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.     

Prevalence of myopia among primary school children in eastern Sydney§

Background: Worldwide there is concern that the prevalence of myopia is increasing but the prevalence of myopia in Australian school children has not been analysed in detail. This study examines the prevalence of refractive errors in a large unselected population of primary school children in the eastern suburbs of Sydney. Methods: Children visiting the Vision Education Centre at the School of Optometry and Vision Science, University of New South Wales, on a school excursion during the first half of the 1990s were refracted by non‐cycloplegic retinoscopy. Spherical equivalents were computed and analysis of variance carried out. Results: There were 1,459 boys and 1,076 girls in the study, a total of 2,535 children of whom approximately 40 per cent were born overseas or were first generation Australians. Overall, there was no significant difference in refractive error between girls and boys, although there were age/gender interactions with older girls exhibiting more hyperopia than boys. The refractive error ranged from ‐0.25 to +1.25 D spherical equivalent in 87.3 per cent of children. Mean spherical equivalent for the group was +0.50 ± 0.82 D. There was a significant shift (p < 0.001) towards increasing myopia with age. The prevalence of myopia greater than ‐0.50 D rose from 1.0 per cent of four‐year‐olds to 8.3 per cent of 12‐year‐olds. Conclusions: The prevalence of myopia found in a large multiethnic group of nonclinical primary school children in eastern Sydney is lower than expected from other studies in the USA and Asia. Compared with Australian data from the 1970s and 198Os, only a weak increase in the prevalence of myopia is revealed.     

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.     

The incidence of refractive errors among school children in Hong Kong and its relationship with the optical components

This study aims to provide information about the prevalence of refractive errors among Chinese school children in Hong Kong, and its relationship with the optical components of the eye. Subjective refraction, corneal curvatures and ocular biometry were performed on 383 school children from age six to 17 years. The prevalence of myopia increases from 30 per cent at age six to seven to 50 per cent (girls) and 70 per cent (boys) at age 16–17. The mean spherical equivalent refraction gradually changes from plano at age six to seven to -2.00 D of myopia at age 1617. Our results are different from Caucasian data but comparable with those of other studies of Chinese in Asia. The increase in myopia correlates well with the axial length of the eye. Further studies are needed to investigate the cause for the development of myopia.     

A 2-year longitudinal study of myopia progression and optical component changes among Hong Kong schoolchildren.

This study investigated refractive error and optical component changes in a group of 142 Hong Kong schoolchildren from age 6 to 17 years over a 2-year period between 1991 and 1993. Subjects were refracted subjectively and corneal curvatures and ocular dimensions were measured. At the end of the 2-year study, the mean spherical equivalent refraction (SER) was -1.86 D (SD 1.99 D) and 62% of the schoolchildren were myopic. The annual incidence of myopia was 11.8%. Children aged 10 years and under had a greater change in SER toward myopia than older children. The annual rate of myopia progression for the myopic children was -0.46 D (SD 0.40 D) and the rate of progression was greatest between age 6 and 10 years old. Vitreous depth/axial length elongation was the main component contributing to the progression of myopia. Hong Kong schoolchildren develop myopia as early as 6 years old and myopia progresses at a greater rate compared with children of European extraction.     

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.     

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.     

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 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, incidence, and progression of myopia of school children in Hong Kong

PURPOSE: To determine the prevalence, incidence, and progression of myopia of Chinese children in Hong Kong. METHODS: A cross-sectional survey was initially conducted. A longitudinal follow-up study was then conducted 12 months later. RESULTS: A total of 7560 children of mean age 9.33 (95% confidence interval [CI] = 9.11-9.45; range, 5-16) participated in the study. Mean spherical equivalent refraction (SER) was -0.33 D (SD = 11.56; range, -13.13 to +14.25 D). Myopia (SER 相似文献   

Myopia prevalence in Chinese-Canadian children in an optometric practice.

