Prevalence Rate Of Myopia Research Articles

The relationship between vision status and its influencing factors among primary and secondary school students: The masking effect of physical activity level and the moderating effect of academic stress

BackgroundThe global youth myopia rate continues to rise, and the vision health of primary and secondary school students has become a global concern. This cross-sectional study aims to explore the vision status of primary and secondary school students in the Ningxia Hui Autonomous Region, China, and its internal relationship with influencing factors under regional characteristics.MethodsA survey was conducted among 1,670 primary and secondary school students in the Ningxia Hui Autonomous Region of China using a snapshot method and random sampling techniques from September to October 2023. The survey instruments included vision examination, the International Physical Activity Questionnaire, the Lifestyle Behavior Scale, and the Student Academic Stress Questionnaire. The data was tested with descriptive statistics, difference test, correlation analyses, regression analyses, and so on using SPSS 25.0 and SPSSAU, and the target model was established and tested for the goodness-of-fit with AMOS 23.0.ResultsThere was a significant negative correlation between vision status and lifestyle behaviors (r=-0.360, p < 0.01), physical activity level (r=-0.058, p < 0.05). The physical activity level played a significant masking effect between lifestyle behaviors and vision status (a*b = 0.002, c’=-0.044), and academic stress played a moderating role in the process of lifestyle behaviors affecting physical activity level and vision status. A moderated mediator model was constructed and fitted well (RMSEA = 0.028, CFI = 0.953, NFI = 0.934).ConclusionsThe prevalence rate of myopia among primary and secondary school students in Ningxia Hui Autonomous Region is lower than the national average, and its prevalence is related to lifestyle behaviors, physical activity level, and academic stress. The impact of lifestyle behaviors on vision status is controlled by physical activity level and academic stress. A strategy of coordinated education involving families, schools, and communities should be implemented. Parents should avoid having excessive expectations and additional academic burdens on their children and encourage them to actively participate in sports; schools should fully implement the ‘’Double Reduction’’ policy, making myopia prevention and control an important part of health education; communities should carry out publicity work for myopia prevention and control, raising adolescents’ awareness of eye health.

A clearer vision: unveiling the importance of cycloplegic refraction and the pseudomyopia prevalence in Chinese preschoolers

BackgroundThis study aimed to investigate the difference between cycloplegic and noncycloplegic refraction and evaluate the pseudomyopia prevalence in Chinese preschool children during the outbreak of COVID-19.MethodsA cross-sectional study was conducted in the Tongzhou District of Beijing, China. Refractive error was measured under both noncycloplegic and cycloplegic conditions with autorefraction. The difference between noncycloplegic and cycloplegic spherical equivalent refraction (SER) and pseudomyopia prevalence were analyzed. Pseudomyopia was defined as SER ≤-0.50D in precycloplegic assessments and >-0.50D in post-cycloplegic assessments.ResultsOut of the 1487 participants who were enrolled in the study, 1471 individuals (98.92%) between the ages of 3–6 years completed all required procedures. A statistically significant difference in refraction was observed between noncycloplegic and cycloplegic measurements, the median of difference in spherical equivalent refraction (SER) of 0.88D (dioptre)(0.50,1.38). There was a high intraclass correlation (ICC) between these two methods for cylinders (ICC = 0.864; 95% CI, 0.850–0.877). The median DSE for myopia, emmetropia and hyperopia were 0.25D (0.00, 0.38),0.25D (0.06, 0.50) and 1.00D (0.62, 1.38), an hypermetropes showed considerably greater differences than myopes and emmetropes (Kruskal-Wallis test, H = 231.023, P = 0.000). Additionally, girls displayed a greater DSE than boys. Furthermore, when comparing against-the-rule (ATR) and oblique astigmatism, it was found that with-the-rule (WTR) astigmatism had the largest DSE. The study found varying prevalence rates of myopia, emmetropia, and hyperopia with and without cycloplegia, which were 1.90% vs. 10.06%, 11.49% vs. 50.31%, and 86.61% vs. 39.63%, respectively. Additionally, the overall prevalence of pseudomyopia was determined to be 8.29%. Participants with pseudomyopia had a significantly higher mean difference in SER (DSE) compared to non-pseudomyopic participants.ConclusionsCycloplegic refraction is more sensitive than a noncycloplegic one for measuring refractive error in preschool children. Pseudomyopia is prevalent in preschool children during the COVID-19 outbreak period. Our study indicates the possibility that cycloplegic refraction should be performed in preschool children routinely.

