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The Influence of Study Habits on Myopia in Jewish Teenagers

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Abstract

The prevalence and degree of myopia were measured in 870 teenagers, males and females. We found a statistically significant higher prevalence and degree of myopia in a group of 193 Orthodox Jewish male students who differed from the rest in their study habits. Orthodox schooling is characterized by sustained near vision and frequent changes in accommodation due to the swaying habit during study and the variety of print size. A possible myopic effect of this unique visual demand is postulated.

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... 16,18,19 However, evidence regarding the roles of these factors is equivocal. 11,20,21 The Israeli Jewish male population provides a unique opportunity to study the contributions of genetic, environmental, and behavioral factors in the etiology of myopia owing to known differences in myopia prevalence among different groups and diverse behaviors, 22,23 combined with the genetic homogeneity of Israeli Jews. The Jewish people share genetic homogeneity because of their unique history. ...
... 25 By taking advantage of this naturally occurring homogenetic population, the impact of genetics is minimized, and focus can be placed on behavioral differences in various subgroups. A large population-based survey of 17-year-old Israeli Jewish boys demonstrated that ultra-Orthodox and religious boys have a higher prevalence of myopia (82.2 and 50.3%, respectively) compared with secular boys, with a prevalence (29.7%) similar to the global average. 1 This divergent rate of myopia in different populations of Israeli boys has been reported in several studies 1,23,26 and is thought to be a result of the study habits of Jewish boys rather than genetic factors. ...
... Previous studies have shown that ultra-Orthodox males in Israel are significantly more myopic than religious or secular males. 1,23,26 The authors hypothesized that the diverse educational systems contributed to the different rates of myopia, most likely because of near-work demands of the various systems. However, this has not yet been tested in a systematic manner. ...
Article
Significance: Evidence supporting the contributions of near work in myopia is equivocal. Findings from this pilot study suggest that a high prevalence of myopia in ultra-Orthodox boys may be attributed to intense near work at school and learning to read in preschool at an early age. Purpose: This study aimed to assess factors that may influence myopia in three groups of Jewish boys with different educational demands. Methods: Healthy ultra-Orthodox, religious, and secular Jewish boys (n = 36) aged 8 to 12 years participated. Refractive status, education, time spent reading and writing, and electronic device use were assessed using a questionnaire, and time outdoors and physical activity were assessed objectively using an Actiwatch. Data were analyzed with χ2 and Kruskal-Wallis tests with Bonferroni post hoc comparisons. Results: Ultra-Orthodox (n = 14) and religious (n = 13) children had greater myopia prevalence compared with secular children (n = 9; P = .01), despite no differences in parental myopia. Actigraph data showed that there were no differences in activity (P = .52) or time spent outdoors (P = .48) between groups. Ultra-Orthodox children learned to read at a younger age and spent more hours at school (P < .001 for both). All groups engaged in a similar amount of near work while not in school (P = .52). However, ultra-Orthodox boys had less electronic device use than did religious (P = .007) and secular children (P < .001). Conclusions: This pilot study demonstrates that ultra-Orthodox, religious, and secular children have distinct educational demands but similar time outdoors, physical activity, and near work while not in school. The findings suggest that near work at school and/or learning to read in preschool at an early age may contribute to previously reported differences in refractive error between groups. However, conclusions should be confirmed in a larger sample size.
... Their sustained near work is characterized by increased accommodative effort, accompanied by rocking movements back and forth to increase their concentration. There is emphasis on reading texts with varying font sizes, which may be as small as one millimetre in height [10]. Most of the curriculum is also characterized by intensive reading of small printed religious texts in class, and by few extracurricular activities or outdoor programs [11]. ...
... The prevalence of myopia in young Orthodox males was found to be around 72.5-81.3% [10,12] On the other hand, in China, the incidence of myopia among students is among the highest of any cultural or ethnic group, and it affects both genders equality [14]. It may emphasis the importance of the overall balance of near work and time outdoors as well as the different curricular activities between the genders in the Ultra Orthodox community. ...
... Male and female students are separated in ultra-Orthodox schools, and they have different curricula and study conditions with the boys having longer study hours viewing smaller print. Zylbermann et al. showed that the prevalence of myopia in Orthodox teenager's males was more than twice the percentage in females' in Israel with a higher mean of the myopia [10]. In our cohort we also found higher percentage of myopia in fathers compared to mothers. ...
