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Leon B Ellwein - One of the best experts on this subject based on the ideXlab platform.
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prevalence of Refractive Error in the united states 1999 2004
Archives of Ophthalmology, 2008Co-Authors: Susan Vitale, Leon B Ellwein, Mary Frances Cotch, Frederick L Ferris, Robert D SperdutoAbstract:Objective To describe the prevalence of Refractive Error in the United States. Methods The 1999-2004 National Health and Nutrition Examination Survey (NHANES) used an autorefractor to obtain Refractive Error data on a nationally representative sample of the US noninstitutionalized, civilian population 12 years and older. Using data from the eye with a greater absolute spherical equivalent (SphEq) value, we defined clinically important Refractive Error as follows: hyperopia, SphEq value of 3.0 diopters (D) or greater; myopia, SphEq value of −1.0 D or less; and astigmatism, cylinder of 1.0 D or greater in either eye. Results Of 14 213 participants 20 years or older who completed the NHANES, Refractive Error data were obtained for 12 010 (84.5%). The age-standardized prevalences of hyperopia, myopia, and astigmatism were 3.6% (95% confidence interval [CI], 3.2%-4.0%), 33.1% (95% CI, 31.5%-34.7%), and 36.2% (95% CI, 34.9%-37.5%), respectively. Myopia was more prevalent in women (39.9%) than in men (32.6%) (P Conclusion Estimates based on the 1999-2004 NHANES vision examination data indicate that clinically important Refractive Error affects half of the US population 20 years or older.
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psychometric properties of the national eye institute Refractive Error quality of life instrument
Ophthalmology, 2003Co-Authors: Ron D Hays, Leon B Ellwein, Carol M Mangione, Anne S Lindblad, Karen Spritzer, Peter J McdonnellAbstract:Abstract Objective To estimate the psychometric properties of a vision-targeted measure of health-related quality of life, the National Eye Institute–Refractive Error Quality of Life survey (NEI-RQL), which includes 13 scales designed to assess the impact of Refractive Error and its correction on day-to-day life. Design Cross-sectional survey. Participants The NEI-RQL was self-administered by 667 myopes, 380 hyperopes, and 114 emmetropes recruited from the practices of 6 medical centers. All participants had near and distance visual acuity of 20/32 or better in the worse eye while benefiting from their current method for correction of Refractive Error (glasses, contact lens, Refractive surgery). Methods Mean scores, standard deviations, internal consistency reliability, and test–retest intraclass correlations were estimated for the NEI-RQL scales. Item discrimination was assessed by item–scale correlations. Construct validity was evaluated by assessing the sensitivity of scale scores to type of Refractive Error, type of Refractive Error correction, and spherical equivalent. Construct validity of the NEI-RQL was compared to those of the Medical Outcomes Study 36-item short-form health survey (SF-36) and the National Eye Institute Vision Functioning Questionnaire (NEI VFQ-25) in a random subsample of respondents. Main outcome measures The 13 NEI-RQL scales—clarity of vision, expectations, near vision, far vision, diurnal fluctuations, activity limitations, glare, symptoms, dependence on correction, worry, suboptimal correction, appearance, and satisfaction with correction. Results Emmetropes tended to score significantly better on the NEI-RQL scales than myopes and hyperopes. The method of Refractive Error correction was also associated with NEI-RQL scores. In addition, the NEI-RQL multi-item scales accounted for 29% of the variance in the NEI-RQL satisfaction with correction item beyond that explained by the SF-36 and the NEI VFQ-25. Conclusion These results support the reliability and construct validity of the NEI-RQL. The instrument appears to be useful for comparisons of people with different types of correction for Refractive Error.