Survey on pattern of myopia in school children in Hangzhou after the COVID-19 pandemic: a school-based vision screening study

BackgroundMyopia is a major health issue around the world. Myopia in children has increased significantly during the COVID-19 pandemic in China, but reports are scarce on the prevalence of myopia following the pandemic. This study collected vision screening data of school children in China for five consecutive years to observe the changes in myopia after the pandemic and compare the observed prevalence of myopia before and after the pandemic.MethodsA school-based vision screening study used stratified samplings to collect the vision screening data in school children aged 6–13 from 45 primary schools in Hangzhou. Vision screening data including uncorrected visual acuity(UCVA) and spherical equivalent refraction(SER). Calculating the mean of SER and the prevalence of myopia and hyperopia from 2019 to 2023.ResultsA total of 79,068 screening results (158,136 eyes) were included in the analysis. A substantial myopic shift (approximately -0.30 diopters [D] on average) was found in 2020 and 2021 compared with 2019 in all age groups and a substantial myopic shift (approximately 0.4 D on average) was found in 2022 compared with 2021. A slight myopic shift (approximately -0.14 D on average) was found in 2023 compared with 2022. The prevalence of myopia in all age groups was the highest for five years in 2020 or 2021, which was 31.3% for 6-year-olds, 43.0% for 7-year-olds, and 53.7% for 8-year-olds. A positive change in the prevalence rate of myopia was found at 6 years old (0.59%, 0.12%, 0.36%, 0.25%, p < 0.001). The change in prevalence rate in myopia was shifted slightly in children aged 10–13 years. Children aged 8 to 13 years had a slight increase in myopia prevalence from 2022 to 2023. The prevalence of hyperopia was low and stable in all grade groups, ranging from 0.7% to 2.2% over five years.ConclusionMyopia in children has increased rapidly during the COVID-19 pandemic. After the pandemic, the prevalence of myopia in children gradually decreased temporarily and then rebounded. Myopic shift was more apparent in younger children. Myopic shift in children may be related to the reduction of outdoor time, less light, and near work habits, and further research is needed.

Analysis of risk factors associated with pre-myopia among primary school students in the Mianyang Science City.

Objectives To find out the prevalence rate of pre-myopia among primary school students in the Mianyang Science City Area, analyze its related risk factors, and thus provide a reference for local authorities to formulate policies on the prevention and control of myopia for primary school students. Methods From September to October 2021, Cluster sampling was adopted by our research group to obtain the vision levels of primary school students employing a diopter test in the Science City Area. In addition, questionnaires were distributed to help us find the risk factors associated with pre-myopia. Through the statistical analysis, we identify the main risk factors for pre-myopia and propose appropriate interventions. Results The prevalence rate of pre-myopia among primary school students in the Science City Area was 45.27% (1020/2253), of which 43.82% were boys and 46.92% were girls, with no statistically significant difference in the prevalence rate of myopia between boys and girls (2 =2.171, P=0.141). The results of the linear trend test showed that the prevalence rate of pre-myopia tends to decrease with increasing age (Z=296.521, P=0.000). Logistic regression analysis demonstrated that the main risk factors for pre-myopia were having at least one parent with myopia, spending less than 2 hours a day outdoors, using the eyes continuously for more than 1 hour, looking at electronic screens for more than 2 hours, and having an improper reading and writing posture. Conclusion The Science City Area has a high prevalence rate of pre-myopia among primary school students. It is proposed that students, schools, families, and local authorities work together to increase the time spent outdoors, reduce digital screens and develop scientific use of eye habits.

