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.     

重庆酉阳县土家族青少年屈光不正及相关因素的流行病学调查

目的：了解重庆市酉阳县土家族青少年人群屈光不正的患病率及其影响因素。方法：横断面调查研究。采用分层整群抽样的方法,对重庆市酉阳县城镇和乡村各2所中学（初中和高中）的土家族青少年共973例进行眼科检查。通过电脑自动验光及1%环戊通滴眼液扩瞳后检影验光获得青少年的屈光状态,以调查问卷方式了解并分析近视发生的相关因素,包括户外活动时间、父母屈光状态等。采用Pearson卡方检验以及Pearson和Spearman相关性分析对数据进行处理。结果：近视（等效球镜度≤-0.50 D）、远视（等效球镜度≥+0.50 D）以及散光（柱镜度≤-0.50 D）的患病率分别为66.3%（645例）,17.5%（170例）和15.1%（147例）。高度近视检出25例,占总检出人数的2.6%。男生近视患病率（59.8%）显著低于女生（72.5%） （ χ 2 =17.53,P < 0.001）。城镇青少年近视患病率（77.9%）显著高于乡村青少年（51.6%） （ χ 2 =74.12,P < 0.001）。随着年龄增长,近视患病率逐渐升高（ χ 2 =84.70,P < 0.001）,远视患病率逐渐降低（ χ 2 =78.30,P < 0.001）。近视的土家族青少年中,父母双方均存在（ χ 2 =10.85,P=0.001）或单方存在（ χ 2 =56.01,P < 0.001）近视的概率显著高于非近视青少年。青少年户外活动时间与屈光状态呈显著正相关（r 2 =0.781,P < 0.001）。结论：重庆市酉阳县土家族青少年女性近视患病率较高;城镇青少年近视患病率高于乡村;近视发病与父母近视和户外活动时间相关。     

Utility values and myopia in teenage school students

AIM: To ascertain the utility values of myopic teenage students in Singapore. METHODS: Children (n=699) aged 15-18 years with myopia (spherical equivalent (SE) at least -0.5 dioptres (D)) in two high schools in Singapore were recruited. Information on time trade-off (years of life willing to sacrifice for treatment of myopia) and standard gamble for blindness (risk of blindness from therapy willing to sacrifice for treatment of myopia) utility values, demographic, and socioeconomic status data were obtained. RESULTS: The time trade-off and standard gamble for blindness utility values were 0.93 (95% confidence interval (CI) 0.93 to 0.94) and 0.85 (95% CI 0.84 to 0.86), respectively. Children with presenting better eye logMAR visual acuity >0.3 had lower time trade-off utility values (mean 0.92 versus mean 0.94), after adjusting for race and sex. There were dose-response relations between standard gamble for blindness values and total family income, as well as both utility values and educational stream (all p values for trend <0.01), after controlling for the same factors. CONCLUSION: The utility values in myopic students were higher for teenagers with better presenting visual acuity, children who wore spectacles or contact lenses, higher total family income, more "academic" schooling stream, and who were non-Muslims.     

Refractive Errors in Koreans: The Korea National Health and Nutrition Examination Survey 2008-2012

