Refractive Error Study in Children: results from La Florida, Chile

PURPOSE: To assess the prevalence of refractive errors and vision impairment in school-age children in a suburban area (La Florida) of Santiago, Chile. METHODS: Random selection of geographically defined clusters was used to identify a representative sample of children 5 to 15 years of age. Children in the 26 selected clusters were enumerated through a door-to-door survey and invited to report to a community health clinic for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and examination of the external eye, anterior segment, media, and fundus were done from April through August 1998. Independent replicate examinations of all children with reduced vision and a sample of those with normal vision were done for quality assurance monitoring in six clusters. RESULTS: A total of 6,998 children from 3,830 households were enumerated, and 5,303 children (75.8%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.50 (20/40) or worse in at least one eye was 15.8%, 14.7%, and 7.4%, respectively; 3.3% had best visual acuity 0.50 or worse in both eyes. Refractive error was the cause in 56.3% of the 1,285 eyes with reduced vision, amblyopia in 6.5%, other causes in 4.3%, with unexplained causes in the remaining 32.9%. Myopia -0.50 diopter or less in either eye was present in 3.4% of 5-year-old children, increasing to 19.4% in males and 14.7% in females by age 15. Over this same age range, hyperopia 2.00 diopters or greater decreased from 22.7% to 7.1% in males and from 26.3% to 8.9% in females. Females had a significantly higher risk of hyperopia than males. CONCLUSIONS: Refractive error, associated primarily with myopia, is a major cause of reduced vision in school-age children in La Florida. More than 7% of children could benefit from the provision of proper spectacles. Efforts are needed to make existing programs that provide free spectacles for school children more effective. Further studies are needed to determine whether the upward trend in myopia continues far beyond 15 years of age.     

Refractive Error Study in Children: results from Mechi Zone, Nepal

PURPOSE: To assess the prevalence of refractive error and vision impairment in school age children in the terai area of the Mechi zone in Eastern Nepal. METHODS: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Children in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and anterior segment, media, and fundus examinations were done from May 1998 through July 1998. Independent replicate examinations for quality assurance monitoring took place in all children with reduced vision and in a sample of those with normal vision in seven villages. RESULTS: A total of 5,526 children from 3,724 households were enumerated, and 5,067 children (91.7%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.5 (20/40) or worse in at least one eye was 2.9%, 2.8%, and 1.4%, respectively; 0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause in 56% of the 200 eyes with reduced uncorrected vision, amblyopia in 9%, other causes in 19%, with unexplained causes in the remaining 16%. Myopia -0.5 diopter or less in either eye or hyperopia 2 diopters or greater was observed in less than 3% of children. Hyperopia risk was associated with female gender and myopia risk with older age. CONCLUSIONS: The prevalence of reduced vision is very low in school-age children in Nepal, most of it because of correctable refractive error. Further studies are needed to determine whether the prevalence of myopia will be higher for more recent birth cohorts.     

The Prevalence of Refractive Errors and Visual Impairment among School Children in Brčko District,Bosnia and Herzegovina

In this study we investigate the prevalence of refractive errors and visual impairment among primary school children in the urban population of Br?ko District, Bosnia and Herzegovina. A cross-sectional study included 40 randomly selected classes of children aged 7–16 years attending five different primary schools in Br?ko District. The examination included visual acuity testing, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, examination of the external eye, anterior segment, media and fundus. A total of 1,005 children were enumerated, and 997 (99.2%) were examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 9.9%, 5.9% and 0.5%, respectively. The prevalence of myopia and hyperopia measured with retinoscopy was 17.3% and 3.0% eyes, and measured with autorefraction 20.4% and 3.3% eyes, respectively. Astigmatism was found in 12.9% eyes with retinoscopy and in 18.1% with autorefraction.     