PURPOSE: The high prevalence of myopia in Chinese children living in urban East Asian countries such as Hong Kong, Taiwan, and China has been well documented. However, it is not clear whether the prevalence of myopia would be similarly high for this group of children if they were living in a Western country. This study aims to determine the prevalence and progression of myopia in ethnic Chinese children living in Canada. METHODS: Right eye refraction data of Chinese-Canadian children aged 6 to 12 years were collated from the 2003 clinical records of an optometric practice in Mississauga, Ontario, Canada. Myopia was defined as a spherical equivalent refraction (SER) equal or less than -0.50 D. The prevalence of myopia and refractive error distribution in children of different ages and the magnitude of refractive error shifts over the preceding 8 years were determined. Data were adjusted for potential biases in the clinic sample. A questionnaire was administered to 300 Chinese and 300 Caucasian children randomly selected from the clinic records to study lifestyle issues that may impact on myopia development. RESULTS: Optometric records of 1468 children were analyzed (729 boys and 739 girls). The clinic bias adjusted prevalence of myopia increased from 22.4% at age 6 to 64.1% at age 12 and concurrently the portion of the children that were emmetropic (refraction between -0.25 and +0.75 D) decreased (68.6% at 6 years to 27.2% at 12 years). The highest incidence of myopia for both girls ( approximately 35%) and boys ( approximately 25%) occurred at 9 and 10 years of age. The average annual refractive shift for all children was -0.52+/-0.42 D and -0.90+/-0.40 D for just myopic children. The questionnaire revealed that these Chinese-Canadian children spent a greater amount of time performing near work and less time outdoors than did Caucasian-Canadian children. CONCLUSIONS: Ethnic Chinese children living in Canada develop myopia comparable in prevalence and magnitude to those living in urban East Asian countries. Recent migration of the children and their families to Canada does not appear to lower their myopia risk.     

Refractive error in Chinese with type 2 diabetes and its association with glycaemic control

Background

The aim of this study was to determine the prevalence of refractive errors and their association with glycaemic control among adults with type 2 diabetes mellitus (T2DM) in eastern China.

Methods

A community‐based survey, including 913 adults with T2DM aged 30 to 89 years, was conducted. Refractive error was assessed by autorefraction, after which subjective refraction was performed. Ocular biometric parameters were measured by non‐contact partial coherence laser interferometry. Myopia was defined as spherical equivalent (SE) less than ?0.50 dioptres (D), high myopia as SE less than ?5.00 D, hyperopia as SE greater than 0.50 D and astigmatism as cylinder less than ?0.50 D.

Results

After excluding participants who had undergone cataract surgery, 839 were included in the data analyses and 96.1 per cent were found to have refractive errors. The overall prevalences of myopia, high myopia, hyperopia and astigmatism were 28.2 per cent (95 per cent confidence interval [CI] 25.2–31.3), 6.3 per cent (95 per cent CI 4.7–8.0), 46.4 per cent (95 per cent CI 43.0–49.7) and 81.0 per cent (95 per cent CI 78.4–83.7) with no gender differences observed (all p > 0.10). In multivariate analysis, myopia was associated with decreasing age (odds ratio [OR] = 0.86, p = 0.01; per year increase), higher blood levels of haemoglobin A_1c (HbA_1c) (OR = 1.12, p = 0.05; per unit increase), higher education levels (OR = 5.10, p < 0.001; university or college versus illiterate or primary school) and the presence of nuclear cataract (OR = 2.36, p < 0.001).

Conclusions

Refractive errors may be associated with glycaemic control among T2DM patients. Longitudinal analyses are warranted to examine the relationship between changes in HbA_1c and the development of refractive errors.

     

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.     

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.     

Annual Incidences and Progressions of Myopia and High Myopia in Chinese Schoolchildren Based on a 5-Year Cohort Study

PurposeTo determine the annual incidences and rates of progression of myopia and high myopia in Chinese schoolchildren from grade 1 to grade 6 and explore the possible cause-specific risk factors for myopia.MethodsFrom 11 randomly selected primary schools in Anyang city, central China, 2835 grade 1 students were examined with annual follow ups for 5 years. Students were invited to undergo a comprehensive examination, including cycloplegic autorefraction, ocular biometry, and standardized questionnaires.ResultsThe mean spherical equivalent refraction decreased substantially from +0.94 ± 1.03 diopter (D) in grade 1 to −1.37 ± 2.08 D in grade 6, with rapid annual myopic shifts, especially for students in grades 3 through 6 (−0.51 to −0.59 D). The prevalence of myopia increased substantially, with the yearly incidence of myopia increasing from 7.8% in grade 1 and 2 to 25.3% in grades 5 and 6, and the incidence of high myopia increased from 0.1% to 1.0%. The 5-year incidence of myopia was lowest among children who has a baseline spherical equivalent refraction of greater than +2.00 D (4.4%), and increased to nearly 92.0% among children whose baseline spherical equivalent refraction was 0.00 to −0.50 D. The incidence of myopia was higher in children who had less hyperopic baseline refraction, two myopic parents, longer axial length, deeper anterior chamber, higher axial length–corneal radius of curvature ratio, and thinner lenses.ConclusionsBoth the annual incidence and progression rates of myopia and high myopia were high in Chinese schoolchildren, especially after grade 3. Hyperopic refraction of children should be monitored before primary school as hyperopia reserve to prevent the onset of myopia and high myopia.     