PurposeOur study provides epidemiologic data on the prevalence of refractive errors in all age group ≥5 years in Korea.MethodsIn 2008 to 2012, a total of 33,355 participants aged ≥5 years underwent ophthalmologic examinations. Using the right eye, myopia was defined as a spherical equivalent (SE) less than -0.5 or -1.0 diopters (D) in subjects aged 19 years and older or as an SE less than -0.75 or -1.25 D in subjects aged 5 to 18 years according to non-cycloplegic refraction. Other refractive errors were defined as follows: high myopia as an SE less than -6.0 D; hyperopia as an SE larger than +0.5 D; and astigmatism as a cylindrical error less than -1.0 D. The prevalence and risk factors of myopia were evaluated.ResultsPrevalence rates with a 95% confidence interval were determined for myopia (SE <-0.5 D, 51.9% [51.2 to 52.7]; SE <-1.0 D, 39.6% [38.8 to 40.3]), high myopia (5.0% [4.7 to 5.3]), hyperopia (13.4% [12.9 to 13.9]), and astigmatism (31.2% [30.5 to 32.0]). The prevalence of myopia demonstrated a nonlinear distribution with the highest peak between the ages of 19 and 29 years. The prevalence of hyperopia decreased with age in subjects aged 39 years or younger and then increased with age in subjects aged 40 years or older. The prevalence of astigmatism gradually increased with age. Education was associated with all refractive errors; myopia was more prevalent and hyperopia and astigmatism were less prevalent in the highly educated groups.ConclusionsIn young generations, the prevalence of myopia in Korea was much higher compared to the white or black populations in Western countries and is consistent with the high prevalence found in most other Asian countries. The overall prevalence of hyperopia was much lower compared to that of the white Western population. Age and education level were significant predictive factors associated with all kinds of refractive errors.     

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.     

Does the level of physical activity in university students influence development and progression of myopia?--a 2-year prospective cohort study

PURPOSE: To study whether physical activity has a protective effect on the development and progression of myopia in medical students. METHODS: In a 2-year longitudinal cohort study, 156 Caucasian first-year medical students from the University of Copenhagen were enrolled. The baseline examination included visual acuity, subjective refraction, Maddox Wing test (Clement Clarke International Ltd., Harlow, UK), partial coherence interferometry, slit lamp examination, automated refraction in cycloplegia, an oral questionnaire, and a cycle ergometer test. Measurements were repeated at the follow-up. A total of 151 (97%) participants completed the study. RESULTS: The prevalence of myopia (spherical equivalent [SE] 相似文献   

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.     

Prevalence of refractive errors in a rural South Indian population

PURPOSE: To report the prevalence of refractive errors in a rural south Indian population. METHODS: Four thousand eight hundred subjects (age, >39 years) from rural south India were enumerated for a population-based study. All participants underwent complete ophthalmic evaluation. Subjects who were phakic in the right eye with best corrected visual acuity of 20/40 or better were included for analysis. Association of refractive errors with age, sex, cataract, and diabetes mellitus were analyzed. RESULTS: Of the 3924 responders, 2508 were eligible. The unadjusted prevalence of emmetropia (spherical equivalent [SE], -0.50 to +0.50 diopter sphere [DS]), myopia (SE < -0.50 DS), high myopia (SE < -5.00 DS), and hyperopia (SE > 0.50 DS) were 50.60%, 26.99%, 3.71%, and 18.70% and age and gender adjusted for the rural Tamil Nadu population were 46.77%, 30.97%, 4.32%, and 17.94%, respectively. The prevalence of emmetropia decreased significantly with age (P < 0.0001), and the prevalence of myopia and high myopia increased significantly with age (P < 0.001) and were significantly associated with nuclear sclerosis (P < 0.001). The prevalence of hyperopia increased until 60 years of age and then decreased. Hyperopia was more common among women than men (P < 0.001) and was negatively associated with nuclear sclerosis (P < 0.001) and positively with diabetes mellitus (P = 0.008). Of the participants with astigmatism (cylindrical error greater than 0.50 DC), 9.80% had with-the-rule (WTR) and 77.44% against-the-rule (ATR) astigmatism. The prevalence of WTR and ATR astigmatism significantly decreased (P < 0.001) and increased (P = 0.006) with age, respectively. CONCLUSIONS: The pattern of refractive errors in this rural south Indian population is similar to those reported in other tropical regions of the world.     

