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.     

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.     

Change in vision disorders among Hong Kong preschoolers in 10 years

Background: To determine the change in refractive error and the prevalence of amblyopia and strabismus among preschool children in Hong Kong over a period of 10 years. Design: Two cross‐sectional population‐based studies conducted in 1996 to 1997 (part A) and 2006 to 2007 (part B) Participants: Children attending randomly selected kindergarten participated in the study. Methods: Ocular alignment, visual acuity, cover and uncover tests, cycloplegic refraction, slit‐lamp and fundi examination were performed under a standardized testing environment. Main Outcome Measures: The prevalence of amblyopia (best‐corrected visual acuity ≤6/12 in one or both eyes, or a bilateral difference of ≥2 best‐corrected visual acuity lines), strabismus and significant refractive error (hyperopia ≥+2.50 D; myopia ≥?1.00 D; astigmatism ≥2.00 D) among preschool children. Results: Of the 601 children in part A of the study, reduced visual acuity was presented in 3.8%; whereas strabismus was found in 1.8%. The commonest type of refractive error was astigmatism in 6.3% of children, followed by hyperopia (5.8%) and myopia (2.3%). Among 823 children in part B, reduced visual acuity was presented in 2.7% of children, and strabismus was found in 1.7%. The commonest type of refractive error was myopia (6.3%), followed by astigmatism (5.7%) and hyperopia (5.1%). The percentage of children having myopia has significantly increased (P = 0.001). Conclusion: A significant increase in myopia has been noted in Hong Kong preschoolers. Visual screening programmes may need to be tailored to correspond to the local population and be adjusted accordingly from time to time.     

The age- and gender-specific prevalences of refractive errors in Tehran: the Tehran Eye Study

PURPOSE: To determine the age- and gender-specific prevalences of refractive errors in Tehran through a population-based study. METHODS: A total of 6497 citizens representing a cross-section of the population of Tehran were sampled from 160 clusters using a stratified, random, cluster sampling strategy. Eligible people were enumerated through a door-to-door household survey in the selected clusters and were invited to participate. All participants were transferred to a clinic for an extensive eye examination and interview. Refractive error was determined using manifest and cycloplegic refraction. Myopia was defined as the spherical equivalent of -0.5 diopters (D) or more and hyperopia was defined as the spherical equivalent of more than +0.5 D. RESULTS: Of those sampled, 4565 (70.3%) people participated in the study. Refraction data for 4354 participants aged five years and over are presented. The age- and gender-standardized prevalence of myopia based on manifest refraction was 21.8% (95% confidence interval [CI], 20.1 to 23.5) and that for hyperopia was 26.0% (95% CI, 24.5 to 27.6). The prevalences based on cycloplegic refraction were 17.2% (95% CI, 15.6 to 18.8) and 56.6% (95% CI, 54.7 to 58.6), respectively. Prevalences of myopia and hyperopia differed significantly among the age and gender groups (P < 0.001). Astigmatism of 0.75 cylinder diopter or greater was present in 29.6% (95% CI, 28.0 to 31.3) of right eyes with manifest refraction and in 30.3% (95% CI, 28.5 to 32.1) with cycloplegic refraction. Among the study population, 6.1% (95% CI, 5.3 to 6.8%) had anisometropia of 1 D or more. CONCLUSIONS: This report has provided details of the refractive status in the population. We have documented prevalences of myopia, hyperopia, astigmatism and anisometropia by age and gender, identifying more affected age- and gender-groups for prevention programs in the community.     

The age- and gender-specific prevalences of refractive errors in Tehran: the Tehran Eye Study

purpose?To determine the age- and gender-specific prevalences of refractive errors in Tehran through a population-based study. methods?A total of 6497 citizens representing a cross-section of the population of Tehran were sampled from 160 clusters using a stratified, random, cluster sampling strategy. Eligible people were enumerated through a door-to-door household survey in the selected clusters and were invited to participate. All participants were transferred to a clinic for an extensive eye examination and interview. Refractive error was determined using manifest and cycloplegic refraction. Myopia was defined as the spherical equivalent of ?0.5 diopters (D) or more and hyperopia was defined as the spherical equivalent of more than +0.5?D. results?Of those sampled, 4565 (70.3%) people participated in the study. Refraction data for 4354 participants aged five years and over are presented. The age- and gender-standardized prevalence of myopia based on manifest refraction was 21.8% (95% confidence interval [CI], 20.1 to 23.5) and that for hyperopia was 26.0% (95% CI, 24.5 to 27.6). The prevalences based on cycloplegic refraction were 17.2% (95% CI, 15.6 to 18.8) and 56.6% (95% CI, 54.7 to 58.6), respectively. Prevalences of myopia and hyperopia differed significantly among the age and gender groups (P < 0.001). Astigmatism of 0.75 cylinder diopter or greater was present in 29.6% (95% CI, 28.0 to 31.3) of right eyes with manifest refraction and in 30.3% (95% CI, 28.5 to 32.1) with cycloplegic refraction. Among the study population, 6.1% (95% CI, 5.3 to 6.8%) had anisometropia of 1?D or more. conclusions?This report has provided details of the refractive status in the population. We have documented prevalences of myopia, hyperopia, astigmatism and anisometropia by age and gender, identifying more affected age- and gender-groups for prevention programs in the community.     