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Refractive Error and visual impairment in african children in south africa
Investigative Ophthalmology & Visual Science, 2003Co-Authors: Kovin Naidoo, Gopal P Pokharel, Brien A Holden, Avesh Raghunandan, Khathutshelo P Mashige, Pirindhavellie Govender, Leon B EllweinAbstract:PURPOSE. To assess the prevalence of Refractive Error and visual impairment in school-aged African children in South Africa. METHODS. Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age in the Durban area. From January to August 2002, children in 35 clusters were enumerated through a door-to-door survey and examined in temporary facilities. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. In nine clusters, children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance. RESULTS. A total of 5599 children living in 2712 households were enumerated, and 4890(87.3%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye was 1.4%, 1.2%, and 0.32%, respectively. Refractive Error was the cause in 63.6% of the 191 eyes with reduced vision, amblyopia in 7.3%, retinal disorders in 9.9%, corneal opacity in 3.7%, other causes in 3.1%, and unexplained causes in the remaining 12.0%. Exterior and anterior segment abnormalities were observed in 528 (10.8%) children, mainly corneal and conjunctival. Myopia (at least -0.50 D) in one or both eyes was present in 2.9% of children when measured with retinoscopy and in 4.0% measured with autorefraction. Beginning with an upward trend at age 14, myopia prevalence with autorefraction reached 9.6% at age 15. Myopia was also associated with increased parental education. Hyperopia (+2.00 D or more) in at least one eye was present in 1.8% of children when measured with retinoscopy and in 2.6% measured with autorefraction, with no significant predictors of hyperopia risk. CONCLUSIONS. The prevalence of reduced vision is low in school-age African children, most of it because of uncorrected Refractive Error. The high prevalence of corneal and other anterior segment abnormalities is a reflection of the inadequacy of primary eye care services in this area.
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the progression of Refractive Error in school age children shunyi district china
American Journal of Ophthalmology, 2002Co-Authors: Jialiang Zhao, Jin Mao, Rong Luo, Sergio Munoz, Leon B EllweinAbstract:Abstract PURPOSE: To assess the progression of Refractive Error and the incidence of myopia in school-age children in the Shunyi District of Beijing, China. DESIGN: A longitudinal cohort study. METHODS: A population-based sample of 4,662 children initially examined in 1998 at ages 5 to 13 years was reexamined between September and November, 2000. Refractive Error was measured under cycloplegia with autorefraction. Age, sex, and baseline Refractive Error were evaluated as risk factors for progression. RESULTS: In 28.5 months, the average change in Refractive Error was −0.42 diopters (standard deviation, 0.68) in right eyes. Myopic shift of Refractive Error was associated with female sex, older age, and higher myopic or hyperopic Refractive Error at baseline. The average change in astigmatic Error was essentially zero, with significant change in both directions more likely among those with higher baseline astigmatism. Findings were similar for left eyes. The cumulative incidence of myopia, defined as a spherical equivalent Refractive Error of −0.50 diopters or more in either eye, among initial emmetropes and hyperopes was 14.1% (95% confidence interval [CI], 11.8%–16.5%) for male and 23.5% (95% CI, 20.8%–26.1%) for female subjects. Myopia incidence increased sixfold to sevenfold between baseline age 5 and 12, before decreasing at age 13, for both male and female subjects. CONCLUSIONS: In the design of cost-effective programs for the periodic screening and treatment of uncorrected Refractive Error, children initially found to require Refractive correction should be targeted for relatively frequent rescreening, as should girls and older children. Further study is required to better understand environmental and genetic risk factors for myopia development and progression.
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Refractive Error in children in an urban population in new delhi
Investigative Ophthalmology & Visual Science, 2002Co-Authors: G V S Murthy, Gopal P Pokharel, Leon B Ellwein, Sergio Munoz, Sanjeev Kumar Gupta, Lalit Sanga, Damodar BachaniAbstract:PURPOSE: To assess the prevalence of Refractive Error and related visual impairment in school-aged children in an urban population in New Delhi, India. METHODS: Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age. From December 2000 through March 2001, children in 22 selected clusters were enumerated through a door-to-door survey and examined at a local facility. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent Refractive Error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in four of the clusters. RESULTS: A total of 7008 children from 3426 households were enumerated, and 6447 (92.0%) examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 6.4%, 4.9%, and 0.81%, respectively. Refractive Error was the cause in 81.7% of eyes with vision impairment, amblyopia in 4.4%, retinal disorders in 4.7%, other causes in 3.3%, and unexplained causes in the remaining 5.9%. There was an age-related shift in Refractive Error from hyperopia in young children (15.6% in 5-year-olds) toward myopia in older children (10.8% in 15-year-olds). Overall, hyperopia was present in 7.7% of children and myopia in 7.4%. Hyperopia was associated with female gender. Myopia was more common in children of fathers with higher levels of education. CONCLUSIONS: Reduced vision because of uncorrected Refractive Error is a major public health problem in urban school-aged children in India. Cost-effective strategies are needed to eliminate this easily treated cause of vision impairment.
