Nationwide Rapid Assessment of Avoidable Blindness (RAAB) in Armenia.

PURPOSE: This study aimed to estimate the prevalence and main causes of blindness and visual impairment in population aged 50 years and older in Armenia using Rapid Assessment of Avoidable Blindness (RAAB) methodology. METHODS: The study team randomly selected 50 clusters (each consisting of 50 people) from all 11 regions of Armenia. Data on participants' demographics, presenting visual acuity, pinhole visual acuity, principal cause of presenting visual acuity, spectacle coverage, uncorrected refractive error (URE), and presbyopia were collected using the RAAB survey form. Four teams of trained eye care professionals completed data collection in 2019. RESULTS: Overall, 2,258 people of 50 years and older participated in the study. The age- and gender- adjusted prevalence of bilateral blindness, severe and moderate visual impairment were 1.5% (95% CI: 1.0-2.1), 1.6% (95% CI: 1.0-2.2) and 6.6% (95% CI: 5.5-7.7), respectively.The main causes of blindness were cataract (43.9%) and glaucoma (17.1%). About 54.6% and 35.3% of participants had URE and uncorrected presbyopia, respectively. The prevalence of bilateral blindness and functional low vision increased with age and was the highest in participants 80 years and older. CONCLUSION: The rate of bilateral blindness was comparable with findings from countries that share similar background and confirmed that untreated cataract was the main cause of blindness. Given that cataract blindness is avoidable, strategies should be developed aiming to further increase the volume and quality of cataract care in Armenia.

Prevalence and secular trends of four causes of blindness and visual impairment in Iran (1990-2019): a comparative study based on the Global Burden of Disease project's data.

PURPOSE: The purpose of this study was to investigate the prevalence of cataracts, refractive disorders, age-related macular disease (AMD), and glaucoma, as well as their trends from 1990 to 2019 in Iran, in comparison with high-middle socio-demographic index (HMSDI) countries and the world, using the Global Burden of Disease (GBD) 2019 study. METHODS: The GBD study provided data on the prevalence of blindness and visual impairment (VI), as well as four of their causes including cataracts, refractive disorders, age-related macular disease (AMD), and glaucoma. Using Joinpoint analysis, the annual percent change (APC) was calculated to assess the trend of change in prevalence in each category of diseases from 1990 to 2019, stratified by sex and age, for Iran, HMSDI countries, and the world. RESULTS: In 2019, refractive errors and cataracts were the most common causes of blindness and VI for both genders in Iran, HMSDI countries and the world. Iran had a higher age-standardized prevalence in all four categories of ophthalmologic disorders compared to HMSDI countries and the world for both genders in 2019. Additionally, the age-specific prevalence of all four disorders in 2019 was higher in Iran compared to HMSDI countries. However, in terms of trends of prevalence from 1990 to 2019, the rate of reduction for the four ophthalmologic disorders in Iran was higher than in HMSDI and the world for both males and females. Furthermore, Iran had a greater percentage of reduction in prevalence for all age groups in all four disorders compared to HMSDI countries. CONCLUSION: The prevalence of cataracts, refractive errors, AMD, and glaucoma in Iran was higher compared to HMSDI countries in 2019 for both sexes and all age groups, but the trends of prevalence for all four disorders from 1990 to 2019 in Iran had a higher slope of reduction compared to HMSDI countries for all ages and sexes.

Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study.