Refractive error and visual impairment in urban children in southern china

PURPOSE: To assess the prevalence of refractive error and visual impairment in school-age children in a metropolitan area of southern China. METHODS: Random selection of geographically defined clusters was used to identify children 5 to 15 years of age in Guangzhou. Children in 22 clusters were enumerated through a door-to-door survey and examined in 71 schools and 19 community facilities from October 2002 to January 2003. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy, and autorefraction under cycloplegia and examination of the external eye, anterior segment, media, and fundus. RESULTS: A total of 5053 children living in 4814 households were enumerated, and 4364 (86.4%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity 20/40 or worse in the better eye was 22.3%, 10.3%, and 0.62%, respectively. Refractive error was the cause in 94.9% of the 2335 eyes with reduced vision, amblyopia in 1.9%, other causes in 0.4%, and unexplained causes in the remaining 2.8%. External and anterior segment abnormalities were seen in 1496 (34.3%) children, mainly minor conjunctival abnormalities. Media and fundus abnormalities were observed in 32 (0.73%) children. Myopia (spherical equivalent of at least -0.50 D in either eye) measured with retinoscopy affected 73.1% of children 15 years of age, 78.4% with autorefraction. The prevalence of myopia was 3.3% in 5-year-olds with retinoscopy and 5.7% with autorefraction. Females had a significantly higher risk of myopia. Hyperopia (+2.00 D or more) measured with retinoscopy was present in 16.7% of 5-year-olds, 17.0% with autorefraction. The prevalence of hyperopia was below 1% in 15-year-olds, with both methods. Astigmatism (cylinder of > or = 0.75 D) was present in 33.6% of children with retinoscopy and in 42.7% with autorefraction. CONCLUSIONS: The prevalence of reduced vision because of myopia is high in school-age children living in metropolitan Guangzhou, representing an important public health problem. One third of these children do not have the necessary corrective spectacles. Effective strategies are needed to eliminate this easily treated cause of significant visual impairment.     

2010年上海市宝山区小学生屈光不正和视力损伤的患病率调查

背景 流行病学调查表明,青少年视力损伤是一个全球性的公共卫生问题,其首要原因是未矫正的屈光不正,因此一定规模的流行病学调查对儿童屈光不正的矫正具有重要意义.目前尚缺乏上海市大规模儿童视力损伤和屈光不正的流行病学调查资料. 目的 调查上海市6 ～12岁小学生视力损伤与屈光不正的患病情况.方法 采用横断面调查研究设计,于2010年5月至2011年4月分层随机整群抽取上海市宝山区6所学校的4 686名小学生进行研究,眼部检查包括视力、外眼、眼前节、屈光间质、眼底和眼压检查,并记录睫状肌麻痹后电脑验光的结果和眼位.结果 实际受检学生4 594人,应答率为98.0％,接受睫状肌麻痹后验光者3 975人,占84.8％.双眼裸眼视力≤0.5者占14.4％（662/4 594）,其中343人配戴眼镜,占51.8％.所有受检者中,任一眼裸眼视力≤0.5者1 031人,占22.4％.受检的视力损伤者中屈光不正占96.9％（999/1 031）,弱视占3.6％（37/1 031）.接受睫状肌麻痹后验光的小学生中,近视、远视和散光的患病率分别为31.1％、4.3％和33.0％.公办学校的小学生近视患病率高于外来务工随迁子女学校的学生,差异有统计学意义（x2=5.46,P=0.02）.Logistic回归分析显示,年龄和女生与近视的发生及发展明显有关（年龄：OR=1.60,95％ CI：1.53 ～ 1.68,P＜0.01;女生：OR=1.33,95％CI：1.16～1.54,P＜0.01）. 结论 中国上海市小学生视力损害的主要原因是近视,应注意筛查并提高小学生屈光不正的矫正覆盖率.     