Rakhi Dandona - One of the best experts on this subject based on the ideXlab platform.
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estimation of global visual impairment due to uncorrected Refractive Error
Bulletin of The World Health Organization, 2008Co-Authors: Lalit Dandona, Rakhi DandonaAbstract:The paper by Resnikoff et al.1 on the global magnitude of visual impairment caused by uncorrected Refractive Error published in the Bulletin of the World Health Organization in January 2008 does not refer to our previous publication2 on the same topic in BMC Medicine that precedes their paper by about two years and is readily available in the public domain. The reason for this is unclear as our paper clearly shows up in a PubMed® search for both “blindness” and “visual impairment”. In addition, the global estimates of blindness and visual impairment due to uncorrected Refractive Error made in our paper are know to the blindness community as they were presented at the World Ophthalmology Congress at Sao Paulo in February 2006. It is therefore surprising that Resnikoff et al. did not follow the usual norm of referring to previously published relevant literature. While there are differences in the inclusion criteria for studies in our paper and that of Resnikoff et al., with our paper using stricter criteria leading to fewer qualifying studies, and there were differences in the estimates of blindness and visual impairment due to uncorrected Refractive Error in the two papers, these should not be reasons for not referring to previously published work.
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Refractive Error in children in a rural population in india
Investigative Ophthalmology & Visual Science, 2002Co-Authors: Rakhi Dandona, Lalit Dandona, Gopal P Pokharel, Sergio Munoz, Marmamula Srinivas, Prashant Sahare, Saggam Narsaiah, Leon B EllweinAbstract:PURPOSE. To assess the prevalence of Refractive Error and related visual impairment in school-aged children in the rural population of the Mahabubnagar district in the southern Indian state of Andhra Pradesh. METHODS. Random selection of village-based clusters was used to identify a sample of children 7 to 15 years of age. From April 2000 through February 2001, children in the 25 selected clusters were enumerated in a door-to-door survey and examined at a rural eye center in the district. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent Refractive Error of at least 0.50 D and hyperopia as 2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in seven clusters. RESULTS. A total of 4414 children from 4876 households was enumerated, and 4074 (92.3%) were examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 2.7%, 2.6%, and 0.78%, respectively. Refractive Error was the cause in 61% of eyes with vision impairment, amblyopia in 12%, other causes in 15%, and unexplained causes in the remaining 13%. A gradual shift toward less-positive values of Refractive Error occurred with increasing age in both boys and girls. Myopia in one or both eyes was present in 4.1% of the children. Myopia risk was associated with female gender and having a father with a higher level of schooling. Higher risk of myopia in children of older age was of borderline statistical significance (P 0.069). Hyperopia in at least one eye was present in 0.8% of children, with no significant predictors. CONCLUSIONS. Refractive Error was the main cause of visual impairment in children aged between 7 and 15 years in rural India. There was a benefit of spectacles in 70% of those who had visual acuity of 20/40 or worse in the better eye at baseline examination. Because visual impairment can have a significant impact on a child’s life in terms of education and development, it is important that effective strategies be developed to eliminate this easily treated cause of visual impairment. (Invest Ophthalmol Vis Sci. 2002;43:615‐ 622)
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Refractive Error blindness
Bulletin of the World Health Organization, 2001Co-Authors: Rakhi Dandona, Lalit DandonaAbstract:Recent data suggest that a large number of people are blind in different parts of the world due to high Refractive Error because they are not using appropriate Refractive correction. Refractive Error as a cause of blindness has been recognized only recently with the increasing use of presenting visual acuity for defining blindness. In addition to blindness due to naturally occurring high Refractive Error, inadequate Refractive correction of aphakia after cataract surgery is also a significant cause of blindness in developing countries. Blindness due to Refractive Error in any population suggests that eye care services in general in that population are inadequate since treatment of Refractive Error is perhaps the simplest and most effective form of eye care. Strategies such as vision screening programmes need to be implemented on a large scale to detect individuals suffering from Refractive Error blindness. Sufficient numbers of personnel to perform reasonable quality refraction need to be trained in developing countries. Also adequate infrastructure has to be developed in underserved areas of the world to facilitate the logistics of providing affordable reasonable-quality spectacles to individuals suffering from Refractive Error blindness. Long-term success in reducing Refractive Error blindness worldwide will require attention to these issues within the context of comprehensive approaches to reduce all causes of avoidable blindness.
