment using the Effective Public Health Practice Project Quality Assessment Tool were performed by one author (NN). 10% of the articles underwent abstraction and appraisal by a second author (LA/VV), results were compared between both and were in agreement.Results110 full-text articles were selected for data extraction, of which 53 were cross-sectional, 43 longitudinal and 14 were case-control studies. The mean age of participants was 73.0 years (range 50-93.1). Ninety-one (83%) of these studies reported that VI was associated with cognitive impairment.ConclusionOur systematic review indicates that a majority of studies examining the vision-cognition relationship report that VI is associated with more cognitive decline, cognitive impairment or dementia among older adults. This synthesis supports the need for additional research to understand the mechanisms underlying the association between VI and cognitive impairment and to test interventions that mitigate the cognitive consequences of VI.
| S-EPMC8739068 | biostudies-literature
Project description:BackgroundThe number of individuals with vision impairment worldwide is increasing because of an ageing population. We aimed to systematically identify studies describing the association between vision impairment and mortality, and to assess the association between vision impairment and all-cause mortality.MethodsFor this systematic review and meta-analysis, we searched MEDLINE (Ovid), Embase, and Global Health database on Feb 1, 2020, for studies published in English between database inception and Feb 1, 2020. We included prospective and retrospective cohort studies that measured the association between vision impairment and all-cause mortality in people aged 40 years or older who were followed up for 1 year or more. In a protocol amendment, we also included randomised controlled trials that met the same criteria as for cohort studies, in which the association between visual impairment and mortality was independent of the study intervention. Studies that did not report age-adjusted mortality data, or that focused only on populations with specific health conditions were excluded. Two reviewers independently assessed study eligibility, extracted the data, and assessed risk of bias. We graded the overall certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations framework. We did a random-effects meta-analysis to calculate pooled maximally adjusted hazard ratios (HRs) for all-cause mortality for individuals with a visual acuity of <6/12 versus those with ≥6/12; <6/18 versus those with ≥6/18; <6/60 versus those with ≥6/18; and <6/60 versus those with ≥6/60.FindingsOur searches identified 3845 articles, of which 28 studies, representing 30 cohorts (446 088 participants) from 12 countries, were included in the systematic review. The meta-analysis included 17 studies, representing 18 cohorts (47 998 participants). There was variability in the methods used to assess and report vision impairment. Pooled HRs for all-cause mortality were 1·29 (95% CI 1·20-1·39) for visual acuity <6/12 versus ≥6/12, with low heterogeneity between studies (n=15; τ2=0·01, I2=31·46%); 1·43 (1·22-1·68) for visual acuity <6/18 versus ≥6/18, with low heterogeneity between studies (n=2; τ2=0·0, I2=0·0%); 1·89 (1·45-2·47) for visual acuity <6/60 versus ≥6/18 (n=1); and 1·02 (0·79-1·32) for visual acuity <6/60 versus ≥6/60 (n=2; τ2=0·02, I2=25·04%). Three studies received an assessment of low risk of bias across all six domains, and six studies had a high risk of bias in one or more domains. Effect sizes were greater for studies that used best-corrected visual acuity compared with those that used presenting visual acuity as the vision assessment method (p=0·0055), but the effect sizes did not vary in terms of risk of bias, study design, or participant-level factors (ie, age). We judged the evidence to be of moderate certainty.InterpretationThe hazard for all-cause mortality was higher in people with vision impairment compared with those that had normal vision or mild vision impairment, and the magnitude of this effect increased with more severe vision impairment. These findings have implications for promoting healthy longevity and achieving the Sustainable Development Goals.FundingWellcome Trust, Commonwealth Scholarship Commission, National Institutes of Health, Research to Prevent Blindness, the Queen Elizabeth Diamond Jubilee Trust, Moorfields Eye Charity, National Institute for Health Research, Moorfields Biomedical Research Centre, Sightsavers, the Fred Hollows Foundation, the Seva Foundation, the British Council for the Prevention of Blindness, and Christian Blind Mission.