BACKGROUND: Many causes of vision impairment can be prevented or treated. With an ageing global population, the demands for eye health services are increasing. We estimated the prevalence and relative contribution of avoidable causes of blindness and vision impairment globally from 1990 to 2020. We aimed to compare the results with the World Health Assembly Global Action Plan (WHA GAP) target of a 25% global reduction from 2010 to 2019 in avoidable vision impairment, defined as cataract and undercorrected refractive error. METHODS: We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. We fitted hierarchical models to estimate prevalence (with 95% uncertainty intervals [UIs]) of moderate and severe vision impairment (MSVI; presenting visual acuity from <6/18 to 3/60) and blindness (<3/60 or less than 10° visual field around central fixation) by cause, age, region, and year. Because of data sparsity at younger ages, our analysis focused on adults aged 50 years and older. FINDINGS: Global crude prevalence of avoidable vision impairment and blindness in adults aged 50 years and older did not change between 2010 and 2019 (percentage change -0·2% [95% UI -1·5 to 1·0]; 2019 prevalence 9·58 cases per 1000 people [95% IU 8·51 to 10·8], 2010 prevalence 96·0 cases per 1000 people [86·0 to 107·0]). Age-standardised prevalence of avoidable blindness decreased by -15·4% [-16·8 to -14·3], while avoidable MSVI showed no change (0·5% [-0·8 to 1·6]). However, the number of cases increased for both avoidable blindness (10·8% [8·9 to 12·4]) and MSVI (31·5% [30·0 to 33·1]). The leading global causes of blindness in those aged 50 years and older in 2020 were cataract (15·2 million cases [9% IU 12·7-18·0]), followed by glaucoma (3·6 million cases [2·8-4·4]), undercorrected refractive error (2·3 million cases [1·8-2·8]), age-related macular degeneration (1·8 million cases [1·3-2·4]), and diabetic retinopathy (0·86 million cases [0·59-1·23]). Leading causes of MSVI were undercorrected refractive error (86·1 million cases [74·2-101·0]) and cataract (78·8 million cases [67·2-91·4]). INTERPRETATION: Results suggest eye care services contributed to the observed reduction of age-standardised rates of avoidable blindness but not of MSVI, and that the target in an ageing global population was not reached. FUNDING: Brien Holden Vision Institute, Fondation Théa, The Fred Hollows Foundation, Bill & Melinda Gates Foundation, Lions Clubs International Foundation, Sightsavers International, and University of Heidelberg.

Prevalence and causes of vision loss in China from 1990 to 2019: findings from the Global Burden of Disease Study 2019.

BACKGROUND: Vision loss is an important public health issue in China, but a detailed understanding of national and regional trends in its prevalence and causes, which could inform health policy, has not been available. This study aimed to assess the prevalence, causes, and regional distribution of vision impairment and blindness in China in 1990 and 2019. METHODS: Data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used to estimate the prevalence of moderate and severe vision impairment and blindness in China and compare with other Group of 20 (G20) countries. We used GBD methodology to systematically analyse all available demographic and epidemiological data at the provincial level in China. We compared the age-standardised prevalences across provinces, and the changes in proportion of vision loss attributable to various eye diseases in 1990 and 2019. We used two different counterfactual scenarios with respect to population structure and age-specific prevalence to assess the contribution of population growth and ageing to trends in vision loss. FINDINGS: In 2019, the age-standardised prevalence was 2·57% (uncertainty interval [UI] 2·28-2·86) for moderate vision impairment, 0·25% (0·22-0·29) for severe vision impairment, and 0·48% (0·43-0·54) for blindness in China, which were all below the global average, but the prevalence of moderate and severe vision impairment had increased more rapidly than in other G20 countries from 1990 to 2019. The prevalence of vision loss increased with age, and the main causes of vision loss varied across age groups. The leading causes of vision impairment in China were uncorrected refractive error, cataract, and macular degeneration in both 1990 and 2019 in the overall population. From 1990 to 2019, the number of people with moderate vision impairment increased by 133·67% (from 19·65 to 45·92 million), those with severe vision impairment increased by 147·14% (from 1·89 to 4·67 million), and those with blindness increased by 64·35% (from 5·29 to 8·69 million); in each case, 20·16% of the increase could be explained by population growth. The contributions to these changes by population ageing were 87·22% for moderate vision impairment, 116·06% for severe vision impairment, and 99·22% for blindness, and the contributions by age-specific prevalence were 26·29% for moderate vision impairment, 10·91% for severe vision impairment, and -55·04% for blindness. The prevalence and specific causes of vision loss differed across provinces. INTERPRETATION: Although a comprehensive national policy to prevent blindness is in place, public awareness of visual health needs improving, and reducing the prevalence of moderate and severe vision impairment should be prioritised in future work. FUNDING: China National Key Research and Development Programme and Beijing Municipal Special Funds for Medical Research on Public Welfare Development and Reform.

Population Based Assessment of Prevalence and Causes of Vision Impairment in the North-eastern State of Tripura, India - The Tripura Eye Survey.