Prevention and public awareness of myopia

Myopia has become a Public Health issue, with prevalence rates that depend on age and geographical area, reaching the highest values in Asia. Thus, a recent review on the prevalence of myopia in children, measured with cycloplegia, established that the prevalence ranges from 10% in Africa to 60% in Asia, increasing in all areas every year. These results show the importance of taking action to prevent myopia.The main factors with strong scientific evidence to prevent myopia are increasing outdoor time and decreasing near‐work activities.Public awareness is an essential factor to stop the increase in the prevalence rates of myopia. However, the increase in scientific literature does not give us information about the sensitivity of the general population on a specific topic.Through the internet search trends analysis, we can find out how much interest myopia has in the population, analysing the most concerned countries and how the related queries are being carried out and increased.Thus, if we look for the search trends with the word “myopia” as “term search” in the last 10 years, we can see how the number of searches is increasing, reaching the maximum in 2022. China, Taiwan, and Hong Kong lead the searches on the Internet, reflecting how the higher prevalence in these areas has generated a greater concern. Concerning related queries, we find a high growth in interest caused by the inclusion of myopia among the diseases of the international classification of diseases of the World Health Organization, ICD 10, with an increase of 2000% in the searches. This search suggests that people interested in myopia are looking for reliable sources to collect information. Finally, it is remarkable that in the review of the related queries, we did not find the term prevention among the most performed searches, and treatment, cure, or control are queries that are in positions 20, 21, and 26 of those searches.Compared with other of the most established eye pathologies in society, we can see as myopia is still behind them. For instance, if we compare the searches of the term myopia, with glaucoma or cataract, 61% of the web searches are related to glaucoma, 43% to cataracts, and only 16% corresponded to myopia.In conclusion, even though scientific evidence alerts us about the increase in the rates of myopia and the importance of working on its prevention, there is still a long way to reach society to generate a clear awareness of myopia and the consequences of not taking action to prevent it.

Myopia prevalence, refractive status and uncorrected myopia among primary and secondary school students in Germany.

The increasing prevalence of myopia worldwide is problematic because myopia can result in severe secondary pathologies, and is associated with considerable financial burden. With plenty of prevalence data available for some regions, current data for Europe remain sparse. Yet, information on myopia prevalence and associations is essential for monitoring, preventive and interventive purposes. Likewise, uncorrected refractive errors are also critical, as they can, e.g., affect educational outcomes, making information on uncorrected myopia valuable for diagnostics and health education. We performed non-cycloplegic autorefraction on two samples in Germany. The younger sample included 489 primary school students (grades 3-4, mean age: 9.30 ± 0.78 years), the older sample 1,032 secondary school students (grades 8-10, mean age 14.99 ± 1.12 years). These samples mark the limits of the age range during which school myopia usually emerges. Myopia (spherical equivalent ≤ -0.75D) prevalence was 8.4% in the younger sample and 19.5% in the older sample. The prevalence was generally higher in higher grade levels, with the most notable difference between grades 8 and 9. Females were more myopic than males in all grades except grade 3, with the largest gender difference in grade 10. The older sample also exhibited a more myopic spherical equivalent than the younger sample. In the older sample, spherical equivalent was more myopic in females than in males, and in grade 9 and 10 participants more than in grade 8 participants. Rates of uncorrected myopia were extremely high: 51.2% in the younger sample and 43.3% in the older sample. The obtained myopia prevalence rates are generally consistent with other European studies, as is the higher prevalence in female than male adolescents, accelerating with age. The high rates of uncorrected myopia warrant further investigation and should inform public health policies, including the implementation of regular refractive screenings.

Trends in Myopia and High Myopia from 1966 to 2019 in Olmsted County, Minnesota

PurposeTo investigate the prevalence of myopia and high myopia in Olmsted County, Minnesota from 1966-2019. DesignRetrospective cross-sectional, trend study using a random population-based sample in Olmsted County, Minnesota from 1966-2019. MethodsManifest refractions or lens prescription were converted to spherical equivalent (SE) to estimate prevalence of adult myopia and high myopia. Age, sex, race, and visual acuity were recorded. Subjects with SE ≤-0.5 diopters (D) were considered myopic; ≤-6.0 D were considered high myopia. Exclusion criteria included visually significant cataract, pseudophakia, prior refractive surgery, or age <18 years-old. ResultsAmong 81,706 sampled subjects, myopia prevalence increased from 33.9% (95% CI 31.1-36.8) in 1960s to 57.1% (95% CI, 56.6-57.6) in 2010s (p<0.001). High myopia prevalence increased from 2.8% (95% CI, 1.95-3.98) in 1960s to 8.3% (95% CI, 8.08-8.62) in 2010s (p<0.001). Both males (32.0%-55.1%, p<.001) and females (40.6%-58.5%, p<.001) experienced increasing myopia prevalence from 1960s-2010s while males (2.6%-7.4%, p<.001) and females (3.4%-9.1%, p<.001) also had higher high myopia prevalence rates from 1960s through 2010s. Increasing myopia and high myopia prevalence was detected by decade in nearly all age groups (excluding 18-24-year-old high myopia subjects). White and Asian subjects had the highest myopia prevalence while Black subjects had the lowest. From the 2000s-2010s, White (53.3%-57.0%, p<0.001) and Black (41.0%-47.0%, p=0.001) subjects had significant increases in myopia prevalence. Mean SE decreased from the 1960s (-0.42 D; 95% CI -0.59-+2.49) to 2010s (-1.85 D; 95% CI, -1.88-+2.96) (p<0.001). ConclusionsFrom 1966-2019 in Olmsted County, Minnesota, there was a 68% and 199% increase in myopia and high myopia prevalence, respectively.