Distance refractive error among Aboriginal people attending eye clinics in remote South Australia

PURPOSE: To determine the prevalence of distance refractive error among Aboriginal people attending eye clinics in remote South Australia. METHODS: A clinic-based cross-sectional study was conducted that involved opportunistic sampling of Aboriginal people attending eye clinics in remote South Australia. There were 189 individuals who were invited to participate in the study all of whom underwent ophthalmic examination. This examination included measurement of pinhole-corrected visual acuity and non-cycloplegic autorefraction. RESULTS: Automated refractive error examinations were performed on 148 people within this sample. The mean age was 44.8 +/- 14.5 years and women comprised 57.7% of the sample. The overall mean refractive error was -0.01 +/- 1.8 D (SD). The prevalence of myopia (spherical equivalent (SE) < -0.5 D), high myopia (SE less than or equal to -6.0 D), hypermetropia (SE > 0.5 D), astigmatism (cylinder at least -0.5 D) and anisometropia (difference in SE of >0.5 D) was 31.1%, 0.7%, 33.1%, 55.8% and 45.9%, respectively. Further analyses revealed significant age-related trends with both myopia and hypermetropia. There were no gender associations with any form of refractive error. Of those people with clinically significant refractive error, 51/148 (34%), only four people owned distance spectacles. CONCLUSIONS: There continues to be a level of uncorrected distance refractive error within these patients. This represents a need to screen for refractive error among Aboriginal people in remote locations and to provide them with appropriate spectacle correction.     

A retrospective study of myopia progression in adult contact lens wearers

PURPOSE: To study retrospectively the frequency of myopia progression and risk factors for progression in a sample of adult contact lens wearers. METHODS: From a database of 815 soft contact lens wearers, patients were identified whose age was between 20 and 40 years, who had at least -0.50 D spherical equivalent of myopia in both eyes, three or more refractions, and > or =5 years of follow-up. Only data from the right eye were used. Progression was defined as an increase of at least -1.00 D over 5 years. Subjects were also asked to complete a questionnaire regarding their ocular history, demographics, family history, and the amount of time spent performing different tasks at home and at work. RESULTS: Two hundred ninety-one subjects met the eligibility criteria with a mean baseline refractive error of -3.29 +/- 1.92 D and a mean age of 28.5 +/- 5.0 years. Of these, 21.3% progressed by at least -1.00 D over the 5-year period. The 5-year rate of progression decreased with increasing age (chi(2) = 12.44, P = 0.006). One hundred ninety-seven subjects (67.6%) completed and returned questionnaires. "Progressors" (N = 41) did not differ from "nonprogressors" (N = 156) in terms of hours per day spent reading and writing, computer use, education level, family history of myopia, age of onset of myopia, and contact lens wear. CONCLUSIONS: In this database of soft contact lens wearers, myopia progression was common for subjects in their twenties and less common for those in their thirties.     

Prevalence of refractive errors in school-age children in Morocco

Background:  The prevalence of refractive errors in school-age children in Morocco was assessed.
Methods:  A total of 545 children (300 boys and 245 girls, between 6 and 16 years of age) attending school were examined to assess their refractive errors in a field study in Morocco (North Africa). The examination included autorefraction under cycloplegia and visual acuity, stereopsis and anterior corneal-radius measurements .
Results:  We found a low prevalence of myopia (≤−0.5 D SE [spherical equivalent] in at least one eye), i.e. only 6.1%. The prevalence of hyperopia (≥2.0 D SE in at least one eye) was 18.3%. Astigmatism (≤−0.75 D of cylinder in at least one eye) was found in 23.5% of these children. The low prevalence of large refractive errors makes visual acuity in these children very good. In general, the corneal radii did not significantly vary with age. There were no significant differences between the distribution of refractive errors in these children according to gender but there were with respect to age.
Conclusions:  There was a low prevalence of myopia in these African children, astigmatism being the most frequent refractive error. The mean refractive errors found were low, and therefore visual acuity was high in these children.     