Article
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Background The ultra-Orthodox Jewish community has a unique lifestyle including minimal outdoor activity and intense, prolonged nearby work, beginning at a very young age. Their prevalence of myopia is extremely high. This paper provides a unique insight into the attitudes of this community towards myopia. Methods Ultra-Orthodox Jewish parents of children who came to the pediatric ophthalmology clinic in one tertiary care and two community centers in ultra-Orthodox-oriented cities were given a questionnaire. Demographic information, along with myopia prevalence in the family, was gathered. In addition, their attitudes and common knowledge regarding myopia were investigated. Results 161 questioners were collected, mostly completed by mothers (n = 110, 68%). The average number of children per family was 6 (range 1–16). In 148 families (92%) at least one of the parents has myopia. The average parent refraction was − 4.5 diopters (range − 0.5 to 15 diopters). Out of 935 children, 410 (44%) wore glasses. Twelve parents (7%) believe that myopia is a disease and 94 (58%) reported that they are concerned because their child wears glasses. Twenty-four (15%) believe that glasses are a sign of a high education level. Regarding treating myopia progression, 144 (89%) think that myopia progression should be treated, but only 36 (22%) are aware of the available treatments for it. Conclusion This study examines an insular community with a very high incidence of myopia. In this community most parents think that myopia progression should be treated but most of them are unaware of the currently available treatments.
... The genetic pool has changed little over the past few decades, but the changes in the environmental factors may be responsible for the rapid increase in the prevalence of myopia (26). It seems that school myopia is multifactorial, strongly associated with intensive educational pressure and limited outdoor activities (27). In terms of educational level, there was a high prevalence of myopia in boys attending Orthodox schools in Israel compared with their peers attending secular schools (27). ...
... It seems that school myopia is multifactorial, strongly associated with intensive educational pressure and limited outdoor activities (27). In terms of educational level, there was a high prevalence of myopia in boys attending Orthodox schools in Israel compared with their peers attending secular schools (27). The mechanism involved is unclear; however, nearwork requires more accommodation which may stimulate eye growth. ...
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Background Myopia is one of the most common causes of vision impairment in children and adults and has become a public health priority with its growing prevalence worldwide. This study aims to identify and evaluate the global trends in myopia research of the past century and visualize the frontiers using bibliometric analysis. Methods The literature search was conducted on the Web of Science for myopia studies published between 1900 and 2020. Retrieved publications were analyzed in-depth by the annual publication number, prolific countries and institutions, core author and journal, and the number of citations through descriptive statistics. Collaboration networks and keywords burst were visualized by VOSviewer and CiteSpace. Myopia citation network was visualized using CitNetExplorer. Results In total, 11,172 publications on myopia were retrieved from 1900 to 2020, with most published by the United States. Saw SM, from the National University of Singapore, contributed the most publications and citations. Investigative Ophthalmology & Visual Science was the journal with highest number of citations. Journal of Cataract and Refractive Surgery with the maximum number of publications. The top 10 cited papers mainly focused on the epidemiology of myopia. Previous research emphasized myopia-associated experimental animal models, while recent keywords include “SMILE” and “myopia control” with the stronger burst, indicating a shift of concern from etiology to therapy and coincided with the global increment of incidence. Document citation network was clustered into six groups: “prevalence and risk factors of myopia,” “surgical control of myopia,” “pathogenesis of myopia,” “optical interventions of myopia,” “myopia and glaucoma,” and “pathological myopia.” Conclusions Bibliometrics analysis in this study could help scholars comprehend global trends of myopia research frontiers better. Hundred years of myopia research were clustered into six groups, among which “prevalence and risk factors of myopia” and “surgical control of myopia” were the largest groups. With the increasing prevalence of myopia, interventions of myopia control are a potential research hotspot and pressing public health issue.
... 13 The very high prevalence of myopia seen in Israeli Jewish boys attending Orthodox or Ultra-Orthodox schools, compared with that in their sisters, or other children receiving more secular education, is also difficult to explain in genetic terms. 34,35 Again, it is possible to postulate that there is a sex-linked gene variant that predisposes to myopia segregating at a high frequency in Orthodox or Ultra-Orthodox Jewish communities in Israel, and indeed there are examples of rare, sex-linked forms of high myopia. 36 With modern molecular genetic techniques it would be relatively straightforward to identify such a gene variant should it exist; but to date there is no evidence that this is the case. ...