The Prevalence and Progression of Myopia in Elementary School Students in Shanxi Province, China During the COVID-19 Pandemic

ABSTRACTPurposeTo investigate the prevalence of myopia and the risk factors associated with its progression in elementary school students during the COVID-19 pandemic in Shanxi Province, China.MethodsThe investigation included 960 students spanning first to sixth grade from six elementary schools in Shanxi Province, China. All participants received non-cycloplegic refraction and vision tests in December of 2019 (before the COVID-19 pandemic) and in June of 2020 (after classes resumed). Information concerning the students’ eye-use behaviors, physical activities, diet and sleep during the pandemic was collected using a questionnaire survey. A total of 913 students (457 males) completed all tests and the questionnaire.ResultsThe overall prevalence rate of myopia was 16.6% in December of 2019, and it increased with age. There was no gender difference in the prevalence of myopia (χ2 = 3.210, P = .073), but females exhibited a lower average spherical equivalent (SE) (P = .026). When the classes were resumed 6 months later, the overall prevalence rate of myopia was found to be 39.4%, which was significantly higher than it before the pandemic (χ2 = 117.425, P < .001). The average SE of the participants was −0.95D, which was significantly lower than the average SE (−0.43D) before the pandemic (P < .001). SE variation (ΔSE) in grade 6 was significantly higher than that in grade 1. No significant difference in ΔSE was found between males and females. Analyses of ordinary least squares (OLS)-estimated linear, natural logarithmic and quadratic functions revealed that the progression of myopia during the COVID-19 pandemic was significantly correlated with screen time, types of electronic devices, the amount of sleep, age, and the number of parents with myopia.ConclusionsThe prevalence rate and progression of myopia among elementary school students in Shanxi Province increased significantly during the COVID-19 pandemic, which was likely related to China’s home-based online learning programs. Therefore, it is necessary to optimize the educational programs for elementary school students when they study at home. We recommend increased time for outdoor activities and limiting screen time.

Refractive Errors in Medical Students in a Teaching Hospital

Refractive errors are contributing to a severe public health problem. The increasing prevalence rates of myopia have reached epidemic levels in several areas. This study aimed to determine the prevalence rates of refractive errors in medical students

The Prevalence of Myopia in Children in Spain: An Updated Study in 2020.

Background: In recent years, there was a significant increase in myopia incidence worldwide. However, it is still not clear how it affects Spanish children. Since 2016, this research team analyzed myopia prevalence and risk in 9668 children aged between 5 and 7 years. It was shown that the prevalence rates increased from 16.8% in 2016 to 20.4% in 2019. The objective of this study is to update the prevalence rate of myopia in Spain in 2020 and analyze the risk and prevention factors of myopia. Methods: The participants underwent an optometric examination, and a questionnaire on their lifestyle, family history, and geographical origin was carried out. Finally, data were analyzed using the SPSS version 27 program. Results: 1601 children from various Autonomous Communities of Spain were examined. In 2020 the myopia rates did not increase compared to 2019 (p < 0.05), although the number of hyperopes decreased and the number of emmetropes increased. Regarding age, the prevalence of myopia increased progressively over the years (p < 0.001). There was no association between gender and myopia (p > 0.05). There was a link between the time spent in near vision and family history with the prevalence of myopia (p < 0.05). Conclusions: The prevalence of myopia in Spain in children between 5 and 7 years old increased significantly between 2016 and 2020.

Refractive errors and risk factors for myopia in infants aged 1\u201318 months in Tianjin, China