| S-EPMC7966688 | biostudies-literature
Project description:BackgroundIn the absence of accessible, good quality eye health services and inclusive environments, vision loss can impact individuals, households and communities in many ways, including through increased poverty, reduced quality of life and reduced employment. We aimed to estimate the annual potential productivity losses associated with reduced employment due to blindness and moderate and severe vision impairment (MSVI) at a regional and global level.MethodsWe constructed a model using the most recent economic, demographic (2018) and prevalence (2020) data. Calculations were limited to the working age population (15-64 years) and presented in 2018 US Dollars purchasing power parity (ppp). Two separate models, using Gross Domestic Product (GDP) and Gross National Income (GNI), were calculated to maximise comparability with previous estimates.FindingsWe found that 160.7 million people with MSVI or blindness were within the working age and estimated that the overall relative reduction in employment by people with vision loss was 30.2%. Globally, using GDP we estimated that the annual cost of potential productivity losses of MSVI and blindness was $410.7 billion ppp (range $322.1 - $518.7 billion), or 0.3% of GDP. Using GNI, overall productivity losses were estimated at $408.5 billion ppp (range $320.4 - $515.9 billion), 0.5% lower than estimates using GDP.InterpretationThese findings support the view that blindness and MSVI are associated with a large economic impact worldwide. Reducing and preventing vision loss and developing and implementing strategies to help visually impaired people to find and keep employment may result in significant productivity gains.FundingMJB is supported by the Wellcome Trust (207472/Z/17/Z). JR's appointment at the University of Auckland is funded by the Buchanan Charitable Foundation, New Zealand. The Lancet Global Health Commission on Global Eye Health was supported by grants from The Queen Elizabeth Diamond Jubilee Trust, Moorfields Eye Charity (GR001061), NIHR Moorfields Biomedical Research Centre, The Wellcome Trust, Sightsavers, The Fred Hollows Foundation, The SEVA Foundation, The British Council for the Prevention of Blindness and Christian Blind Mission. The funders had no role in the design, conduct, data analysis of the study, or writing of the manuscript.
| S-EPMC8093883 | biostudies-literature
Project description:BackgroundVision impairment is a common disability that poses significant challenges to individuals' ability to perform activities essential for independent living, including activities of daily living (ADL) and instrumental activities of daily living (IADL). Despite extensive research, the extent and nature of these associations remain unclear, particularly across varying levels and types of vision impairment.ObjectivesThis meta-analysis aims to estimate associations between vision impairment and difficulties with ADL and IADL.MethodsWe conducted a systematic review of relevant literature from the inception of the databases to February 2024, using electronic database searches, including PubMed, MEDLINE (Ovid), EMBASE, Cochrane CENTRAL, and CDSR. The articles were screened for title and abstract and then for the full-text reports by two independent reviewers and study quality was appraised. Meta-analyses were performed using random effects models to calculate the pooled effect size, expressed as odds ratio (OR) with corresponding 95% confidence interval (CI) of each outcome.ResultsForty-six studies involving 210,960 participants were included. A positive large correlation between vision impairment and difficulties with ADL (Correlation coefficient [r] = 0.55, 95% CI 0.37-0.68, p = 0.001) and IADL (r = 0.60, 95% CI 0.49-0.69, p = 0.001) was shown. We also found that vision impairment was associated with difficulties in ADL (OR = 1.77, 95% CI 1.56-2.01, p < 0.0001) and IADL (OR = 1.96, 95% CI 1.68-2.30, p < 0.0001). Subgroup analysis revealed that moderate to severe impairment resulted in difficulties in ADL (OR = 1.78, 95% CI 1.43-2.21, p = 0.02) and IADL (OR = 1.86, 95% CI 1.57-2.20, p = 0.0003). Further, there was a significant association between mild to moderate vision impairment and difficulties in IADL (OR = 1.38, 95% CI 1.23-1.55, p < 0.0001). Greater impact was observed in individuals with near vision impairment compared to those with distance vision impairment. Near vision impairment was significantly associated with higher difficulties in ADL (OR = 1.77, 95% CI 1.57-2.01, p < 0.0001) and IADL (OR = 1.79, 95% CI 1.32-2.42, p < 0.0001). In contrast, distance vision impairment showed lower but still significant associations with IADL (OR = 1.19, 95% CI 1.05-1.34, p = 0.005) and a nonsignificant association with ADL (OR = 1.12, 95% CI 0.90-1.40, p = 0.30). Meta-regression analysis indicated that for every one-year increase in age, ADL performance decreased by an average of 0.0147 units (p < 0.001), while IADL performance declined at a slower rate of 0.0047 units/year (p = 0.031).ConclusionThe present systematic review and meta-analysis using several statistical methods indicates that vision impairment including near vision impairment, is associated with difficulties in ADL and IADL. Thus, vision impairment remains an urgent and increasingly important public health priority. These findings highlight the need for targeted measures to raise public health awareness to provide rehabilitation and eye care examination strategies to reduce the risk of developing disabilities in adults and the elderly who have vision impairment.