Refractive errors in an urban population in Southern India: the Andhra Pradesh Eye Disease Study.

PURPOSE: To assess the prevalence, distribution, and demographic associations of refractive error in an urban population in southern India. METHODS: Two thousand five hundred twenty-two subjects of all ages, representative of the Hyderabad population, were examined in the population-based Andhra Pradesh Eye Disease Study. Objective and subjective refraction was attempted on subjects >15 years of age with presenting distance and/or near visual acuity worse than 20/20 in either eye. Refraction under cycloplegia was attempted on all subjects < or =15 years of age. Spherical equivalent >0.50 D in the worse eye was considered as refractive error. Data on objective refraction under cycloplegia were analyzed for subjects < or =15 years and on subjective refraction were analyzed for subjects >15 years of age. RESULTS: Data on refractive error were available for 2,321 (92.0%) subjects. In subjects < or =15 years of age, age-gender-adjusted prevalence of myopia was 4.44% (95% confidence interval [CI], 2.14%-6.75%), which was higher in those 10 to 15 years of age (odds ratio, 2.75; 95% CI, 1.25-6.02), of hyperopia 59.37% (95% CI, 44.65%-74.09%), and of astigmatism 6.93% (95% CI, 4.90%-8.97%). In subjects >15 years of age, age-gender-adjusted prevalence of myopia was 19.39% (95% CI, 16.54%-22.24%), of hyperopia 9.83% (95% CI, 6.21%-13.45%), and of astigmatism 12.94% (95% CI, 10.80%-15.07%). With multivariate analysis, myopia was significantly higher in subjects with Lens Opacity Classification System HI nuclear cataract grade > or =3.5 (odds ratio, 9.10; 95% CI, 5.15-16.09), and in subjects with education of class 11 or higher (odds ratio, 1.80; 95% CI, 1.18-2.74); hyperopia was significantly higher in subjects > or =30 years of age compared with those 16 to 29 years of age (odds ratio, 37.26; 95% CI, 11.84-117.19), in females (odds ratio, 1.86; 95% CI, 1.33-2.61), and in subjects belonging to middle and upper socioeconomic strata (odds ratio, 2.10; 95% CI, 1.09-4.03); and astigmatism was significantly higher in subjects > or =40 years of age (odds ratio, 3.00; 95% CI, 2.23- 4.03) and in those with education of college level or higher (odds ratio, 1.73; 95% CI, 1.07-2.81). CONCLUSIONS: These population-based data on distribution and demographic associations of refractive error could enable planning of eye-care services to reduce visual impairment caused by refractive error. If these data are extrapolated to the 255 million urban population of India, among those >15 years of age an estimated 30 million people would have myopia, 15.2 million hyperopia, and 4.1 million astigmatism not concurrent with myopia or hyperopia; in addition, based on refraction under cycloplegia, 4.4 million children would have myopia and 2.5 million astigmatism not concurrent with myopia or hyperopia.     

Refractive errors in students from Middle Eastern backgrounds living and undertaking schooling in Australia