BackgroundInfancy is the of a child’s visual development. Refractive errors, especially myopia, are a common vision disorder. Thus, the purpose of this study was to explore refractive errors and risk factors for myopia among infants aged 1–18 months in Tianjin, China.MethodsA total of 583 infants aged 1–18 months participated in this cross-sectional study at Tianjin Women’s and Children’s Health Center in China from February 2019 to November 2020. Each infant received a complete ophthalmologic examination, and myopia-related risk factors were investigated using a questionnaire.ResultsA total of 583 eligible infants participated in this study, including 312 (53.5%) boys and 271 (46.5%) girls. There were 164 (28.1%) premature born infants. The mean age was 6.59 ± 4.84 months (range, 1–18 months). The mean spherical equivalent (MSE) for the right eye was 1.81 D ± 1.56 D, with no difference related to sex (P = 0.104). Refractive state showed an average hyperopia of +2.74 ± 1.74 D at early ages, followed by a trend toward less hyperopia, finally reaching +1.35 ± 1.44 D at the age of 18 months (P ≤0.001). The overall prevalence rates of myopia (MSE ≤ −0.50 D), emmetropia (−0.50 D<MSE<+0.50 D), hyperopia (MSE ≥ +2.00 D), and astigmatism (≥ 1.50 D) were 5.1%, 10.8%, 42.7%, and 49.9%, respectively. The chi-square tests showed that gender, gestational age ≥37 weeks, winter birth, prenatal exposure to environmental tobacco smoke, and parental history of high myopia were associated with children’s myopia (P = 0.022, P = 0.023, P = 0.038, P = 0.015, P<0.001, respectively).ConclusionsAmong Chinese infants in Tianjin, hyperopia and astigmatism were the most frequent refractive errors, and the diopter was lower in individuals with higher age. In a small number of infants with myopia, genetic factors and the prenatal environment were associated with the early onset of myopia.

Axial length and its associations in the Ural Very Old Study

To assess the distribution of axial length as surrogate for myopia and its determinants in an old population, we performed the Ural Very Old Study as a population-based cohort study. Out of 1882 eligible individuals aged 85 + years, the Ural Very Old Study performed in an urban and rural region in Bashkortostan/Russia included 1526 (81.1%) individuals undergoing ophthalmological and medical examinations with sonographic axial length measurement. Biometric data were available for 717 (47.0%) individuals with a mean age of 88.0 ± 2.6 years (range 85–98 years; 25%). Mean axial length was 23.1 ± 1.1 mm (range 19.37–28.89 mm). Prevalences of moderate myopia (axial length 24.5–< 26.5 mm) and high myopia (axial length ≥ 26.5 mm) were 47/717 (6.6%; 95% CI 4.7, 8.4) and 10/717 (1.4%; 95% CI 0.5, 2.3), respectively. In multivariable analysis, longer axial length was associated (coefficient of determination r2 0.25) with taller body height (standardized regression coefficient beta:0.16;non-standardized regression coefficient B: 0.02; 95% confidence interval (CI) 0.01, 0.03; P < 0.001), higher level of education (beta: 0.12; B: 0.07; 95% CI 0.02, 0.11; P = 0.002), and lower corneal refractive power (beta: − 0.35; B: − 0.23; 95% CI − 0.28, − 0.18; P < 0.001). Higher prevalence of moderate myopia, however not of high myopia, was associated with higher educational level (OR 1.39; 95% CI 1.09, 1.68; P = 0.007) and lower corneal refractive power (OR 0.77; 95% CI 0.63, 0.94; P = 0.01). In this old study population, prevalence of moderate axial myopia (6.6% versus 9.7%) was lower than, and prevalence of high axial myopia (1.4% versus 1.4%) was similar as, in a corresponding study on a younger population from the same Russian region. Both myopia prevalence rates were higher than in rural Central India (1.5% and 0.4%, respectively). As in other, younger, populations, axial length and moderate myopia prevalence increased with higher educational level, while high myopia prevalence was independent of the educational level.

Influence of the interaction between parental myopia and poor eye habits when reading and writing and poor reading posture on prevalence of myopia in school students in Urumqi, China

BackgroundTo evaluate the prevalence of myopia in school students in Urumqi, China, and explore the influence of the interaction between parental myopia and poor reading and writing habits on myopia to identify the at-risk population and provide evidence to help school students avoid developing myopia.MethodsA cross-sectional survey was conducted with 6,883 school students aged 7–20 years in Urumqi in December 2019. The Standard Eye Chart and mydriatic optometry were used to determine whether students had myopia. Falconer’s method was used to calculate the heritability of parental myopia. Multivariate unconditional logistic regression models were used to analyze the risk factors for myopia and the additive and multiplicative interaction of parental myopia and poor reading and writing habits.ResultsAfter standardizing the age of the 6,883 students, the overall prevalence rate of myopia was 47.50 %. The heritability of parental myopia was 66.57 % for boys, 67.82 % for girls, 65.02 % for the Han group, and 52.71 % for other ethnicities. There were additive interactions between parental myopia and poor reading and writing habits; among them, parental myopia and poor eye habits when reading and writing (the distance between the eyes and book is less than 30 cm when reading and writing, fingers block the sight of one eye while holding the pen, and leaning one’s body when reading and writing; habit 1) increased the risk of myopia by 10.99 times (odds ratio [OR] = 10.99, 95 % confidence interval [CI] = 8.33–14.68), parental myopia and poor reading posture (reading while lying down, walking, or in the car; habit 2) increased the risk of myopia by 5.92 times (OR = 5.92, 95 % CI = 4.84–7.27). There was no multiplicative interaction between parental myopia and habit 1 or habit 2 (OR = 0.69, 95 % CI = 0.44–1.08; OR = 0.89, 95 % CI = 0.66–1.21, respectively).ConclusionThe prevalence of myopia among students in Urumqi, Xinjiang is relatively high. The risk of developing myopia is affected by parental myopia and poor reading and writing habits. In addition, parental myopia amplifies the harm caused by poor reading and writing habits, thereby increasing the risk of myopia. Students with parents who have myopia should be targeted during myopia prevention efforts.