A cohort study of incident myopia in Singaporean children

PURPOSE: To determine the risk factors of incident myopia in a school-based cohort study in Singaporean children. METHODS: A 3-year prospective cohort study was conducted in Singaporean school children aged 7 to 9 years in three schools at entry. Chinese children without myopia at baseline (n = 994) were included in the analysis. The main outcome was incident myopia, defined as spherical equivalent (SE) at least -0.75 D based on cycloplegic autorefraction. Other definitions of incident myopia, at least -0.5 D and at least -1.0 D, were also assessed. RESULTS: After controlling for school, age, gender, income, reading in books per week and intelligence quotient (IQ) test scores, we found the relative risk (RR) of incident myopia defined as -0.75 D to be 1.55 (95% confidence interval [CI] 1.18-2.04) for two versus no myopic parents. The multivariate RR of myopia for IQ in the third versus first tertile was 1.50 (95% CI, 1.19-1.89). However, the RR of incident myopia was 1.01 (95% CI, 0.97-1.05) for every unit increase in books read per week. Similar results were obtained with definitions of -0.5 and -1.0 D for incident myopia. CONCLUSIONS: These data provide new prospective evidence of essential links between parental myopia, IQ scores and subsequent myopia development. However, reading in books per week was not associated with incident myopia.     

Prevalence rate of myopia in schoolchildren in rural Mongolia.

PURPOSE: The prevalence of myopia among some young Asian populations has been reported to be increasing to near epidemic proportions. Mongolia is an emerging Asian economy with limited ophthalmic resources. The purpose of this study was to define a level of myopia for school-aged children in rural Mongolia. METHODS: A total of 1057 schoolchildren, aged between 7 and 17 years, were examined in two remote, rural suums (districts) of Mongolia: one situated in the western aimag (province) of Khovd and the other in the central steppe's aimag of Zavkhan. The examination included retinoscopy, subjective refraction, best-corrected visual acuity, and direct ophthalmoscopy. RESULTS: The total prevalence of myopia (more than -0.5 D spherical equivalent) was 5.8% (95% confidence intervals [CIs], 4.4-7.2%). Female students exhibited a significantly higher prevalence of myopia in comparison to male students: 8.3% (95% CIs, 6.0-10.6%) compared with 3.1%, respectively (95% CIs, 1.6-4.6%): p < 0.001). For those with myopia, the median level of myopia for both genders was -0.75 D spherical equivalent (SE) and ranged from -0.50 to -28.00 D SE in girls and from -0.50 to -6.50 D SE in boys. CONCLUSIONS: To the authors' knowledge, this is the first study to report a level of myopia for schoolchildren in Mongolia. The prevalence rate is low in comparison to reported studies for other Far Eastern countries.     

The changing prevalence of myopia in young adults: a 13-year series of population-based prevalence surveys

PURPOSE: To determine the changing prevalence of myopia during the years 1990 through 2002 among the 16- to 22-year age group and identify possible risk factors. METHODS: A retrospective study, based on 13 repeated prevalence surveys conducted over a 13-year period. The study subjects were all Israeli nationals belonging to the 16- to 22-year age group from the years 1990 to 2002. Refraction was determined by using subjective visual acuity followed by noncycloplegic autorefraction and subjective validation based on the autorefraction RESULTS: Mild myopia was defined as a refractive error of -0.50 to -3.00 D in at least one eye, moderate myopia as -3.25 to -6.00 D, and high myopia as more than -6.00 D. results. There were 919,929 subjects (382,139 [42%] females and 537,790 [58%] males) included in the study. The overall prevalence of myopia increased from 20.3% in 1990 to 28.3% in 2002. The prevalence of high, moderate, and mild myopia significantly increased in males from 1.7%, 5.7%, and 11.6% in 1990 to 2.05%, 7.2%, and 16.3% in 2002, respectively (P < 0.001). In females, the prevalence of myopia increased from 1.9%, 6.6%, and 13.5% in 1990 to 2.4%, 9.2%, and 20.7% in 2002, respectively (P < 0.001). A correlation between myopia and the number of years of education was observed. Non-Israeli origin was found to be a significant risk factor for myopia. CONCLUSIONS: During the 13 years from 1990 to 2002, the prevalence of myopia significantly increased among the Israeli population. Although there was an association with the level of education, gender, ethnicity, and origin, the prevalence of myopia increased on an annual basis, independent of these factors.     