Background: Environmental factors associated with schooling systems in various countries have been implicated in the rising prevalence of myopia, making the comparison of prevalence of refractive errors in migrant populations of interest. This study aims to determine the prevalence of refractive errors in children of Middle Eastern descent, raised and living in urban Australia but actively maintaining strong ties to their ethnic culture, and to compare them with those in the Middle East where myopia prevalence is generally low. Methods: A total of 354 out of a possible 384 late primary/early secondary schoolchildren attending a private school attracting children of Middle Eastern background in Melbourne were assessed for refractive error and visual acuity. A Shin Nippon open‐field NVision‐K5001 autorefractor was used to carry out non‐cycloplegic autorefraction while viewing a distant target. For statistical analyses students were divided into three age groups: 10–11 years (n = 93); 12–13 years (n = 158); and 14–15 years (n = 102). Results: All children were bilingual and classified as of Middle Eastern (96.3 per cent) or Egyptian (3.7 per cent) origin. Ages ranged from 10 to 15 years, with a mean of 13.17 ± 0.8 (SEM) years. Mean spherical equivalent refraction (SER) for the right eye was +0.09 ± 0.07 D (SEM) with a range from ‐7.77 D to +5.85 D. The prevalence of myopia, defined as a spherical equivalent refraction 0.50 D or more of myopia, was 14.7 per cent. The prevalence of hyperopia, defined as a spherical equivalent refraction of +0.75 D or greater, was 16.4 per cent, while hyperopia of +1.50 D or greater was 5.4 per cent. A significant difference in SER was seen as a function of age; however, no significant gender difference was seen. Conclusions: This is the first study to report the prevalence of refractive errors for second‐generation Australian schoolchildren coming from a predominantly Lebanese Middle Eastern Arabic background, who endeavour to maintain their ethnic ties. The relatively low prevalence of myopia is similar to that found for other metropolitan Australian school children but higher than that reported in the Middle East. These results suggest that lifestyle and educational practices may be a significant influence in the progression of myopic refractive errors.     

Epidemiologic study of refractive errors in schoolchildren in socioeconomically deprived regions in Tunisia

PURPOSE: This study's purpose was to estimate the prevalence of common refractive errors in schoolchildren in low socioeconomic regions in Tunisia and to assess their effect on school performance. MATERIAL AND METHODS: This was a cross-sectional study done from November 1999 to January 2000 within the context of health care screening campaigns carried out by volunteer ophthalmologists and opticians in low-end socioeconomic regions in Tunisia. The concerned population was schoolchildren living in the cities of Tunis and Tabarka (North), Kerkena (Center), and Tozeur (South). We examined a total of 708 children with a mean age of 11.9 +/-3.21 years (from 6 to 20 years) and a sex ratio of 0.84. A cycloplegic refraction examination was performed on all the children. Statistical analyses with the chi squared test and the Fisher exact test allowed us to calculate the prevalence of the refractive errors totally and separately as well as the distribution according to age, sex, and region. We also searched for a possible relation between refractive errors and academic failure. RESULTS: Among the 708 children, 57.2% [CI(95)=53.4-60] had refractive errors, of which 31.6% [CI(95)=28.2-35.2] were hyperopic, whereas 9.1% [CI(95)=7.1-11.5] were myopic. Astigmatism was found in 16.4% [CI(95)=13.7-19.3]. The prevalence of myopia was significantly higher after the age of fourteen. It increased significantly with age (P=0.0003). The prevalence of hyperopia was significantly higher between the ages of 8 and 11 (P=0.0004). Hyperopic astigmatism was significantly more frequent between 6 and 9 years of age (P=0.001). There was no significant difference regarding sex. However, the distribution of the refractive errors by region showed a significantly high level of myopia in Tunis, Kerkena, and Tozeur. This difference disappeared with increasing age. The study of the effect of these refractive errors on school performance of these children from poor areas showed a significant association between all types of refractive errors and academic failure, with an odds ratio of 2.13 for all types of refractive errors, 2.69 for hyperopia, 2.87 for myopia, and 2.73 for astigmatism. CONCLUSION: This study showed the prevalence of refractive errors in a poor population of schoolchildren and emphasized the importance of such examinations. The ability of a child to participate in the educational experience is at least partially dependent on good vision.     

The Prevalence of Anisometropia,Amblyopia and Strabismus in Schoolchildren of Shiraz,Iran

Purpose: To determine the prevalence of amblyopia, anisometropia, and strabismus in schoolchildren of Shiraz, Iran.

Materials and Methods: A random cluster sampling was used in a cross-sectional study on schoolchildren in Shiraz. Cycloplegic refraction was performed in elementary and middle school children and high school students had non-cylcoplegic refraction. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded for each participant. Anisometropia was defined as spherical equivalent (SE) refraction difference 1.00D or more between two eyes. Amblyopia was distinguished as a reduction of BCVA to 20/30 or less in one eye or 2-line interocular optotype acuity differences in the absence of pathological causes. Cover test was performed for investigating of strabismus.