Kovin Naidoo - One of the best experts on this subject based on the ideXlab platform.
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prevalence of Refractive Error presbyopia and spectacle coverage in bogota colombia a rapid assessment of Refractive Error
Optometry and Vision Science, 2019Co-Authors: Luisa Casas Luque, Thomas Naduvilath, Kovin Naidoo, Ving Fai Chan, Juan Carlos Silva, Fernando Yaacov Pena, Myriam Mayorga, Leonardo RamirezAbstract:SIGNIFICANCEUncorrected Refractive Error is the leading cause of visual impairment; therefore, reducing its prevalence is important worldwide. For two decades, there has not been a comprehensive assessment of Refractive Error in Latin America.PURPOSEThe purpose of this study was to determine the cur
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global vision impairment and blindness due to uncorrected Refractive Error 1990 2010
Optometry and Vision Science, 2016Co-Authors: Kovin Naidoo, Jost B Jonas, Rupert R A Bourne, Konrad Pesudovs, Janet Leasher, Seth Flaxman, Jill E Keeffe, Hans Limburg, Holly Price, Richard A WhiteAbstract:The purpose of this systematic review was to estimate worldwide the number of people with moderate and severe visual impairment (MSVI; presenting visual acuity <6/18, ≥3/60) or blindness (presenting visual acuity <3/60) due to uncorrected Refractive Error (URE), to estimate trends in prevalence from 1990 to 2010, and to analyze regional differences. The review focuses on uncorrected Refractive Error which is now the most common cause of avoidable visual impairment globally. : The systematic review of 14,908 relevant manuscripts from 1990 to 2010 using Medline, Embase, and WHOLIS yielded 243 high-quality, population-based cross-sectional studies which informed a meta-analysis of trends by region. The results showed that in 2010, 6.8 million (95% confidence interval [CI]: 4.7-8.8 million) people were blind (7.9% increase from 1990) and 101.2 million (95% CI: 87.88-125.5 million) vision impaired due to URE (15% increase since 1990), while the global population increased by 30% (1990-2010). The all-age age-standardized prevalence of URE blindness decreased 33% from 0.2% (95% CI: 0.1-0.2%) in 1990 to 0.1% (95% CI: 0.1-0.1%) in 2010, whereas the prevalence of URE MSVI decreased 25% from 2.1% (95% CI: 1.6-2.4%) in 1990 to 1.5% (95% CI: 1.3-1.9%) in 2010. In 2010, URE contributed 20.9% (95% CI: 15.2-25.9%) of all blindness and 52.9% (95% CI: 47.2-57.3%) of all MSVI worldwide. The contribution of URE to all MSVI ranged from 44.2 to 48.1% in all regions except in South Asia which was at 65.4% (95% CI: 62-72%). : We conclude that in 2010, uncorrected Refractive Error continues as the leading cause of vision impairment and the second leading cause of blindness worldwide, affecting a total of 108 million people or 1 in 90 persons.