The prevalence of refractive errors among schoolchildren in Dezful, Iran

AIM: To determine the prevalence of refractive errors among schoolchildren in urban and rural areas of Dezful County, Iran. METHODS: In a cross-sectional study, using random cluster sampling, 5721 Dezful schoolchildren were selected from 39 clusters. The participants in the study totalled 5544; 3673 elementary and middle school students and 1871 high school students. For the former group, cycloplegic refraction and for the latter, non-cycloplegic refraction was tested. In all participants, uncorrected visual acuity and best corrected visual acuity were determined, and those with a visual acuity of 20/40 or worse, underwent a complete ophthalmic examination to determine the cause of visual impairment. A spherical equivalent of -0.5 diopter (D) or worse was defined as myopia, +2.0 D or more was defined as hyperopia, and a cylinder refraction greater than 0.75 D was considered astigmatism. RESULTS: The uncorrected visual acuity was 20/40 or worse in the better eye of 224 schoolchildren (3.8% of participants). This figure (percentage) was 14 (0.03%) based on their best corrected visual acuity and 96 (1.7%) with their presenting vision. According to results of cycloplegic refraction, 3.4% (95% confidence interval (CI), 2.5 to 4.4) of the primary and middle school students were myopic and 16.6% (95% CI, 13.6 to 19.7) were hyperopic. For high school students, these rates were 2.1% (95% CI, 0.7 to 3.5) and 33.0% (95% CI, 24.9 to 41.1), respectively, with non-cycloplegic refraction. In the multivariate logistic regression for primary and middle school students, myopia was correlated with age (p = 0.030), and hyperopia was correlated with age (p<0.001) and area of residence (p = 0.007). In high school students, hyperopia again showed a correlation with their area of residence (p = 0.029). CONCLUSION: The present study reveals the considerable prevalence rates of refractive errors among schoolchildren in Dezful County and the high rate of an unmet need for their correction. Although myopia is not very prevalent, the high rate of hyperopia in the studied population emphasises its need for attention.     

Refractive error and visual impairment in African children in South Africa

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.     

Prevalence of the refractive errors by age and gender: the Mashhad eye study of Iran

Background: Refractive errors are a common eye problem. Considering the low number of population‐based studies in Iran in this regard, we decided to determine the prevalence rates of myopia and hyperopia in a population in Mashhad, Iran. Design: Cross‐sectional population‐based study. Participants: Random cluster sampling. Of 4453 selected individuals from the urban population of Mashhad, 70.4% participated. Methods: Refractive error was determined using manifest (age >15 years) and cycloplegic refraction (age ≤15 years). Myopia was defined as a spherical equivalent of ?0.5 diopter or worse. An spherical equivalent of +0.5 diopter or worse for non‐cycloplegic refraction and an spherical equivalent of +2 diopter or worse for cycloplegic refraction was used to define hyperopia. Main Outcome Measures: Prevalence of refractive errors. Results: The prevalence of myopia and hyperopia in individuals ≤15 years old was 3.64% (95% CI: 2.19–5.09) and 27.4% (95%CI: 23.72–31.09), respectively. The same measurements for subjects >15 years of age was 22.36% (95%CI: 20.06–24.66) and 34.21% (95%CI: 31.57–36.85), respectively. Myopia was found to increase with age in individuals ≤15 years and decrease with age in individuals >15 years of age. The rate of hyperopia showed a significant increase with age in individuals >15 years. The prevalence of astigmatism was 25.64% (95%CI: 23.76–27.51). Conclusions: In children and the elderly, hyperopia is the most prevalent refractive error. After hyperopia, astigmatism is also of importance in older ages. Age is the most important demographic factor associated with different types of refractive errors.     

Refractive error in children in an urban population in New Delhi

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.     

Prevalence of refractive errors among schoolchildren in Shiraz,Iran

Purpose: To determine the prevalence of refractive errors in Shiraz schoolchildren by age and gender. Methods: For this cross‐sectional study, random cluster sampling was carried out from students of the 2008–2009 academic year. After the initial interview, ophthalmic examinations including tests of visual acuity, non‐cycloplegic and cycloplegic refraction and binocular vision were performed. Myopia was defined as a spherical equivalent ≤?0.50 dioptre (D), hyperopia as ≥+2.0 D, and astigmatism as a cylinder refraction ≥0.75 D. All values for school grade and gender were directly standardized based on the total student population in the 2008–2009 school year. Results: A total of 2130 students were sampled, of which 1872 participated in the study (response rate = 87.88%). The prevalence of uncorrected, best‐corrected, presenting and spectacle corrected visual acuity of 6/12 or worse in the better eye was 6.46%, 0%, 1.49% and 0.9%, respectively. The prevalence rates of myopia, hyperopia and astigmatism were 4.35% (95% confidence interval [CI]: 2.89–5.82%), 5.04% (95% CI: 3.50–6.58%), and 11.27% (95% CI: 9.81–12.74%), respectively. Anisometropia was detected in 2.58% of schoolchildren. The prevalence of hyperopia significantly decreased with age (P = 0.021). Conclusions: Compared with other reported rates, the prevalence of myopia in the schoolchildren of Shiraz is similar to that in most places excluding East Asian countries, and that of hyperopia is in the mid range.