PURPOSE: To report the prevalence and causes of vision impairment (VI) in a population aged ≥40 years from a state-wide survey conducted in the northeastern state of Tripura, India. METHODS: A population-based cross-sectional study was undertaken where a sample of 4500 people was selected using cluster random sampling methodology. A team comprising of an optometrist and field workers visited the households and conducted the eye examination that included visual acuity assessment, anterior segment examination including lens and fundus examination. VI was defined as presenting visual acuity <6/18 in the better eye and it included moderate VI (<6/18 to 6/60), severe VI (<6/60 to 3/60) and blindness (<3/60). RESULTS: In all, 4109/4500 (91.3%) subjects were examined from 90 clusters. Among those examined, 49.1% were men and 39.6% had no education. The age and gender-adjusted prevalence of VI was 8.7% (95% CI: 7.8-9.6). The prevalence of moderate VI was 6.2% (95% CI: 5.5-7.0), Severe VI was 1.0 (95% CI: 0.7-1.3) and blindness was 1.5% (95% CI: 1.1-1.9). On applying multiple regression analysis, the odds of having VI were higher in older age groups and among women. Overall, cataract was the leading cause of VI (54.5%) followed by uncorrected refractive errors (39.6%). CONCLUSIONS: VI is common affecting nine out of every hundred people aged ≥40 years in the state of Tripura. Over 90% of which is due to avoidable causes such as cataract and uncorrected refractive errors. Provision of cataract surgery and spectacles may result in a substantial reduction in VI in Tripura.

Thirty Year Projected Magnitude (to 2050) of Near and Distance Vision Impairment and the Economic Impact if Existing Solutions are Implemented Globally.

Purpose: Recent global, regional and country-level prevalence estimates for blindness and vision impairment will be important when designing future public health policies. The aim of this paper is to contribute to this discussion by estimating the productivity impact of known effective interventions to treat all preventable cases of vision impairment at the global, regional and country-level up to 2050. We also provide estimates of potential reduction in the number of people with vision impairment, as well as averted vision-impaired years up to 2050.Methods: We combined recent estimates of the prevalence of blindness, distance and near vision impairment with the World Bank's World Development Indicators (WDI) and estimated the global, regional and country-level productivity gains up to 2030, 2040 and 2050 from known effective interventions, primarily cataract surgery and treated uncorrected refractive errors. The magnitude of productivity gains relative to baseline depended on population size, estimated current and future prevalence of vision impairment, level of economic development, long-term wage growth, and long-term real interest rates.Results: Globally, we estimate that the number of people affected by blindness could be reduced from the estimated 114.6 million by 2050 to 58.3 million. This would be associated with over one billion blind life-years averted and US$ 984 billion in global productivity gains. These numbers are dwarfed by the impact of interventions to reduce the prevalence of Moderate and Severe Vision Impairment (MSVI) [Presenting Acuity <20/60 to 20/400 in the better-seeing eye]. We estimate that the number of people affected by MSVI could be reduced by 435.8 million people to 147.9 million by 2050. This reduction would translate to over 9 billion MSVI -life-years avoided and US$ 17 trillion in productivity gains by 2050. While other causes of VI would not be possible to eliminate completely based on current known effective treatments, low-cost interventions to eliminate VI from uncorrected presbyopia would avert 1.2 billion presbyopia life-years and achieve US$ 1.05 trillion in productivity gains by 2050. In total, the global productivity gains for all three categories are estimated to be US$ 19 trillion by 2050. East Asia makes up the greatest share of productivity gains due to the high number of people affected by VI and the region's continuing economic growth.Conclusion: Implementation of currently known and effective treatments of avoidable blindness, MSVI and presbyopia would be expected to contribute significant productivity gains to the global economy at a fraction of the estimated costs to deliver them.

Diagnostic Accuracy of Rapid Assessment of Avoidable Blindness: A Population-based Assessment.