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prevalence of Refractive Error presbyopia and spectacle coverage in kahama district tanzania a rapid assessment of Refractive Error
Clinical and Experimental Optometry, 2015Co-Authors: Eden Mashayo, Kovin Naidoo, Ving Fai Chan, Prasidh Ramson, Farai ChinanayiAbstract:Background In Tanzania, the prevalence of Refractive Error and presbyopia have not been comprehensively assessed, limiting appropriate planning and implementation of delivery of vision care. This study sought to determine the prevalence of Refractive Error and presbyopia, spectacle coverage and the barriers to uptake of Refractive services in people aged 15 years and older in the Kahama district of Tanzania. Methods A cross-sectional community-based survey was conducted using 54 randomly selected clusters. Respondents 15 years and older were interviewed and underwent standardised clinical eye examinations. Uncorrected Refractive Error (URE) was defined as presenting vision worse than 6/12 that could be corrected to better than 6/12 using a pinhole. Spectacle coverage was defined as the proportion of need that was met (those that improved from unaided vision with their own spectacle correction). Results A total of 3,230 subjects (99.75 per cent of 3,240 eligible) participated in the study with 57.2 per cent males and the median age of participants was 35 years (inter-quartile range, 24 to 49). The prevalence of visual impairment was 10.4 per cent (95% CI 9.4 to 11.4) and was lower in those who had completed their primary school education (odds ratio (OR) 0.54, 95% CI: 0.40 to 0.72) and highest in subjects 40 years and older (OR 3.17, 95% CI: 2.14 to 4.70) and farmers (OR 8.57 95% CI: 2.27 to 32.43). Refractive Error prevalence was 7.5 per cent (95% CI: 6.65 to 8.54) and this was highest in participants over 40 years (OR 1.60, 95% CI: 1.14 to 2.25) and in students (OR 3.64, 95% CI: 1.35 to 9.86). Prevalence of presbyopia was 46.5 per cent (773/1,663, 95% CI: 44.34 to 48.75). Spectacle coverage for Refractive Error and presbyopia was 1.69% (95% CI: 0 to 3.29) and 0.42% (95% CI: 0 to 1.26), respectively. Conclusion Uncorrected Refractive Error is a public health challenge in the Kahama district and sustainable service delivery and health promotion efforts are needed.
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prevalence of Refractive Error and spectacle coverage in zoba ma ekel eritrea a rapid assessment of Refractive Error
Ophthalmic Epidemiology, 2013Co-Authors: Ving Fai Chan, Goitom Mebrahtu, Prasidh Ramson, Mary Wepo, Kovin NaidooAbstract:ABSTRACTPurpose: To determine the prevalence of Refractive Error and spectacle coverage in Zoba Ma’ekel, Eritrea in order to assist in planning for Refractive services and blindness prevention strategies.Methods: A community-based cross-sectional study using multistage cluster sampling was conducted. A total of 3200 participants aged 15–50 years were enumerated and examined using the Rapid Assessment of Refractive Error (RARE) protocol.Results: The response rate was 99.1%. The prevalence of Refractive Error was 6.4% (95% confidence interval [CI], 5.6–7.2%). Spectacle coverage for Refractive Error was 22.2% (95% CI 16.7–28.5%). It was higher among males than females (Fisher’s exact test, p = 0.028), and highest in those who had completed secondary school (48.6%, 95% CI 31.9–65.6%) and those who resided in Asmara (Fisher’s exact test, p < 0.002). The prevalence of presbyopia was 32.9% (95% CI 30.3–35.7%) with 94.9% correctable. Spectacle use for presbyopia was 9.9% (95% CI 7.2–13.4%), which was lowest in th...