Results: Mean age of 2638 schoolchildren was 12.5 years (response rate?=?86.06%). Prevalence of anisometropia was 2.31% (95% confidence interval [CI], 1.45 to 3.16). 2.29% of schoolchildren (95% CI, 1.46 to 3.14) were amblyopic. The prevalence of amblyopia in boys and girls was 2.32% and 2.26%, respectively (p?=?0.945). Anisometropic amblyopia was found in 58.1% of the amblyopic subjects. The strabismus prevalence was 2.02% (95% CI, 1.18 to 2.85). The prevalence of exotropia and esotropia was 1.30% and 0.59%, respectively.

Conclusions: Results of this study showed that the prevalence of anisometropia, amblyopia, and strabismus are in the mid range. The etiology of amblyopia was often refractive, mostly astigmatic, and non-strabismic. Exotropia prevalence increased with age and was the most common strabismus type.     

山东省冠县4～18岁学生屈光不正横断面研究

目的 调查山东省冠县4～18岁在校（园）学生屈光不正患病状况.方法 横断面调查研究.通过随机整群抽样从冠县幼儿园、小学、初中和高中随机抽取学生进行屈光不正现况调查.所有学生接受裸眼视力、矫正视力、散瞳验光、眼内压、眼前节、眼后节等检查.屈光不正与性别、年龄的关系采用二元Logistic回归模型进行分析.结果 共3 112例4～18岁在校（园）学生接受检查,其中完成散瞳验光检查3 111例,完成视力检查3 094例.近视患病率为31.3％ （95％CI：29.7％～33.0％）,年龄较大[OR：1.49 （95％CI：1.45～1.54）,P＜0.01]、女性[OR：1.31 （95％CI：1.09～1.57）,P＜0.01]和城镇学生[OR：2.54（95％CI：2.11～3.07）,P＜0.01]的近视患病率较高.高度近视总体患病率为1.4％ （95％CI：1.0％～1.8％）,散光的总体患病率为32.4％（95％CI：30.8％～34.0％）,屈光参差的总体患病率为6.2％（95％CI：5.4％～7.1％）,高度近视、散光和屈光参差患病率均呈现随年龄增长而上升的趋势（P＜0.01）,其中散光和屈光参差的患病率与居住地有关（P＜0.01）,但均与性别无关（P＞0.05）;远视患病率为8.2％（95％CI：7.2％～9.2％）,并随年龄增加而下降[OR：0.72（95％CI：0.68～0.76）;P＜0.01].较好眼裸眼视力≤20/40和≤20/200者分别有675例（21.8％）和85例（2.7％）.单眼或双眼裸眼视力≤20/40的880人中,837人（95.1％）是由于屈光不正导致的.结论 山东省冠县4～18岁在校（园）学生的视力损害主要由以近视为主的屈光不正导致,且呈现出随随年龄增加而上升的趋势.     