OBJECTIVES: To evaluate the diagnostic accuracy of rapid assessment of avoidable blindness (RAAB). DESIGN: Population-based diagnostic accuracy study. METHODS: A total of 2145 (95.3%, 2145/2250) subjects aged 50 years and older who participated in the RAAB survey were included. All the recruited participants underwent ophthalmic examination according to the RAAB protocol and then were reexamined with instruments in a mobile eye clinic set up in a village center on the same day. Examination in the mobile clinic included standardized visual acuity (VA) tests using logMAR charts, refraction, slit-lamp biomicroscopy, and dilated fundal examination with a binocular indirect ophthalmoscope. Blindness and economic blindness were defined as VA in the better-seeing eye <3/60 and <6/60, respectively. Visual impairment (VI) was defined as VA <6/18 in the better eye. The primary cause of blindness and VI was defined according to the cause of VI in the participant's better eye. MAIN OUTCOME MEASURES: The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and area under the curve (AUC) of receiver operating characteristics of RAAB for detection of blindness and the principal causes of VI. RESULTS: A total of 1816 subjects (84.7%), including 686 men (37.8%) and 1130 women (62.2%), underwent ophthalmic examination in the mobile eye clinic. The mean (±standard deviation) age was 64.4 ± 9.6 years. The sensitivities, specificities, AUC, PLR, and NLR of RAAB were 90.3%, 99.3%, 0.948, 124.0, and 0.10, respectively, for detection of blindness (presenting visual acuity, PVA <3/60); 89.5%, 98.7%, 0.940, 69.2, and 0.11, respectively, for detection of economic blindness (PVA <6/60); and 90.3%, 97.7%, 0.940, 38.7, and 0.10, respectively, for detection of VI (PVA <6/18). The sensitivities, specificities, AUC, PLR, and NLR were 90.5%, 98.1%, 0.943, 48.1, and 0.10; and 60.4%, 98.7%, 0.796, 46.4, and 0.40 for detection of VI (PVA <6/18) owing to cataract and refractive error, respectively. CONCLUSION: The diagnostic performances of RAAB were high for detecting the prevalence of blindness, VI, and VI owing to cataract.

Impact of a 10-Year Eye Care Program in Sokoto, Nigeria: Changing Pattern of Prevalence and Causes of Blindness and Visual Impairment.

BACKGROUND: This study was undertaken to ascertain the current magnitude and causes of blindness and visual impairment in persons aged 50 years and over and to assess the impact of a 10-year eye care program in Sokoto State, Nigeria. METHODS: A rapid assessment of avoidable blindness (RAAB) survey (in persons 50 years and over) was conducted in 2016. Participants were selected in Wurno health zone using a two-stage cluster randomized sampling with probability proportional to size. Operational definitions were based on RAAB and World Health Organization eye examination record definitions. Eye care program documents were reviewed and data from a baseline survey undertaken in 2005 were reanalyzed. RESULTS: A response of 89.1% (2405 of 2700 participants) was obtained in the 2016 survey. With available correction, the unadjusted prevalence of blindness was 7.7% (95% confidence interval [CI]: 6.4, 8.9). The odds of blindness were 1.8 times higher in females than males (95% CI: 1.3, 2.4; P < 0.001). Major causes of blindness were cataract (48.9%) corneal disease (20.1%), glaucoma (10.3%), and uncorrected refractive error/aphakia (8.7%). The age- and sex-adjusted prevalence of blindness has declined from 11.6% (95% CI: 7.4, 17.0) in 2005 to 6.8% (95% CI: 5.6, 8.0%) in 2016. CONCLUSION: The blindness prevalence is high, and the major causes are avoidable in the health zone. The findings suggest that investments in the program over the last 10 years might have led to almost a halving in the prevalence of blindness in th e population. However, the small sample size of persons 50+ years from Wurno zone in the 2005 survey necessitate caution when comparing the 2005 and the 2016 surveys.

Rapid Assessment of Avoidable Blindness: looking back, looking forward.

The Rapid Assessment of Avoidable Blindness, or RAAB, is a relatively simple and low-cost survey methodology to provide data on the prevalence and causes of visual loss. The aim of this article is to reflect on the achievements and challenges of RAAB, and to describe the future developments that are needed to ensure that it remains a relevant and widely used tool. To date, at least 331 RAABs have been undertaken in 79 countries, and these surveys provide an important source of information on visual loss at both the local and global level. A RAAB repository has been developed which includes the site and date of RAABs undertaken, and, where authors have agreed, the core indicators, reports or even raw data from the survey. This dataset has already been used for meta-analyses, and there are further opportunities for its use. Despite these achievements, there are core areas in which RAAB needs to be strengthened so that the full benefits of undertaking the survey can be reaped. Key developments of RAAB are underway, and will include greater use of mobile technologies using a cloud-based platform to enable both digital data collection, real-time survey reviews, reporting and analysis, and a greater emphasis on using the data for planning.