| S-EPMC11785307 | biostudies-literature
Project description:ObjectivesTo systematically investigate the associations between vision impairment and risk of motor vehicle crash (MVC) involvement, and evaluate vision-related interventions to reduce MVCs.DesignMedline (Ovid), EMBASE and Global Health electronic databases were systematically searched from inception to March 2022 for observational and interventional English-language studies. Screening, data extraction and appraisals using the Joanna Briggs Institute appraisal tools were completed by two reviewers independently. Where appropriate, measures of association were converted into risk ratios (RRs) or ORs for meta-analysis.ParticipantsDrivers of four-wheeled vehicles of all ages with no cognitive declines.Primary and secondary outcomesMVC involvement (primary) and driving cessation (secondary).Results101 studies (n=778 052) were included after full-text review. 57 studies only involved older drivers (≥65 years) and 85 were in high-income settings. Heterogeneity in the data meant that most meta-analyses were underpowered as only 25 studies, further split into different groups of eye diseases and measures of vision, could be meta-analysed. The limited evidence from the meta-analyses suggests that visual field defects (four studies; RR 1.51 (95% CI 1.23, 1.85); p<0.001; I2=46.79%), and contrast sensitivity (two studies; RR 1.40 (95% CI 1.08, 1.80); p=0.01, I2=0.11%) and visual acuity loss (five studies; RR 1.21 (95% CI 1.02, 1.43); p=0.03, I2=28.49%) may increase crash risk. The results are more inconclusive for available evidence for associations of glaucoma (five studies, RR 1.27 (95% CI 0.67, 2.42); p=0.47; I2=93.48%) and cataract (two studies RR 1.15 (95% CI 0.97, 1.36); p=0.11; I2=3.96%) with crashes. Driving cessation may also be linked with glaucoma (two studies; RR 1.62 (95% CI 1.20, 2.19); p<0.001, I2=22.45%), age-related macular degeneration (AMD) (three studies; RR 2.21 (95% CI 1.47, 3.31); p<0.001, I2=75.11%) and reduced contrast sensitivity (three studies; RR 1.30 (95% CI 1.05, 1.61); p=0.02; I2=63.19%). Cataract surgery halved MVC risk (three studies; RR 0.55 (95% CI 0.34, 0.92); p=0.02; I2=97.10). Ranibizumab injections (four randomised controlled trials) prolonged driving in persons with AMD.ConclusionImpaired vision identified through a variety of measures is associated with both increased MVC involvement and cessation. Cataract surgery can reduce MVC risk. Despite literature being highly heterogeneous, this review shows that detection of vision problems and appropriate treatment are critical to road safety.Prospero registration numberCRD42020172153.
| S-EPMC10423787 | biostudies-literature
Project description:We conducted a systematic review and meta-analysis to investigate whether depression is associated with vision impairment (VI) in population-based studies in adults. MEDLINE and EMBASE were searched, from inception to June 2020. Studies were included if they provided two-by-two data for calculating the OR of association between VI and depression, or crude and/or an adjusted odds ratio (OR) with a corresponding 95% confidence interval (CI) were reported. The proportion of VI and depression was also extracted. ORs were pooled using random-effect models, proportions were pooled using random intercepts logistic regression models. Overall, 29 articles (31 studies) were included: of those, 18 studies used survey data (622,312 participants), 10 used clinical examination data (69,178 participants), and 3 used administrative databases (48,162,290 participants). The proportion of depression (95%CI) was 0.17 (0.13-0.22) overall and 0.27 (0.21-0.33) in VI subjects. The proportion of VI was 0.10 (0.07-0.16) overall and 0.20 (0.13-0.29) in depressed subjects. The association between VI and depression was direct: crude ORs were 1.89 (1.51-2.37) for survey data, 2.17 (1.76-2.67) for clinical examination data, and 3.34 (1.01-11.11) for administrative databases; adjusted ORs were 1.75 (1.34-2.30), 1.59 (1.22-1.96), and 2.47 (0.97-6.33), respectively. In conclusion, VI and depression are prevalent morbidities and should be actively sought when either is identified, especially in older adults.
| S-EPMC9103717 | biostudies-literature