复方托吡卡胺和阿托品在儿童验光检查中的应用研究

目的探讨复方托吡卡胺滴眼液和阿托品眼用凝胶在儿童验光检查中的应用效果及其相关性。 方法收集2016年1月至2019年3月于首都医科大学附属北京同仁医院眼科中心就诊儿童151例(302只眼)的资料。其中,男性68例(136只眼),女性83例(166只眼);年龄3~10岁,平均年龄(6.0±1.5)岁。根据屈光状态将患儿分为远视眼组、混合散光组及近视眼组。各组患儿均先后进行复方托吡卡胺和阿托品散瞳,而后检查并记录患儿的球镜值、柱镜值、轴向值及最佳矫正视力。所有指标经Kolmogorov-Smirnov正态性检验,不符合正态分布时,以中位数和四分位数描述。组内比较采用配对样本秩和检验。不同年龄患儿两种药物散瞳验光结果中球镜差值的比较,采用独立样本秩和检验。患儿两种药物散瞳验光结果中球镜值间的关系,采用一元线性回归进行分析。 结果远视眼组、混合散光组及近视眼组患儿分别有63例(126只眼)、41例(82只眼)和47例(94只眼)。三组患儿性别间的比较,差异无统计学意义(χ²＝0.171,P>0.05);三组患儿年龄间的比较,差异无统计学意义(F＝1.399,P>0.05)。远视眼组患儿复方托吡卡胺散瞳验光结果中的球镜值、柱镜值、轴向值及最佳矫正视力分别为2.50(1.00,5.31)D、1.00(0.50,1.75)D、90(85,100)°及0.10(0.00,0.20);阿托品散瞳验光结果中的球镜值、柱镜值、轴向值及矫正视力分别为3.50(2.00,6.31)D、1.00(0.50,1.75)D、90(85,95)°及0.10(0.00,0.20)。经配对样本秩和检验,各组患儿球镜值、柱镜值及最佳矫正视力的比较,差异有统计学意义(Z＝9.692,-2.726,-2.483;P<0.05);但轴向值的比较,差异无统计学意义(Z＝-0.173,P>0.05)。混合散光组患儿复方托吡卡胺散瞳验光结果中的球镜值、柱镜值、轴向值及最佳矫正视力分别为-1.00(-2.00,-0.75)D、3.00(2.00,4.00)D、90(85,95)°及0.10(0.00,0.20);阿托品散瞳验光结果中的球镜值、柱镜值、轴向值及最佳矫正视力分别为-0.50(-1.25,0.00)D、3.00(2.00,4.00)D、90(85,95)°及0.10(0.00,0.20)。经配对样本秩和检验,各组患儿球镜值和最佳矫正视力的比较,差异有统计学意义(Z＝7.778,-2.826;P<0.05);但柱镜值和轴向值的比较,差异无统计学意义(Z＝-1.098 ,-0.653;P>0.05)。近视眼组患儿复方托吡卡胺散瞳验光结果中的球镜值、柱镜值、轴向值及最佳矫正视力分别为-3.50(-6.00,-1.25)D、-1.38(-2.50,-0.50)D、90(85,95)°及0.00(0.00,0.20);阿托品散瞳验光结果中的球镜值、柱镜值、轴向值及最佳矫正视力分别为-3.13(-5.25,-1.00)D、-1.50(-2.50,-0.50)D、90(85,95)°及0.10(0.00,0.20)。经配对样本秩和检验,各组患儿球镜值和最佳矫正视力的比较,差异有统计学意义(Z＝8.388,-2.744;P<0.05);但柱镜值和轴向值的比较,差异无统计学意义(Z＝0.511,-1.735;P>0.05)。远视眼组、混合散光组及近视眼组患儿两种药物散瞳验光结果中的球镜值函数关系分别为y_阿托品＝1.068+0.976x_{复方托吡卡胺}、y_阿托品＝0.775+0.999x_{复方托吡卡胺}及y_阿托品＝0.248+0.949x_{复方托吡卡胺}。远视眼组、混合散光组及近视眼组<6岁患儿的球镜差值分别为1.00(0.75,1.44)D、1.00(0.50,1.25)D及0.50(0.25,0.75)D;≥6岁患儿的球镜差值分别为0.75(0.50,1.00)D、0.50(0.25,0.75)D及0.25(0.00,0.50)D;经独立样本秩和检验,组内两者的比较差异有统计学意义(Z＝-2.261,-4.160,-2.360;P<0.05)。 结论各组两种药物散瞳后,年龄越小者验光结果差异越大。远视眼和混合散光患儿应采用阿托品散瞳验光,在特殊情况下对混合散光和年龄≤6岁的近视眼患儿可在复方托吡卡胺散瞳验光结果的基础上,再根据两者的函数关系修正为阿托品的验光结果,6岁以上近视眼患儿建议采用复方托品卡胺散瞳验光。     

Prevalence and risk factors for refractive errors in adult Chinese in Singapore

PURPOSE: To determine the epidemiology of refractive errors in an adult Chinese population in Singapore. METHODS: A disproportionate, stratified, clustered, random-sampling procedure was used to select names of 2000 Chinese people aged 40 to 79 years from the 1996 Singapore electoral register in the Tanjong Pagar district in Singapore. These people were invited to a centralized clinic for a comprehensive eye examination, including refraction. Refraction was also performed on nonrespondents in their homes. Myopia, high myopia, and hyperopia were defined as a spherical equivalent (SE) in the right eye of less than -0.5 D, less than -5.0 D, and more than +0.5 D, respectively. Astigmatism was defined as less than -0.5 D of cylinder. Anisometropia was defined as a difference in SE of more than 1.0 D between the two eyes. Only phakic eyes were analyzed. RESULTS: From 1717 eligible people, 1232 (71.8%) were examined. Adjusted to the 1997 Singapore population, the overall prevalence of myopia, hyperopia, astigmatism, and anisometropia was 38.7% (95% confidence interval [CI]: 35.5, 42.1), 28.4% (95% CI: 25.3, 31.3), 37.8% (95% CI: 34.6, 41.1), and 15.9% (95% CI: 13.5, 18.4), respectively. The prevalence of high myopia was 9.1% (95% CI: 7.2, 11.2), with women having significantly higher rates than men. The age pattern of myopia was bimodal, with higher prevalence in the 40 to 49 and 70 to 81 age groups and lower prevalence between those age ranges. Prevalence was reversed in hyperopia, with a higher prevalence in subjects aged 50 to 69. There was a monotonic increase in prevalence with age for both astigmatism and anisometropia. Increasing educational levels, higher individual income, professional or office-related occupations, better housing, and greater severity of nuclear opacity were all significantly associated with higher rates of myopia, after adjustment for age and sex. CONCLUSIONS: The results indicate that whereas myopia is 1.5 to 2.5 times more prevalent in adult Chinese residing in Singapore than in similarly aged European-derived populations in the United States and Australia, the sociodemographic associations are similar.     