Blindness and Visual Impairment Profile and Rapid Assessment of Avoidable Blindness in South East Asia: Analysis of New Data. 2017 APAO Holmes Lecture.

PURPOSE: The International Agency for Prevention of Blindness (IAPB) South East Asia region (SEAR) that consists of 11 countries contains 26% of the world's population (1,761,000,000). In this region 12 million are blind and 78.5 million are visually impaired. This amounts to 30% of global blindness and 32% of global visual impairment. DESIGN: Rapid assessment of avoidable blindness (RAAB) survey analysis. METHODS: RAAB, either a repeat or a first time survey, was completed in 8 countries in this decade (2010 onwards). These include Bangladesh, Bhutan, India, Indonesia, Maldives, Sri Lanka, Thailand, and Timor Leste. RESULTS: Cataract is the principal cause of blindness and severe visual impairment in all countries. Refractive error is the principal cause of moderate visual impairment in 4 countries: Bangladesh, India, Maldives, and Sri Lanka; cataract continues to be the principal cause of moderate visual impairment in 4 other countries: Bhutan, Indonesia, Thailand, and Timor Leste. Outcome of cataract surgery is suboptimal in the Maldives and Timor Leste. CONCLUSIONS: Rigorous focus is necessary to improve cataract surgery outcomes and correction of refractive error without neglecting the quality of care. At the same time allowances must be made for care of the emerging causes of visual impairment and blindness such as glaucoma and posterior segment disorders, particularly diabetic retinopathy.

Pattern and Prevalence of Refractive Error and Secondary Visual Impairment in Patients Attending a Tertiary Hospital in Dhulikhel, Nepal.

Background Uncorrected refractive error is one of the most important causes of visual impairment worldwide. Objective To ascertain the pattern and prevalence of refractive error and secondary visual impairment in subjects attending Ophthalmology department. Method A prospective hospital-based study was designed where presenting visual acuity, age of presentation, refractive status, best corrected visual acuity and status of visual impairment were assessed in participants, ages ranging from 3-39 years presenting to the Ophthalmology department of Dhulikhel Hospital, Kathmandu University Hospital. History of use of spectacle was noted and participants were categorized into different visual impairment categories as per their presenting visual acuity. Result Out of a total of 4500 total clients examined during the study period, 388 (8.62%) had refractive error where 219 (56.44%) were females and 169 (43.56%) were males. Mean age at presentation was 22.70±7.69 years (range, 3-39 years). Astigmatism was the most common subtype seen in 373 eyes (48.06%), followed by myopia (366 eyes, 47.16%) and hypermetropia (31 eyes, 4.0%). Only 40.50% subjects who required refractive correction were using spectacle. 62.37% (242 clients) had some of visual impairment during their presentation. There was statistically significant improvement in visual acuity after refractive correction (p=0.00). Conclusion Uncorrected refractive error is one of the most important causes of visual impairment. Lack of awareness, infrequent ocular examination and lack of community or preschool vision screening were the main causes for the late presentation and significant visual impairment associated with the condition. Social stigma, economical limitation and negative counseling and attitudes about spectacle wear were primary factors behind the unsatisfactory spectacle use.

First Rapid Assessment of Avoidable Blindness Survey in the Maldives: Prevalence and Causes of Blindness and Cataract Surgery.