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the challenge of uncorrected Refractive Error driving the agenda of the durban declaration on Refractive Error and service development
Clinical and Experimental Optometry, 2010Co-Authors: Kovin Naidoo, Diane Wallace, Brien A Holden, Hasan Minto, Hannah B Faal, Palesa DubeAbstract:The purpose of this article is to highlight the challenge of uncorrected Refractive Error globally, as well as to discuss recent advocacy successes and innovative programs designed to address the need for broader Refractive Error service development, particularly in developing countries. The World Health Organization's VISION 2020: The Right to Sight program first posed the challenge to national governments to give priority to strategies and resources targeted towards avoidable causes of blindness and visual impairment, so that these unnecessary forms of blindness or visual impairment can be eliminated globally by the year 2020. The blindness prevention community is challenged to increase in scale its initiatives, which support the attainment of VISION 2020: The Right to Sight goals primarily and the United Nation's Millennium Development Goals indirectly. The Durban Declaration on Refractive Error and Service Development was the outcome of a meeting of eye-care professionals, researchers, governments, civil society and industry in March 2007 and still stands as a guiding document to the blindness prevention community for the elimination of avoidable blindness due to uncorrected Refractive Error.
Lalit Dandona - One of the best experts on this subject based on the ideXlab platform.
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estimation of global visual impairment due to uncorrected Refractive Error
Bulletin of The World Health Organization, 2008Co-Authors: Lalit Dandona, Rakhi DandonaAbstract:The paper by Resnikoff et al.1 on the global magnitude of visual impairment caused by uncorrected Refractive Error published in the Bulletin of the World Health Organization in January 2008 does not refer to our previous publication2 on the same topic in BMC Medicine that precedes their paper by about two years and is readily available in the public domain. The reason for this is unclear as our paper clearly shows up in a PubMed® search for both “blindness” and “visual impairment”. In addition, the global estimates of blindness and visual impairment due to uncorrected Refractive Error made in our paper are know to the blindness community as they were presented at the World Ophthalmology Congress at Sao Paulo in February 2006. It is therefore surprising that Resnikoff et al. did not follow the usual norm of referring to previously published relevant literature. While there are differences in the inclusion criteria for studies in our paper and that of Resnikoff et al., with our paper using stricter criteria leading to fewer qualifying studies, and there were differences in the estimates of blindness and visual impairment due to uncorrected Refractive Error in the two papers, these should not be reasons for not referring to previously published work.
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Refractive Error in children in a rural population in india
Investigative Ophthalmology & Visual Science, 2002Co-Authors: Rakhi Dandona, Lalit Dandona, Gopal P Pokharel, Sergio Munoz, Marmamula Srinivas, Prashant Sahare, Saggam Narsaiah, Leon B EllweinAbstract:PURPOSE. To assess the prevalence of Refractive Error and related visual impairment in school-aged children in the rural population of the Mahabubnagar district in the southern Indian state of Andhra Pradesh. METHODS. Random selection of village-based clusters was used to identify a sample of children 7 to 15 years of age. From April 2000 through February 2001, children in the 25 selected clusters were enumerated in a door-to-door survey and examined at a rural eye center in the district. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent Refractive Error of at least 0.50 D and hyperopia as 2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in seven clusters. RESULTS. A total of 4414 children from 4876 households was enumerated, and 4074 (92.3%) were examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 2.7%, 2.6%, and 0.78%, respectively. Refractive Error was the cause in 61% of eyes with vision impairment, amblyopia in 12%, other causes in 15%, and unexplained causes in the remaining 13%. A gradual shift toward less-positive values of Refractive Error occurred with increasing age in both boys and girls. Myopia in one or both eyes was present in 4.1% of the children. Myopia risk was associated with female gender and having a father with a higher level of schooling. Higher risk of myopia in children of older age was of borderline statistical significance (P 0.069). Hyperopia in at least one eye was present in 0.8% of children, with no significant predictors. CONCLUSIONS. Refractive Error was the main cause of visual impairment in children aged between 7 and 15 years in rural India. There was a benefit of spectacles in 70% of those who had visual acuity of 20/40 or worse in the better eye at baseline examination. Because visual impairment can have a significant impact on a child’s life in terms of education and development, it is important that effective strategies be developed to eliminate this easily treated cause of visual impairment. (Invest Ophthalmol Vis Sci. 2002;43:615‐ 622)
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Refractive Error blindness
Bulletin of the World Health Organization, 2001Co-Authors: Rakhi Dandona, Lalit DandonaAbstract:Recent data suggest that a large number of people are blind in different parts of the world due to high Refractive Error because they are not using appropriate Refractive correction. Refractive Error as a cause of blindness has been recognized only recently with the increasing use of presenting visual acuity for defining blindness. In addition to blindness due to naturally occurring high Refractive Error, inadequate Refractive correction of aphakia after cataract surgery is also a significant cause of blindness in developing countries. Blindness due to Refractive Error in any population suggests that eye care services in general in that population are inadequate since treatment of Refractive Error is perhaps the simplest and most effective form of eye care. Strategies such as vision screening programmes need to be implemented on a large scale to detect individuals suffering from Refractive Error blindness. Sufficient numbers of personnel to perform reasonable quality refraction need to be trained in developing countries. Also adequate infrastructure has to be developed in underserved areas of the world to facilitate the logistics of providing affordable reasonable-quality spectacles to individuals suffering from Refractive Error blindness. Long-term success in reducing Refractive Error blindness worldwide will require attention to these issues within the context of comprehensive approaches to reduce all causes of avoidable blindness.