Prevalence rates of refractive errors in Sumatra,Indonesia

PURPOSE: To determine the prevalence rates of myopia, hyperopia, astigmatism, and anisometropia in a prevalence survey of adults in Sumatra, Indonesia. METHODS: A population-based prevalence survey of 1043 adults 21 or more years of age was conducted in five rural villages and one provincial town of the Riau Province, Sumatra, Indonesia. A one-stage household cluster sampling procedure was used wherein 100 households were selected from each village or town. Refractive error measurements were obtained with one of two handheld autorefractors. Household interviews were conducted to obtain information on relevant lifestyle risk factors. RESULTS: The age-adjusted overall prevalence rates of myopia (SE [spherical equivalent] at least -1.0 D), hyperopia (SE of at least +1.0 D), astigmatism (cylinder of at least -1.0 D), and anisometropia (SE difference of +1.0 D) were 26.1% (95% confidence interval [CI]: 23.4-28.8), 9.2% (95% CI: 7.4-11.0), 18.5% (95% CI: 16.2-20.8), and 15.1% (95% CI: 12.9-17.4), respectively. The age-adjusted overall prevalence rate of high myopia (SE at least -6.0 D) was 0.8% (95% CI: 0.2-1.5). In a multiple logistic regression model, myopia rates varied with age and increased with income. Hyperopia, astigmatism, and anisometropia rates were independently higher in older adults. CONCLUSIONS: The prevalence rates of myopia in provincial Sumatra are higher than the rates in white populations, but lower than the rates in other urbanized Asian countries such as Singapore. The prevalence rate of high myopia is lower than in most other populations, and other refractive errors are common.     

A longitudinal study of cycloplegic refraction in a cohort of 350 Japanese schoolchildren. Cycloplegic refraction

We performed a 5 year longitudinal study of cycloplegic refraction in a cohort of 350 Japanese schoolchildren from 6 to 11 years of age in a rural area of southwestern Japan. The spherical refraction was measured under cycloplegia with an infrared autorefractometer. The grouped data from 350 right eyes showed leptokurtic frequency distributions, and the median was +0.91 D at age 6 yrs, shifted towards emmetropia with increasing age and reached +0.34 D at age 11 years. The prevalence of myopia of -1.0 D or more was 0.3%, 0.6%, 2.0%, 2.6%, 2.9%, and 4.9% from age 6 to 11 years, and the prevalence of myopia of more than -2.0 D was less than 1% at age 6-9 years and thereafter increased up to 6.0% at age 11 years. Linear regression analysis for the longitudinal refractive data revealed that 247 (70.6%) of the 350 eyes exhibited first-order linear decrease in hyperopia or increase in myopia with an average annual change of -0.15 D/year, 14 (4%) showed second-order curvilinear change, and 89 (25.4%) remained unchanged. In the eyes with linear change, there was a significant relationship between the refraction at age 6 years and the rate of subsequent change such that the less hyperopic or emmetropic at age 6 years, the larger the change. The refraction at birth was estimated by extrapolation of the linear regression analysis results, implying that 88% of newborns have hyperopia of +1.0 D or greater and myopia is rare. These results indicate the current state of refraction in Japanese schoolchildren of a rural area.     

Strabismus,refractive errors and nystagmus in children and young adults with Down syndrome

Purpose: The aims of the present population-based, cross-sectional study were to examine the frequency and type of strabismus, refractive errors and nystagmus in children and young adults with Down syndrome (DS) in Macedonia and Croatia.

Methods: A total of 170 unselected children and young adults with DS aged 1–34 years were examined for ocular findings. The ocular examination included: a visual acuity assessment, cycloplegic refraction, ocular alignment and ocular motility.