广州市荔湾区学龄儿童屈光不正患病率的现况调查

目的 探讨广州市荔湾区5～15岁儿童的屈光不正患病率情况.方法 采用人群为基础的横断面调查方法.在2002年10月至2003年1月期间,中山大学巾山眼科中心对广州市荔湾区居住的全部5～15岁儿童,通过随机整群抽样和逐户登记确定样本与受检对象,在71个学校和19个社区检查点进行检查,眼部榆查包括视力、眼球运动、散瞳检影验光、自动验光、外眼、眼前段、屈光间质及眼底检查.屈光不正与儿童的年龄、性别及家长教育程度的关系采用多元回归模型进行分析.结果 在登记的5053名儿童中,实际检查4364人,受检率为86.4%.以等效球镜-0.50 D以下作为界定,近视的患病率为35.1%(95%可信区间:33.2%～36.9%),患病率从5岁的3.3%增加到15岁时的73.1%(根据检影验光);女性儿童具有较高的患病率,调整比数比为1.29(95%可信区间:1.11～1.51);以等效球镜+2.00 D以上作为界定,远视患病率为5.8%(95%可信区间:5.3%～6.3%),从5岁时16.7%减少到15岁时低于1.0%.散光(柱镜屈光度≥0.75 D)的患病率在视网膜检影法为33.6%,而在自动验光法为42.7%.Logistie回归模型显示近视与年龄(OR=1.52,95%可信区间:1.48～1.56)、女性(OR=1.29,95%可信区间:1.11～1.51)和父母教育程度(OR=1.22,95%可信区间:1.05～1.42)有关.结论 广州市荔湾区学龄儿童具有较高的近视患病率,近视已经成为重要的公共卫生问题,提高儿童屈光矫正的覆盖率和质量足当前的主要挑战.     

Ethnicity-specific prevalences of refractive errors vary in Asian children in neighbouring Malaysia and Singapore

AIM: To compare the prevalences of refractive errors in Malay, Chinese and Indian children in Malaysia and Singapore. METHODS: Children aged 7-9 years from three schools in the Singapore Cohort study of the Risk factors for Myopia (n = 1962) and similarly aged children from a random cluster sample in the metropolitan Kuala Lumpur area in the Malaysia Refractive Error Study in Children (n = 1752) were compared. Cycloplegic autorefraction was conducted in both countries. RESULTS: The prevalence of myopia (spherical equivalent of at least -0.5 diopters (D) in either eye) was higher in Singapore Malays (22.1%) than in Malays in Malaysia (9.2%; 95% confidence interval (CI) 11.2 to 14.7; p<0.001). Similarly, Singapore Chinese (40.1%) had higher prevalences than Malaysian Chinese (30.9%; 95% CI 1.5 to 16.9). Singapore Indians had a higher prevalence (34.1%) than Malaysian Indians (12.5%; 95% CI 17.4 to 25.9). The multivariate odds ratio of astigmatism (cylinder at least 0.75 D in either eye) in Singapore Malays compared with Malaysian Malays was 3.47 (95% CI 2.79 to 4.32). Ethnicity-specific hyperopia rates did not differ in Singapore and Malaysia. CONCLUSION: The ethnicity-specific prevalences of myopia in Singapore Malays, Chinese and Indians are higher than those in Malaysian Malays, Chinese and Indians. As Malays, Chinese and Indians in Malaysia have genetic make-up similar to that of Malays, Chinese and Indians in Singapore, environmental factors may contribute to the higher myopia rates.     