PURPOSE: A nationwide rapid assessment of avoidable blindness survey was undertaken in the Maldives among people aged 50 years or more to assess the prevalence and causes of blindness and visual impairment, cataract surgical coverage, cataract surgery outcome, and barriers to uptake of cataract surgical services. DESIGN: Prospective population-based study. METHODS: In the cluster sampling probability proportionate to size method, 3100 participants in 62 clusters across all 20 atolls were enrolled through house-to-house visits. They were examined in clusters by an ophthalmologist-led team. Data was recorded in mRAAB version 1.25 software on a smartphone. RESULTS: The age-sex standardized prevalence of blindness was 2.0% [95% confidence interval (CI), 1.5-2.6]. Cataract was the leading cause of blindness (51.4%) and uncorrected refractive error was the leading cause of visual impairment (50.9%). Blindness was more prevalent in higher age groups and women (16.3%). Cataract surgical coverage was 86% in cataract blind eyes and 93.5% in cataract blind persons. Good visual outcome in cataract operated eyes was 67.9% (presenting) and 76.6% (best corrected visual acuity). In this study, 48.1% of people had received cataract surgery in neighboring countries. Important barriers for not using the services were "did not feel the need" (29.7%) and "treatment deferred" (33.3%). CONCLUSIONS: Cataract surgical coverage is good, though nearly half the people received surgery outside the Maldives. Cataract surgery outcomes are below World Health Organization standards. Some barriers could be overcome with additional human resources and training to improve cataract surgical outcomes, which could encourage greater uptake of services within the country.

Prevalence of visual impairment due to uncorrected refractive error: Results from Delhi-Rapid Assessment of Visual Impairment Study.

AIM: To estimate the prevalence of visual impairment (VI) due to uncorrected refractive error (URE) and to assess the barriers to utilization of services in the adult urban population of Delhi. MATERIALS AND METHODS: A population-based rapid assessment of VI was conducted among people aged 40 years and above in 24 randomly selected clusters of East Delhi district. Presenting visual acuity (PVA) was assessed in each eye using Snellen's "E" chart. Pinhole examination was done if PVA was <20/60 in either eye and ocular examination to ascertain the cause of VI. Barriers to utilization of services for refractive error were recorded with questionnaires. RESULTS: Of 2421 individuals enumerated, 2331 (96%) individuals were examined. Females were 50.7% among them. The mean age of all examined subjects was 51.32 ± 10.5 years (standard deviation). VI in either eye due to URE was present in 275 individuals (11.8%, 95% confidence interval [CI]: 10.5-13.1). URE was identified as the most common cause (53.4%) of VI. The overall prevalence of VI due to URE in the study population was 6.1% (95% CI: 5.1-7.0). The elder population as well as females were more likely to have VI due to URE (odds ratio [OR] = 12.3; P < 0.001 and OR = 1.5; P < 0.02). Lack of felt need was the most common reported barrier (31.5%). CONCLUSIONS: The prevalence of VI due to URE among the urban adult population of Delhi is still high despite the availability of abundant eye care facilities. The majority of reported barriers are related to human behavior and attitude toward the refractive error. Understanding these aspects will help in planning appropriate strategies to eliminate VI due to URE.

Toward eliminating blindness due to uncorrected refractive errors: assessment of refractive services in the northern and central regions of Ghana.

PURPOSE: This study sought to document current refractive services in the northern and central regions of Ghana as a first step toward evidence-based planning of refractive services. METHODS: A descriptive cross-sectional survey was carried out in health facilities in the northern and central regions of Ghana, which provided eye-care services. A semi-structured questionnaire was administered to gather information on each facility type, human resources providing refractive services, assessment of refraction and spectacle dispensing output and provider barriers to the services. RESULTS: Current outputs of refraction in the northern and central regions were 0.5 and 1.2 per cent of the estimated refractive needs, respectively. Spectacle dispensing services were below the outputs of refraction. Lack of equipment (36.8 per cent) and cost of providing spectacles frames (31.6 per cent), were identified as the main barriers to providing refractive services. CONCLUSION: The provision of refractive services in the study regions was inadequate. Lack of infrastructure and inadequate human resource were the major reasons for the limited service provision. This should be considered for planning refractive services in the study regions and Ghana as a whole.

Visual impairment and spectacle coverage rate in Baoshan district, China: population-based study.