... 160 Similarly, the Liwan Eye Study reported that sex differences in older adults were marginal, 161 but in more recent cohorts in China, girls are more likely to be myopic than boys. 11,162 The extremely large difference in the prevalence of myopia in girls and boys in Orthodox Jewish communities in Israel, where the boys undergo very intensive education from an early age, shows this trend in reverse, 34,35 and contrasts with the similarity of boys and girls receiving more secular education. This variability does not suggest a direct biological link between sex and myopia, but rather suggests that the associations may be mediated by social factors, such as access to education for girls, which varies markedly between locations and has improved considerably in many places in recent decades. ...
Article
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Risk factor analysis provides an important basis for developing interventions for any condition. In the case of myopia, evidence for a large number of risk factors has been presented, but they have not been systematically tested for confounding. To be useful for designing preventive interventions, risk factor analysis ideally needs to be carried through to demonstration of a causal connection, with a defined mechanism. Statistical analysis is often complicated by covariation of variables, and demonstration of a causal relationship between a factor and myopia using Mendelian randomization or in a randomized clinical trial should be aimed for. When strict analysis of this kind is applied, associations between various measures of educational pressure and myopia are consistently observed. However, associations between more nearwork and more myopia are generally weak and inconsistent, but have been supported by meta-analysis. Associations between time outdoors and less myopia are stronger and more consistently observed, including by meta-analysis. Measurement of nearwork and time outdoors has traditionally been performed with questionnaires, but is increasingly being pursued with wearable objective devices. A causal link between increased years of education and more myopia has been confirmed by Mendelian randomization, whereas the protective effect of increased time outdoors from the development of myopia has been confirmed in randomized clinical trials. Other proposed risk factors need to be tested to see if they modulate these variables. The evidence linking increased screen time to myopia is weak and inconsistent, although limitations on screen time are increasingly under consideration as interventions to control the epidemic of myopia.
... Myopia has become an important public health issue worldwide, especially in Asian countries, and is a major cause of correctable visual impairment [1,2]. The increasing prevalence of myopia is thought to be linked to the environment, such as intensive education, more near work, and less time spent outdoors [3][4][5][6][7][8]. Several studies have reported that near work is a vital contributor to myopia [9,10], but the exact reasons why near work exacerbates myopia are not well understood. ...
... This has attracted the interest of many researchers, and they have tried to determine the possible mechanisms by which periods of prolonged near work could result in myopia. Different mechanisms have been found to be proposed, including accommodation error during near work (which means a lag in accommodation when the accommodation response is unable to meet the dioptric demand) and the small transient myopic far point shift immediately after long-term near work [3,11]. These two mechanisms are thought to be key factors in myopia progression. ...
Article
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Purpose To investigate the effects of reading with mobile phone versus text on accommodation accuracy and near work-induced transient myopia (NITM) and its subsequent decay during near reading in young adults with mild to moderate myopia. Methods The refractions of 31 young adults were measured with an open-field autorefractor (WAM-5500, Grand Seiko) for two reading tasks with a mobile phone and text at 33 cm. The mean age of the young adults was 24.35 ± 1.80 years. The baseline refractive aspects were determined clinically with full distance refractive correction in place. The initial NITM and its decay time and accommodative lag were assessed objectively immediately after binocularly viewing a mobile phone or text for 40 min. Results The mean ± standard deviation (SD) initial NITM magnitude was greater for reading with text (0.23 ± 0.26 D) than for reading with mobile phone (0.12 ± 0.17 D), but there was no significant difference between the two reading tasks ( p = 0.082). The decay time (median, first quartile, and third quartile) was 60 s (16, 154) and 70 s (32, 180) in the phone task and text task groups, respectively. There was also no significant difference in the decay time between the two reading types in general ( p = 0.294). The accommodative lags of text tasks and mobile phones tasks were equivalent (1.27 ± 0.52 D vs 1.31 ± 0.64 D, p = 0.792). Conclusion There were no significant differences in accommodative lags and the initial NITM and its decay time between reading with a mobile phone and text in young adults.
... First, most of the existing studies included in this systematic review were from Asia, which has higher prevalence rates of visual impairment. The myopia prevalence in East Asia was already reported to be high before the introduction of digital devices [53]. Previous studies indicated that myopia prevalence increased more rapidly in people with more years of education and intensive schooling without particular exposure to screen devices [54][55][56]. ...
... For example, a study conducted in Singapore found that myopia prevalence increased more rapidly among individuals who started elementary school after the 1980s [57]. Consistently, a study in Israel found that teenage boys who attended Orthodox schools had much higher rates of myopia than students from other schools who spent less time reading books in the 1990s [53]. Therefore, education and intensive schooling may have a large contribution to the increase in myopia prevalence [58]. ...