中山市2006～2007年中小学生近视调查分析

目的 探讨中山市中小学近视情况及相关因素.方法 采用随机整群抽样调查方法.在2006年至2007年期间,对中山市中小学通过随机抽样在市区和镇区6所学校(包括市区3所镇区3所)进行调查,采用问卷调查和散瞳验光检查其屈光度.各年级间及镇区与市区之间学生近视发病率采用卡方检验,近视率与用眼时间用相关系数分析.结果 此次调查对象共9379人,近视5443人,近视率58.03%,近视率从小学一年级8.04%上升到高三86.68%,市区和镇区小学近视率差异无统计学意义(P＞0.05),初中阶段市区近视率明显高于镇区(P＜0.01),高中阶段高三毕业班近视率明显高于高一高二非毕业班(P＜0.05镇区P＜0.001市区).此次调查中眼保健操对预防近视加深无明显作用(P0.05),每天看书总时间、一次持续看书时间、看课外书时间与近视发生呈正相关,相关系数分别为0.995、0.992、0.999.结论 中山市中小学生近视率较高,近视率与用眼时间密切相关.如何适当减轻学生的学习负担是预防近视的关键.     

Ethnic differences in refraction and ocular biometry in a population-based sample of 11-15-year-old Australian children

PURPOSE: To examine the prevalence of refractive error and distribution of ocular biometric parameters among major ethnic groups in a population-based sample of 11-15-year-old Australian children. METHODS: The Sydney Myopia Study examined 2353 students (75.3% response) from a random cluster-sample of 21 secondary schools across Sydney. Examinations included cycloplegic autorefraction, and measures of corneal radius of curvature, anterior chamber depth, and axial length. RESULTS: Participants mean age was 12.7 years (range 11.1-14.4); 49.4% were female. Overall, 60.0% of children had European Caucasian ethnicity, 15.0% East Asian, 7.1% Middle Eastern, and 5.5% South Asian. The most frequent refractive error was mild hyperopia (59.4%, 95% confidence interval (CI), 53.2-65.6), defined as spherical equivalent (SE) +0.50 to +1.99 D. Myopia (SE-0.50 D or less) was found in 11.9%, 95% (CI 6.6-17.2), and moderate hyperopia (SE> or =+2.00 D) in 3.5%, 95% (CI 2.8-4.1). Myopia prevalence was lower among European Caucasian children (4.6%, 95% CI 3.1-6.1) and Middle Eastern children (6.1%, 95% CI 1.3-11.0) than among East Asian (39.5%, 95%, CI 25.6-53.5) and South Asian (31.5%, 95%, CI 21.6-41.4) children. European Caucasian children had the most hyperopic mean SE (+0.82 D) and shortest mean axial length (23.23 mm). East Asian children had the most myopic mean SE (-0.69 D) and greatest mean axial length (23.86 mm). CONCLUSION: The overall myopia prevalence in this sample was lower than in recent similar-aged European Caucasian population samples. East Asian children in our sample had both a higher prevalence of myopia and longer mean axial length.     

Refractive error and ocular biometry in Jordanian adults

The aim of this study was to establish the prevalence of refractive errors in Jordanian adults of working age, and to study the ocular biometric correlates of refractive error in this population. Refractive error and ocular biometry were measured in 1093 Jordanian adult subjects aged 17-40 years to determine the prevalence of refractive error, and explore structural correlations of ametropia. Refractive error was measured using a Grand-Seiko GR-3100K closed-view infrared autorefractor. Ocular component measurements were made using A-scan ultrasonography and autokeratometry. The prevalence of myopia [spherical equivalent refraction (SER) less than -0.50 DS] and hyperopia (SER greater than +0.50 DS) was 53.71 and 5.67% respectively; 40.62% of the sample was emmetropic (refraction between +0.50 D and -0.50 D inclusive in both principal meridians). The distribution of SER was found to show marked leptokurtosis, exhibiting a peak between plano and 1 D of myopia. Corneal radius, anterior chamber depth, crystalline lens thickness, vitreous chamber depth and axial length (AL) parameters were normally distributed in the population studied. AL to corneal curvature ratio was not normally distributed, and showed marked leptokurtosis. Linear regression analysis showed that AL correlated most closely with spherical equivalent refractive error. This study has established a database of refractive error prevalence and ocular biometric correlates of ametropia in a Middle Eastern population of working age.