Brien A Holden - One of the best experts on this subject based on the ideXlab platform.
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utility and uncorrected Refractive Error
Ophthalmology, 2013Co-Authors: Brien A Holden, Nina Tahhan, Eric B Papas, Timothy R Fricke, Kevin D FrickAbstract:Purpose To investigate utility (a preference-based quality of life [QoL] measure) associated with uncorrected Refractive Error (URE). Design Cross-sectional study. Participants A cohort of 341 consecutive patients 40 to 65 years of age with Refractive Error and no ocular disease impairing vision worse than 20/25 (0.1 logarithm of the minimum angle of resolution [logMAR] units) in the better eye. Without vision correction, 30 had no vision impairment, 65 had only distance vision impairment (DVI), 97 had only near vision impairment (NVI), 112 had moderate amounts of both distance and near vision impairment (DNVI), and 37 had severe impairment (distance or near worse than 20/200 [>1.0 logMAR]) in the better eye. Methods All participants underwent a comprehensive eye examination with refraction, aided and unaided visual acuity (VA) at 6 m and 40 cm, and ocular health assessment. Utilities were elicited for a number of scenarios using a standardized, face-to-face time trade-off (TTO) interview method. Main Outcome Measures The main outcome measure was TTO utility for the participant's own uncorrected vision state. Utilities ranged from 0 to 1, where 0 = death and 1 = perfect vision, and were scaled to account for comorbidities so that 1 = perfect health (adjusted utility). Results Unaided VA was 0.50±0.24 logMAR at distance in the DVI group, 0.43±0.17 logMAR at near in the NVI group, and 0.72±0.36 and 0.56±0.29 at distance and near, respectively, in the DNVI group. Adjusted utilities for the 3 groups were 0.82±0.16 in the DVI group, 0.81±0.17 in the NVI group, and 0.68±0.25 in the DNVI group. The DVI and NVI group utilities (adjusted and unadjusted) did not differ significantly ( P = 0.73 and P = 0.77, respectively). The DNVI utility was significantly worse than that of the DVI and NVI groups (adjusted and unadjusted, P Conclusions The URE is associated with measurable reductions in utility (and therefore QoL). Reductions are similar regardless of whether near or distance vision is impaired, but worse when both are impaired. The results underscore the significance of the effect of URE on QoL, particularly with respect to uncorrected presbyopia, which has been a relatively neglected area in research and policy. The utility figures in this study can be used as inputs for cost-effectiveness studies relating to URE to assist resource allocation decisions. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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the challenge of uncorrected Refractive Error driving the agenda of the durban declaration on Refractive Error and service development
Clinical and Experimental Optometry, 2010Co-Authors: Kovin Naidoo, Diane Wallace, Brien A Holden, Hasan Minto, Hannah B Faal, Palesa DubeAbstract:The purpose of this article is to highlight the challenge of uncorrected Refractive Error globally, as well as to discuss recent advocacy successes and innovative programs designed to address the need for broader Refractive Error service development, particularly in developing countries. The World Health Organization's VISION 2020: The Right to Sight program first posed the challenge to national governments to give priority to strategies and resources targeted towards avoidable causes of blindness and visual impairment, so that these unnecessary forms of blindness or visual impairment can be eliminated globally by the year 2020. The blindness prevention community is challenged to increase in scale its initiatives, which support the attainment of VISION 2020: The Right to Sight goals primarily and the United Nation's Millennium Development Goals indirectly. The Durban Declaration on Refractive Error and Service Development was the outcome of a meeting of eye-care professionals, researchers, governments, civil society and industry in March 2007 and still stands as a guiding document to the blindness prevention community for the elimination of avoidable blindness due to uncorrected Refractive Error.