Refractive status in a German pediatric cohort: A cross-sectional Analysis of the LIFE Child data

Purpose. Current prevalence rates of myopia in children and adolescents vary all over the world, with especially high prevalence rates in East Asian countries. The objective of this study was to describe the refractive status in children and adolescents growing up in Germany. Material and Methods. Non-cycloplegic refractive status of children of the LIFE Child study in Leipzig, Germany, was measured by wavefront-based autorefraction in 1934 sub- jects (925 girls / 1009 boys), aged 3 to 16 years (mean = 9.05 ± 3.91). Myopia was defined as spherical equivalent refractive error (SE) ≤ -0.75 diopters (D), emmetropia as -0.75 D &gt; SE &lt; +0.75 D, hyperopia as SE ≥ +0.75 D and astigmatism as cylinder ≤ -0.75 D. Anisometropia was defined as a difference of ≥ 1.0 D in the SE between the two eyes. Results. Analysis revealed that refractive error became more myopic with older age (b = -0.08, p &lt; 0.001), with an observed prevalence of myopia of 27 % in 16-year-old children (4 % in 3-year-olds). The true prevalence of myopia might be lower as non-cycloplegic measurements might overestimate ref- ractive error in myopes and underestimate refractive error in hyperopes which in turn may overestimate the prevalence of myopia. The prevalence of anisometropia also increased with growing age (OR = 1.14, observed prevalence in 3- versus 16-year-olds = 2.3 % and 8.1 %, respectively). The prevalence of astigmatism was 11.8 %. Conclusion. Myopia prevalence in German children aged 3 to 16 years is around or even less than 10 %, taking into consideration that measurements were carried out without cycloplegia. Our results are comparable to other European paediatric studies. In comparison to East-Asian countries myopia prevalence, and thus the risk for eye diseases related to high myopia, is much lower in Germany. Keywords Myopia, prevalence, refraction, anisometropia, astigmatism, hyperopia

Socioeconomic mechanisms of myopia boom in China: a nationwide cross-sectional study

ObjectivesTo assess the association between socioeconomic development and the myopia boom in China.DesignNationwide cross-sectional study.SettingWe used data from the China Family Panel Study (CFPS 2010), and the Chinese National Survey...

Choroidal Thickness and Correlations with Intraocular Pressure and Spherical Equivalent in Young Myopic Eyes without Maculopathy

Background: Refractive error is one of the causes of visual impairment worldwide, among which myopia is the most common. Myopia is prevalent worldwide, particularly in East and Southeast Asia, which have myopia prevalence rates of approximately 80-90% and high myopia prevalence rates of 10-20% in young adults. High myopia is closely related to a variety of pathological changes and a higher risk of blinding complication. Purpose: To identify the distribution of choroidal thickness (CT) and to determine whether there are associations between subfoveal choroidal thickness (SFCT) and intraocular pressure (IOP) and spherical equivalent (SE) in young healthy myopes without maculopathy. Methods: A total of 116 young subjects without maculopathy were recruited in this study and underwent comprehensive ophthalmic examinations. Enhanced depth imaging spectral domain optical coherence tomography was performed for CT measurement and assessment. SFCT, as well as CT at 3 mm nasal, temporal, superior and inferior to fovea were measured. Univariable linear regression analysis and Multiple regression analysis were used to study the correlation between SFCT and spherical equivalent (SE) as well as IOP. To assess the CT at each location and explore it’s associated factors. Results: The SFCT of high myopes was notably thinner (197.00±35.21 µm) compared with mild myopes (287.05±68.31 µm) and moderate myopes (251.13±64.40µm). For all three groups, CT at 3 mm nasal was the thinnest (195.21±52.43µm, 168.43±59.24µm, 129.56±30.97µm, respectively.) Univariable linear regression analysis indicated that SFCT decreased by 15.49 µm per diopter in myopic refractive change (P <0.001, R2 = 0.146) and decreased by 17.87 µm per 1mmHg increase inintraocular pressure (IOP) (P < 0.001, R2 = 0.440). Multiple regression analysis indicated that there were significantly correlations between SFCT and spherical equivalent (SE) as well as IOP in mild myopes and moderate myopes, but not in high myopes. Conclusions: A significant difference of the CT distribution was found in the centre region among myopes. However, nasal choroid thinning was the most obvious in all myopia groups. SFCT was significantly correlated with IOP and SE in the myopic population. However, the same correlation was not observed in young highly myopic eyes.