Prevalence of refractive errors in Villa Maria,Córdoba,Argentina

Background: Refractive errors are among the most frequent reasons for demand of eye-care services. Publications on refractive errors prevalence in our country are few. This study has the purpose to assess the prevalence of refractive errors in an adult population of Villa Maria, Córdoba, Argentina. Methods: The Villa Maria Eye Study is a population-based cross-sectional study conducted in the city of Villa Maria, Córdoba, Argentina from May 2008 to November 2009. Subject’s aged 40+ received a demographic interview and complete ophthalmological exam. Visual acuity was obtained with an ETDRS chart. Cycloplegic auto refraction was performed. The spherical equivalent was highly correlated between right and left eyes, so only data of right eyes are presented. Myopia and hyperopia were defined with a ±0.50 diopters (D) criterion and astigmatism >1 D. Results: This study included 646 subjects, aged 40 to 90 (mean age: 59.6±10.3 years old). Four hundred and sixty two (71.5%) were females. The mean spherical equivalent was +0.714±2.41 D (range, ?22.00 to+8.25 D) and the power of the cylinder was, on average, ?0.869±0.91 D (range, 0 to ?6.50 D). In this sample, 61.6% subjects were hyperopic, and 13.5% were myopic. Myopia prevalence was lower in men (9.8% versus 14.9%) but this difference among genders was not statistically signiifcant. There were 141 subjects (21.8%) with anisometropia greater than 1 D, and 168 subjects (26.0%) with astigmatism greater than 1 D. Conclusions: The present study shows the prevalence of cycloplegic refractive errors in an adult population of Argentina. The prevalence of hyperopia was high, while myopia prevalence was very low.     

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.     

屈光性调节性内斜视儿童戴镜后的屈光演变

目的探讨屈光性调节性内斜视儿童戴镜后屈光状态随年龄的变化规律,为临床随访时间及配镜提供依据。方法回顾我院65例（130眼）屈光性调节性内斜视儿童连续多年的屈光数据,对主导眼和非主导眼的屈光度比较采用配对t检验,对屈光度差值与观察期进行直线回归分析。结果等效球镜度、球镜度、散光度差值与月龄存在直线回归关系（P〈0．01）。主导眼和非主导眼等效球镜度月平均分别减少0．015 D和0．012 D;等效球镜度改变规律为远视度先增加后减少,而后有逐渐向近视方向发展的趋势;转变年龄为3．58～4．90岁;散光度月平均演变速度仅为0．002 D。结论屈光性调节性内斜视儿童戴镜后屈光状态随着年龄的增长,远视度先增加后减少,而后有逐渐正视化趋势：年均改变速度〈0．25 D。     

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.     

Prevalence of myopia and hyperopia in a population of Polish schoolchildren

PURPOSE: The aim of this study was to determine the prevalence of myopia and hyperopia in a population of Polish schoolchildren. METHODS: A total of 4422 students were examined (2107 boys and 2315 girls, aged 6-18 years, mean age 11.1, S.D. 3.5). The examination included retinoscopy under cycloplegia induced with 1% tropicamide. Myopia was defined as a spherical equivalent (SE) of at least -0.5 dioptres (D), and hyperopia as a SE of at least +1.0 D. Data analysis was performed using Spearman's rank correlation coefficients and chi-squared test; p-values of <0.05 were considered statistically significant. RESULTS: It was observed that 13.3% of Polish students in the age group ranging from 6 to 18 years were myopic while 13.1% of students were hyperopic. Furthermore, a positive correlation was found between the prevalence of myopia and age (p < 0.001) and a negative correlation between prevalence of hyperopia and age (p < 0.001). It was observed that the prevalence of myopia increases substantially between 7 and 8 years of age (p < 0.01). Moreover, it was determined that with age the average refractive error among schoolchildren becomes more myopic (p < 0.001). CONCLUSIONS: The occurrence, degree and progress of myopia and hyperopia in Poland is similar to that in other European countries with a predominantly Caucasian population.