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BACKGROUND Smartphone overuse has been cited as a potentially modifiable risk factor that can result in visual impairment. However, reported associations between smartphone overuse and visual impairment have been inconsistent. OBJECTIVE The aim of this systematic review was to determine the association between smartphone overuse and visual impairment, including myopia, blurred vision, and poor vision, in children and young adults. METHODS We conducted a systematic search in the Cochrane Library, PubMed, EMBASE, Web of Science Core Collection, and ScienceDirect databases since the beginning of the databases up to June 2020. Fourteen eligible studies (10 cross-sectional studies and 4 controlled trials) were identified, which included a total of 27,110 subjects with a mean age ranging from 9.5 to 26.0 years. We used a random-effects model for meta-analysis of the 10 cross-sectional studies (26,962 subjects) and a fixed-effects model for meta-analysis of the 4 controlled trials (148 subjects) to combine odds ratios (ORs) and effect sizes (ES). The I <sup>2</sup> statistic was used to assess heterogeneity. RESULTS A pooled OR of 1.05 (95% CI 0.98-1.13, P =.16) was obtained from the cross-sectional studies, suggesting that smartphone overuse is not significantly associated with myopia, poor vision, or blurred vision; however, these visual impairments together were more apparent in children (OR 1.06, 95% CI 0.99-1.14, P =.09) than in young adults (OR 0.91, 95% CI 0.57-1.46 , P =.71). For the 4 controlled trials, the smartphone overuse groups showed worse visual function scores compared with the reduced-use groups. The pooled ES was 0.76 (95% CI 0.53-0.99), which was statistically significant ( P <.001). CONCLUSIONS Longer smartphone use may increase the likelihood of ocular symptoms, including myopia, asthenopia, and ocular surface disease, especially in children. Thus, regulating use time and restricting the prolonged use of smartphones may prevent ocular and visual symptoms. Further research on the patterns of use, with longer follow up on the longitudinal associations, will help to inform detailed guidelines and recommendations for smartphone use in children and young adults.
... First, most of the existing studies included in this systematic review were from Asia, which has higher prevalence rates of visual impairment. The myopia prevalence in East Asia was already reported to be high before the introduction of digital devices [53]. Previous studies indicated that myopia prevalence increased more rapidly in people with more years of education and intensive schooling without particular exposure to screen devices [54][55][56]. ...
... For example, a study conducted in Singapore found that myopia prevalence increased more rapidly among individuals who started elementary school after the 1980s [57]. Consistently, a study in Israel found that teenage boys who attended Orthodox schools had much higher rates of myopia than students from other schools who spent less time reading books in the 1990s [53]. Therefore, education and intensive schooling may have a large contribution to the increase in myopia prevalence [58]. ...
Article
Full-text available
Background Smartphone overuse has been cited as a potentially modifiable risk factor that can result in visual impairment. However, reported associations between smartphone overuse and visual impairment have been inconsistent. Objective The aim of this systematic review was to determine the association between smartphone overuse and visual impairment, including myopia, blurred vision, and poor vision, in children and young adults. Methods We conducted a systematic search in the Cochrane Library, PubMed, EMBASE, Web of Science Core Collection, and ScienceDirect databases since the beginning of the databases up to June 2020. Fourteen eligible studies (10 cross-sectional studies and 4 controlled trials) were identified, which included a total of 27,110 subjects with a mean age ranging from 9.5 to 26.0 years. We used a random-effects model for meta-analysis of the 10 cross-sectional studies (26,962 subjects) and a fixed-effects model for meta-analysis of the 4 controlled trials (148 subjects) to combine odds ratios (ORs) and effect sizes (ES). The I2 statistic was used to assess heterogeneity. ResultsA pooled OR of 1.05 (95% CI 0.98-1.13, P=.16) was obtained from the cross-sectional studies, suggesting that smartphone overuse is not significantly associated with myopia, poor vision, or blurred vision; however, these visual impairments together were more apparent in children (OR 1.06, 95% CI 0.99-1.14, P=.09) than in young adults (OR 0.91, 95% CI 0.57-1.46,P=.71). For the 4 controlled trials, the smartphone overuse groups showed worse visual function scores compared with the reduced-use groups. The pooled ES was 0.76 (95% CI 0.53-0.99), which was statistically significant (P
... Several researchers and clinicians have hypothesized that a child's visual environment is an important contributor to the development of myopia: in particular, an increase in near work and/or an increase in exposure to indoor lighting (Morgan et al., 2018;Read, Collins, & Vincent, 2014;Zylbermann, Landau, & Berson, 1993). The near-work hypothesis states that activities, such as viewing a mobile device at close range, forces the child to focus near (by increasing curvature of the crystalline lens) and that this effort promotes eye growth, which in turn produces myopia (Morgan et al., 2018;Zylbermann et al., 1993). ...