Prevalence of myopia and vision impairment in school students in Eastern China

BackgroundPrevention of myopia has become a public health priority in China. This study is to investigate the prevalence of myopia and vision impairment, and their associated factors in school students in eastern China.MethodIn this cross-sectional school-based study of 4801 students from 16 schools ranging from kindergarten to high school, students underwent refraction using non-cycloplegic autorefractor and visual acuity testing using logMAR chart with tumbling E. Myopia was defined as spherical equivalent (SPHE) ≤ − 0.5 diopter (D) and uncorrected visual acuity (UCVA) 20/25 or worse. High myopia was defined as SPHE ≤ − 6.0 D and UCVA 20/25 or worse. Vision impairment was defined as UCVA 20/40 or worse. Logistic regression models were used to determine factors associated with myopia and vision impairment.ResultsAmong 4801 children (55% male) with mean age (standard deviation) 12.3 (3.8) years, 3030 (63.1, 95% CI: 61.7–64.5%) had myopia, 452 (9.4, 95% CI: 8.6–10.3%) had high myopia, and 2644 (55.1, 95% CI, 53.7–56.5%) had vision impairment. The prevalence rate of myopia increased with grade in a non-linear manner, 12% in kindergarten, 32% in grade 2, 69% in grade 5, and approximately 90% by grade 10 or above. The prevalence rate of high myopia was relatively low in grade 4 or below (< 1.5%), 4–7% in grade 5 to 7, 13–15% in grade 8–9, and > 20% in grade 10 to 12. The prevalence rate of vision impairment was 4% in kindergarten, 37% in elementary school, 77% in middle school and 87% in high school students. Higher grade (p < 0.0001), female (p < 0.0001) and higher school workload (p = 0.007) were independently associated with higher prevalence rates of myopia and vision impairment, while higher grade (p < 0.0001) and higher school workload (p < 0.0001) were independently associated with higher prevalence of high myopia.ConclusionPrevalence of myopia and vision impairment was high among Chinese school students and increased with grade in a non-linear manner, reaching alarming high in high school students accompanied by high prevalence of high myopia. Increasing study burden on school students at younger age plays an important role on the higher prevalence rate of myopia and vision impairment.

The epidemiology of myopia in school children worldwide.

AbstractPurposeBoth genetic and environmental factors play a role in the increasing prevalence of myopia. This modern rise mirrors the trend of children spending a considerable amount of time reading, studying or—more recently—being glued to computer and smartphone screens. The aim of this study is to present an update on the current epidemiology and risk factors for myopia in school children in different countries around the world.MethodologyPubMed and Medline were searched for the following keywords: prevalence, incidence, myopia, refractive error, risk factors, children and visual impairment. English language articles published between Jan 1, 2013 and Nov 30, 2018 were included in the study. Studies were critically reviewed for study methodology and robustness of data. Seventy‐nine studies were included in the review.ResultsPrevalence remains higher in Asia (60%) compared with Europe (40%) using cycloplegic refraction examinations. Studies reporting on non‐cycloplegic measurements show exceptionally high myopia prevalence rates in school children in East Asia (70%–80%) compared with North America (42.2%). Low prevalence under 10% was described in African and South American children. New risk factors, apart from outdoor time and near work exposure, such as dim light, the use of LED lamps for homework, low sleeping hours, reading distance less than 25 cm and living in an urban environment were described in recent studies.ConclusionsThe high rates of myopia prevalence among school children, especially Asian populations, are strongly influenced by particular lifestyle habits. Increase in outdoor time remains the best strategy to prevent myopia onset. Additional epidemiological studies should be carried out on implementation of public health strategies to tackle and avoid myopia onset. High‐risk populations with high myopia prevalence might need a combined approach of increased outdoor time, changes in near distance activities in preschool children and treatment to control myopia progression.