Results: Strabismus was found in 45 of 170 children (26.5%), and esodeviation was the most common type. Nine (20%) had exodeviation and 4 (8.9%) vertical deviation. In 27 of 32 esotropic patients, the strabismus was regarded as acquired esodeviations. The frequency of strabismus was lowest in the high-grade hyperopia group (5%). Concerning esodeviations, fewer cases (3%) were in the high-grade hyperopia group. Most of the cases with esodeviations were in correlation with low-grade hyperopia (31%), myopia (28 %) and emetropia (16%). Hyperopia was the most common refractive error and high myopia increased in prevalence in the over 20 age group. Astigmatism was present in 72.4% of patients. Nystagmus was observed in 18 patients. Ten of 18 patients with nystagmus were associated with the presence of strabismus (9 esodeviations, 1 exotropia).

Conclusion: In our study, the high prevalence of strabismus can not be attributed to the presence of hyperopia. Our data show no association between refraction and strabismus in children with DS. Oblique astigmatism has been found to be the most common type of astigmatism in our study group.     

Correctable and non-correctable visual impairment in a population-based sample of 12-year-old Australian children

PURPOSE: To document the prevalence of correctable and non-correctable visual impairment in a representative sample of Australian children, predominantly age 12 years. DESIGN: Population-based cross-sectional study. METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes unaided, with spectacles if worn, and after subjective refraction if required, in 2353 children, examined during 2004 to 2005. Cycloplegic autorefraction (using cyclopentolate) and dilated fundus examination were performed. Using a cut-off of 0.3 logMAR units (<20/40), presenting visual impairment was defined using unaided visual acuity if spectacles were not worn or with usual correction if spectacles were worn. Impairment not eliminated by refraction was considered non-correctable; any difference between this and presenting impairment was defined as correctable impairment. Myopia was defined as spherical equivalent refraction (SER) < or =-0.50 diopters (D), hyperopia as SER > or =+2.0 diopters, anisometropia as SER difference > or =1.00 diopters, and astigmatism as cylinder > or =1.0 diopters. Amblyopia was defined as corrected visual acuity <0.3 logMAR not attributable to an underlying structural eye or visual pathway abnormality. RESULTS: Visual impairment was found in the worse eye of 117 children (5.0%) and comprised correctable (82%) and non-correctable impairment (18%). Correctable impairment was due to myopia in 67 (69.8%), hyperopia in 11 (11.5%) and astigmatism in 32 subjects (33.3%). Causes of non-correctable impairment were: amblyopia 66.7%, congenital glaucoma 9.5%, optic nerve hypoplasia 9.5%, congenital nystagmus 4.8%, and cortical blindness 4.8%. CONCLUSIONS: Visual impairment had a relatively low prevalence in this older childhood population, a large proportion of which was correctable by refraction alone.     

Laser in situ keratomileusis for myopia and hyperopia using the Lasersight 200 laser in 300 consecutive eyes

PURPOSE: To evaluate effectiveness, safety, predictability, and short-term stability of laser in situ keratomileusis (LASIK) using the LaserSight Compac-200 Mini excimer laser with software version 9.0, for all refractive errors. METHODS: One hundred fifty consecutive patients (300 eyes) that received bilateral LASIK for myopia, hyperopia, and astigmatism were studied prospectively. A new 9.0 software version applying a modified nomogram that takes advantage of bilateral surgery was used. Follow-up at 6 months was available for 267 eyes (89%). RESULTS: Six months postoperatively, 131 eyes (96.32%) in the low to moderate myopia group (-1.00 to -5.99 D; n=136) had a spherical equivalent refraction within +/-1.00 D, and 123 eyes (90.44%) were within +/-0.50 D of emmetropia. In the high to extreme myopia group (-6.00 to -25.00 D; n=114), 97 eyes (87.08%) had a spherical equivalent refraction within +/-1.00 D and 78 eyes (68.42%) were within +/-0.50 D of emmetropia. In the hyperopia group (+1.00 to +6.00 D; n=50), 44 eyes (88%) had a postoperative spherical equivalent refraction within +/-1.00 D, and 31 eyes (62%) were within +/-0.50 D of emmetropia. Mean change in spherical equivalent refraction at 6 months was less than -0.50 D in the low to high myopia groups and -1.16 +/- 0.55 D in the extreme myopia group. At 6 months follow-up, uncorrected visual acuity was 20/20 or better in 73 eyes (54%) in the low to moderate myopia groups and 21 eyes (18%) in the high to extreme myopia groups. In the hyperopia group at 6 months follow-up, uncorrected visual acuity was 20/20 or better in 31 eyes (62%) and 20/40 or better in 41 eyes (82%). Only two eyes had a temporary loss of two or more lines of spectacle-corrected visual acuity due to corneal folds that were surgically treated. Six months after LASIK, no eye had lost any lines of best spectacle-corrected visual acuity in this series. CONCLUSIONS: Our modified LASIK nomogram with the 9.0 software of the LaserSight 200 excimer laser (with a larger and smoother ablation pattern) resulted in safe and effective outcomes for the treatment of low to high myopia, astigmatism, and hyperopia.     