BACKGROUND: To investigate the prevalence and risk factors of visual impairment associated with refractive error and the unmet need for spectacles in a special suburban senior population in Baoshan District of Shanghai, one of several rural areas undergoing a transition from rural to urban area, where data of visual impairment are limited. METHODS: The study was a population based survey of 4545 Chinese aged (age: >60 years or older ) at Baoshan, Shanghai, in 2009. One copy of questionnaire was completed for each subject. Examinations included a standardized refraction and measurement of presenting and best corrected visual acuity (BCVA) as well as tonometry, slit lamp biomicroscopy, and fundus photography. RESULTS: The prevalence of mild (6/12 to 6/18), moderate (6/18 to 6/60) and severe visual impairment was 12.59%, 8.38% and 0.44%, respectively, and 5.26%, 3.06% and 0.09% with refractive correction. Visual impairment was associated with age, gender, education and career, but not insurance . The prevalence of correctable visual impairment was 5.81% (using 6/18 cutoff) and 13.18% (using 6/12 cutoff). Senior people and women were significantly at a higher risk of correctable visual impairment, while the well-educated on the contrary. The prevalence of undercorrected refractive error (improves by 2 or more lines with refraction) was 24.84%, and the proportion with undercorrected refractive error for mild, moderate , severe and no visual impairment was 61.54%, 67.98%, 60.00% and 14.10%, respectively. The spectacle coverage rate was 44.12%. Greater unmet need for spectacles was observed among elderly people, females, non-peasant, and subjects with less education and astigmatism only. CONCLUSIONS: High prevalence of visual impairment, visual impairment alleviated by refractive correction, and low spectacle coverage existed among the senior population in Baoshan District of Shanghai. Education for the public of the importance of regular examination and appropriate and accessible refraction service might be helpful to solve the problem.

Rapid assessment of avoidable blindness in two northern provinces of Burundi without eye services.

PURPOSE: To determine the prevalence and causes of blindness, severe visual impairment and visual impairment as well as cataract surgical coverage in two northern provinces of Burundi for the purpose of planning eye services. METHODS: The population-based Rapid Assessment of Avoidable Blindness survey methodology was used. RESULTS: Of 3800 people enrolled, 3684 (97%) were examined. The sample prevalences of blindness, severe visual impairment, and visual impairment were 1.1% (95% confidence interval, CI 0.8-1.4), 0.6% (95% CI 0.4-0.9), and 1.7% (95% CI 1.3-2.1), respectively. The leading causes of blindness were cataract (55%) and posterior segment causes (37%). Severe visual impairment was mainly due to cataract (43%) and refractive error (39%), and visual impairment was mainly due to refractive error (67%) and cataract (18%). Cataract surgical coverage by person at the level of <6/60 was 15%. CONCLUSIONS: The low prevalence of vision loss in this area with no eye services and a low cataract surgical coverage rate is surprising and possibly due to the effects of the previous years of conflict in which those with decreased vision may have been most likely to perish. If this explanation is correct, then Burundi needs to plan to deal with a markedly increasing prevalence of cataract in future.

Rapid assessment of avoidable blindness in the Occupied Palestinian Territories.

BACKGROUND: There are no recent data on the prevalence and causes of blindness in the Occupied Palestinian Territories. The aim of our study was to estimate the prevalence and causes of blindness and visual impairment in the population aged 50 years and above in the Occupied Palestinian Territories using the Rapid Assessment of Avoidable Blindness (RAAB) survey method. METHODS AND FINDINGS: Clusters of 40 people who were 50 years and above were selected with probability proportionate to size using a multistage cluster random sampling method. Participants received a comprehensive ophthalmic examination in their homes, including visual acuity testing by one of three experienced ophthalmologists. The principal cause for visual loss was determined by an experienced ophthalmologist using portable diagnostic instruments. Information about previous cataract surgery, satisfaction with surgery and barriers to cataract surgery were collected. The prevalence of self-reported diabetes was also determined. The prevalence of bilateral blindness (VA<3/60 in the better eye with available correction) was 3.4% (95% CI: 2.7-4.0), 2.0% (95% CI: 1.4-2.5) for severe visual impairment (VA>or=3/60 and <6/60), and 7.4% (95% CI: 6.4-8.3) for visual impairment (VA>or=6/60 and <6/18). Avoidable causes (i.e. cataract, refractive error, aphakia, surgical complications, corneal scarring and phthysis) accounted for 80.0% of bilateral blindness, severe visual impairment (70.7%) and visual impairment (86.2%). Cataract was the main cause of blindness (55.0%). The prevalence of blindness was higher in Gaza (4.9%, 95% CI: 3.7-6.1%) than in the West Bank (2.5%, 95% CI: 1.9-3.1%) and among women (4.3%,95% CI: 3.3-5.2%) compared to men (2.2%,95%CI:1.5-2.9%). Among people who had undergone cataract surgery in the past, only 54.5% of eyes obtained a good outcome (VA>or=6/18), 23.2% had a borderline outcome (VA<6/18 and >or=6/60) and 22.3% had a poor outcome (VA<6/60) with available correction. The prevalence of self-reported diabetes mellitus in >or=50 year age group was 26.4% (95% CI: 24.9-27.9). CONCLUSIONS: The prevalence of blindness suggests that significant numbers of people in the Occupied Palestinian Territories exist who do not access eye care - predominantly women and those residing in Gaza. Programmes need to focus on maximizing the use of current services by these excluded groups.