Current Prevalence of Myopia and Association of Myopia With Environmental Factors Among Schoolchildren in Japan

Given the estimates of increasing prevalence of myopia, especially in Asia, it is important to determine the current prevalence of myopia among populations of schoolchildren in Japan. To investigate the current prevalence rate of myopia and the association between environmental factors and myopia in Japanese schoolchildren. This cross-sectional study assessed 1478 participants, including 726 elementary school students and 752 junior high school students, at 2 schools in Tokyo, Japan, who underwent eye examinations from April 1 to May 31, 2017, that included measurement of the refractive errors by autorefractometry with noncycloplegic refraction and ocular biometric factors. After excluding those who had been treated with atropine or orthokeratology (n = 11), had a history of eye disease (n = 2), had no parental consent (n = 41), and were absent (n = 8), 1416 schoolchildren were analyzed. The primary outcome was the prevalence of myopia and high myopia. Secondary outcomes were environmental factors that were associated with myopia. A total of 1416 schoolchildren (mean [SD] age, 10.8 [2.7] years; 792 [55.9%] male) were studied. The prevalence rates of myopia (spherical equivalent ≤-0.5 diopters [D]) were 76.5% (95% CI, 73.4%-79.7%) among the elementary school students and 94.9% (95% CI, 93.3%-96.5%) among the junior high school students. The prevalence rates of high myopia (spherical equivalent ≤-6.0 D) were 4.0% (95% CI, 2.5%-5.4%) among the elementary school students and 11.3% (95% CI, 8.8%-13.7%) among the junior high school students. The prevalence rates of high myopia classified based on axial length of 26.0 mm or longer were 1.2% (95% CI, 0.4%-2.0%) among elementary school students and 15.2% (95% CI, 12.5%-17.8%) among junior high school students. Multiple regression analysis showed that higher-order aberrations and dry eye disease were associated with refractive error in elementary school students (spherical aberration: β = 6.152; 95% CI, 3.161-9.143; P < .001; dry eye disease: β = -0.626; 95% CI, -1.189 to -0.063; P = .03) and with axial length in junior high school students (spherical-like aberration: β = 26.546; 95% CI, 18.708-34.385; P < .001; dry eye disease: β = 0.354; 95% CI, 0.131-0.578; P < .002). Although the use of noncycloplegic autorefraction with a cutoff of -0.50 D could lead to overestimation of results, these findings suggest that the current prevalence rates of myopia among elementary and junior high school students in Asia are high, especially if the results from these 2 schools are generalizable to all schoolchildren in Japan and Asia.

Risk Factors for Incident Myopia among Teenaged Students of the Experimental Class of the Air Force in China.

Background In recent decades, the prevalence rate of myopia has markedly increased, especially among teenagers. Our purpose was to determine the incidence of myopia and identify the related risk factors among schoolchildren in the experimental classes of the Air Force in China. Methods In May 2015, this 3-year prospective cohort study enrolled 522 boys (age, 14–16 years) attending grade 10 in 16 high schools in 15 cities in China. Cycloplegic refraction was examined using retinoscopy in both eyes at the baseline and follow-up (3 years). A detailed questionnaire was completed by the students at the 3-year follow-up and included questions on parental myopia and on the total time spent doing near work and outdoor activities each week. Results The incidence of myopia at the 3-year follow-up was 27.01% (141/522, 95% confidence interval (CI): 23.38% to 30.98%). The refractive change was −0.46 D (95% CI: −0.49 to −0.42 D). More hyperopic or less myopic baseline refraction, outdoor activity time per week ≥14 h (odds ratio (OR) = 0.464, 95% CI: 0.227 to 0.950), and reading/writing distance ≥ 30 cm (OR = 0.505, 95% CI: 0.270 to 0.944) were significant protective factors against incident myopia. Near-work time ≥28 h per week was a significant risk factor (OR = 2.579, 95% CI: 1.314 to 5.061). Parental myopia, age at the start of primary school, continuous reading/writing for ≥1 h, sleep duration per week <49 h, and one or more dietary biases were not significant risk factors (P > 0.05). Conclusion A more hyperopic baseline refraction, more time spent outdoors, and longer writing/reading distance were protected against myopia onset, while more near-work time was a risk factor.