Refractive errors in an elderly Chinese population in Taiwan: the Shihpai Eye Study

PURPOSE: Few epidemiologic data are available on refractive status in elderly Asians. The purpose of the study was to determine prevalence and risk factors associated with refractive errors in a metropolitan elderly Chinese population in Taiwan. METHODS: A population-based survey was conducted in the Shihpai district of Taipei, Taiwan. A total of 2045 residents aged 65 years or more were randomly selected and invited to complete a comprehensive questionnaire and undertake a detailed ocular examination, including best corrected visual acuity and measurements of refractive error, using autorefraction. Of the subjects, 1361 (66.6%) participated in the ocular examination. Spherical equivalent (SE) was calculated in diopters (D), and data from right eyes were reported. RESULTS: The age- and sex-adjusted prevalence rates were determined for myopia (SE<-0.5 D, 19.4%; SE<-1.0 D, 14.5%), high myopia (SE<-6.0 D, 2.4%), hyperopia (SE>+0.5 D, 59.0%; SE>+1.0 D, 44.2%), astigmatism (cylinder<-0.5 D, 74.0%; cylinder<-1.0 D, 45.3%), and anisometropia (SE difference between right and left eyes>0.5 D, 45.2%; SE difference>1.0 D, 21.8%). The prevalence of myopia, astigmatism, and anisometropia significantly increased with age (all P<0.01). The prevalence of hyperopia tended to decrease with age. There was no gender difference in prevalence rates in any type of refractive error, except that women had a higher rate of hyperopia (SE>+1.0 D) than men (P=0.004). Multivariate regression analysis showed that myopia was weakly associated with higher educational level. The severity of lens nuclear opacity was positively associated with the rates of myopia and negatively associated with the rates of hyperopia. CONCLUSIONS: The prevalence of myopia in this elderly Chinese population is not much higher than in similarly aged elderly white populations, compared with a much greater difference in prevalence among younger Chinese versus white people. This suggests that changing environmental factors may account for the increased prevalence of myopia in younger cohorts of Chinese.     

Population-based assessment of refractive error in India: the Andhra Pradesh eye disease study

Purpose: To assess the prevalence, distribution, and demographic associations of refractive error in the population of the southern Indian state of Andhra Pradesh. Methods: From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 persons of all ages were sampled using a stratified, random, cluster, systematic sampling strategy in the Andhra Pradesh Eye Disease Study, a population‐based cross‐sectional study. A total of 10 293 people underwent an interview and detailed dilated eye examination. Refraction was performed by ophthalmic personnel trained in the study procedures. Objective refraction under cycloplegia was assessed for participants ≤ 15 years of age and subjective refraction for those > 15 years of age. Myopia was defined as spherical equivalent worse than ‐0.50 D and hyperopia as spherical equivalent worse than +0.50 D. Results: In the participants ≤ 15 years of age, the prevalence of myopia was 3.19% (95% confidence interval [CI] 2.24?4.13%) and of hyperopia was 62.62% (95% CI 57.10?68.13%). In this age group, myopia increased with increasing age and was more prevalent in the urban study area, and hyperopia prevalence was greater in the participants < 10 years of age. In participants > 15 years of age, the prevalence of myopia was 19.45% (95% CI 17.88?21.02%) and of hyperopia was 8.38% (95% CI 6.91?9.85%). Myopia and hyperopia increased with increasing age. Myopia was more common in males, those with education higher than class 12, those with nuclear cataract, and those living in rural study areas. Hyperopia was more common in females, those with any level of formal education, and those living in the urban area and in the well‐off rural study area. Conclusions: There is significant refractive error in this population. These data on the distribution and associations of refractive error can be useful for the planning of refractive eye‐care services.