Evidence that children with special needs all require visual assessment.

DESIGN: A protocol-based ophthalmological assessment was performed on-site by a skilled investigator. PATIENTS: Children attending schools for special needs in Glasgow were offered eye care within their school. Outcomes for the first 240 participants are reported. OUTCOME MEASURES: Number of children for whom visual acuity could be measured and the results of refraction. Results 228/240 (95%) children were able to co-operate in a complete or nearly complete assessment of visual function. Visual acuity could be reliably assessed in 190 children using a range of tests from preferential looking to logMAR charts. 23/190 (12.1%) were found to be visually impaired according to WHO criteria. 105/228 (46.1%) subjects were found to have a refractive error which required correction. 50/105 subjects were wearing an adequate correction (ie, difference of less than 0.75 D sphere or cylinder compared with the retinoscopy result obtained on screening) and 55 (24.1%) children were prescribed a new correction. The prevalence of all types of refractive error was found to be significantly higher in the population with special needs, in particular the learning disabilities subgroup, compared with normal children. High hyperopia and astigmatism were common. CONCLUSION: With patience, suitably adapted methods, a familiar environment and skill, visual assessment is feasible in the majority of children with special needs. The prevalence of reduced visual acuity is high and unaddressed correctable refractive error is a major cause.

Age-specific changes in the prevalence and management of optically correctable visual impairment between 1988 and 2000: the Ponza Eye Study.

PURPOSE: To obtain age-specific data on changes in the prevalence and management of optically correctable visual impairments (OCVIs) in Ponza, Italy. METHODS: Ophthalmologic examinations were carried out to 1000 Ponzans aged 40-87 years in 1988 and to 836 persons in 2000. Visual acuity (VA) was evaluated under uncorrected (VA(UC)), presenting (VA(PR)), and best-corrected (VA(BC)) conditions. We calculated the prevalence of total OCVIs (subjects with VA(UC)>0.5 logMAR and VA(BC)0.5 logMAR), and corrected OCVIs (VA(PR)

Prevalence and causes of visual impairment in low-middle income school children in Sao Paulo, Brazil.

PURPOSE: Assess prevalence and causes of vision impairment among low-middle income school children in São Paulo. METHODS: Cluster sampling was used to obtain a random sample of children ages 11 to 14 years from public schools (grades 5-8) in three districts from June to November 2005. The examination included visual acuity testing, ocular motility, and examination of the external eye, anterior segment, and media. Cycloplegic refraction and fundus examination were performed in children with uncorrected visual acuity 20/40 or worse in either eye. A principal cause of visual impairment was determined for eyes with uncorrected visual acuity of 20/40 or worse. RESULTS: A total of 2825 children were enumerated and 2441 (86.4%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity 20/40 or worse in the better eye was 4.82%, 2.67%, and 0.41%, respectively. Spectacles were used by 144 (5.9%) children. Refractive error was a cause in 76.8% of children with visual impairment in one or both eyes; amblyopia, 11.4%; retinal disorders, 5.9%; other causes, 2.7%; and unexplained causes, 7.7%. Myopic visual impairment (spherical equivalent -0.50 D in one or both eyes) was not associated with age or grade level, but female sex was marginally significant (P = 0.070). Hyperopic visual impairment (+2.00 D or more) was not associated with age, grade level, or sex. CONCLUSIONS: The prevalence of reduced vision in low-middle income urban São Paulo school children was low, most of it because of uncorrected refractive error. Cost-effective strategies are needed to address this easily treated cause of vision impairment.