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potential lost productivity resulting from the global burden of uncorrected Refractive Error
Bulletin of The World Health Organization, 2009Co-Authors: T S T Smith, Timothy R Fricke, Brien A Holden, Kevin D Frick, Kovin NaidooAbstract:OBJECTIVE: To estimate the potential global economic productivity loss associated with the existing burden of visual impairment from uncorrected Refractive Error (URE). METHODS: Conservative assumptions and national population, epidemiological and economic data were used to estimate the purchasing power parity-adjusted gross domestic product (PPP-adjusted GDP) loss for all individuals with impaired vision and blindness, and for individuals with normal sight who provide them with informal care. FINDINGS: An estimated 158.1 million cases of visual impairment resulted from uncorrected or undercorrected Refractive Error in 2007; of these, 8.7 million were blind. We estimated the global economic productivity loss in international dollars (I$) associated with this burden at I$ 427.7 billion before, and I$ 268.8 billion after, adjustment for country-specific labour force participation and employment rates. With the same adjustment, but assuming no economic productivity for individuals aged > 50 years, we estimated the potential productivity loss at I$ 121.4 billion. CONCLUSION: Even under the most conservative assumptions, the total estimated productivity loss, in $I, associated with visual impairment from URE is approximately a thousand times greater than the global number of cases. The cost of scaling up existing Refractive services to meet this burden is unknown, but if each affected individual were to be provided with appropriate eyeglasses for less than I$ 1000, a net economic gain may be attainable.
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Refractive Error and visual impairment in african children in south africa
Investigative Ophthalmology & Visual Science, 2003Co-Authors: Kovin Naidoo, Gopal P Pokharel, Brien A Holden, Avesh Raghunandan, Khathutshelo P Mashige, Pirindhavellie Govender, Leon B EllweinAbstract:PURPOSE. To assess the prevalence of Refractive Error and visual impairment in school-aged African children in South Africa. METHODS. Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age in the Durban area. From January to August 2002, children in 35 clusters were enumerated through a door-to-door survey and examined in temporary facilities. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. In nine clusters, children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance. RESULTS. A total of 5599 children living in 2712 households were enumerated, and 4890(87.3%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye was 1.4%, 1.2%, and 0.32%, respectively. Refractive Error was the cause in 63.6% of the 191 eyes with reduced vision, amblyopia in 7.3%, retinal disorders in 9.9%, corneal opacity in 3.7%, other causes in 3.1%, and unexplained causes in the remaining 12.0%. Exterior and anterior segment abnormalities were observed in 528 (10.8%) children, mainly corneal and conjunctival. Myopia (at least -0.50 D) in one or both eyes was present in 2.9% of children when measured with retinoscopy and in 4.0% measured with autorefraction. Beginning with an upward trend at age 14, myopia prevalence with autorefraction reached 9.6% at age 15. Myopia was also associated with increased parental education. Hyperopia (+2.00 D or more) in at least one eye was present in 1.8% of children when measured with retinoscopy and in 2.6% measured with autorefraction, with no significant predictors of hyperopia risk. CONCLUSIONS. The prevalence of reduced vision is low in school-age African children, most of it because of uncorrected Refractive Error. The high prevalence of corneal and other anterior segment abnormalities is a reflection of the inadequacy of primary eye care services in this area.