... Several researchers and clinicians have hypothesized that a child's visual environment is an important contributor to the development of myopia: in particular, an increase in near work and/or an increase in exposure to indoor lighting (Morgan et al., 2018;Read, Collins, & Vincent, 2014;Zylbermann, Landau, & Berson, 1993). The near-work hypothesis states that activities, such as viewing a mobile device at close range, forces the child to focus near (by increasing curvature of the crystalline lens) and that this effort promotes eye growth, which in turn produces myopia (Morgan et al., 2018;Zylbermann et al., 1993). ...
Article
The human eye changes focus—accommodates—to minimize blur in the retinal image. Previous work has shown that stimulation of nonfoveal retina can produce accommodative responses when no competing stimulus is presented to the fovea. In everyday situations it is very common for the fovea and other parts of the retina to be stimulated simultaneously. We examined this situation by asking how nonfoveal retina contributes to accommodation when the fovea is also stimulated. There were three experimental conditions. (a) Real change in which stimuli of different sizes, centered on the fovea, were presented at different optical distances. Accommodation was, as expected, robust because there was no conflicting stimulation of other parts of the retina. (b) Simulated change, no conflict in which stimuli of different sizes, again centered on the fovea, were presented at different simulated distances using rendered chromatic blur. Accommodation was robust in this condition because there was no conflict between the central and peripheral stimuli. (c) Simulated change, conflict in which a central disk (of different diameters) was presented along with an abutting peripheral annulus. The disk and annulus underwent opposite changes in simulated distance. Here we observed a surprisingly consistent effect of the peripheral annulus. For example, when the diameter of the central stimulus was 88 (thereby stimulating the fovea and parafovea), the abutting peripheral annulus had a significant effect on accommodation. We discuss how these results may help us understand other situations in which nonfixated targets affect the ability to focus on a fixated target. We also discuss potential implications for the development of myopia and for foveated rendering.
... For example, it would be unethical to offer differential educational opportunities to children in a randomly selected fashion, but social differences often lead to differential educational opportunities, and these can be highly informative, although they lack randomization. The high prevalence of myopia seen in Jewish males who received an intensive religious education, compared to their sisters who received a less intensive religious education, as well as boys and girls who received a less intensive secular education [78], provides rather compelling evidence of causality. In some cases, Mendelian randomization analysis can be used. ...
... Similarly, the Liwan Eye Study reported that sex differences in older adults were marginal [140], but in younger cohorts, girls were more likely to be myopic than boys [141]. The massive difference between the prevalence of myopia in girls and boys in Orthodox Jewish communities in Israel, where the boys undergo very intensive education from an early age, provides an extreme inverted example of this trend [78]. This variability does not suggest a direct biological link between sex and myopia, but rather suggests that the links may be mediated by social factors such as access to education for girls, which have changed considerably in many places in recent decades. ...
Chapter
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Myopia is often described as resulting from a complex set of interactions between genetic and environmental risk factors. Rare forms of strongly familial myopia account for myopia in around 1% of any population. “School myopia”, the most common form in most modern societies, is also influenced by genetic factors, but changes in environmental risk factors appear to be responsible for the major increases in the prevalence of myopia in some parts of East and Southeast Asia. Two major environmental risk factors have been identified—intensive schooling and limited time outdoors, with educational pressures high and time outdoors particularly limited in the parts of East and Southeast Asia afflicted by an epidemic of school myopia. Several other “independent” risk factors for myopia have been reported. The effects of many of these may be mediated by modulation of the two major risk factors, and in future studies on risk factors, mediation analysis needs to be used systematically. In the case of school myopia, we argue that there are two major environmental risk factors, with a limited role for genetic variation and minimal interactions. We propose a method for comparing the impact of identified genetic risk factors with the cumulative effects of environmental exposures. This suggests that genetic risk factors associated with more myopic refractions generally lead to myopia only when combined with exposures to environmental risk factors. The predominant role played by increased educational pressures and limited time outdoors suggests strategies for controlling the current epidemic of myopia by directly reducing educational pressures, perhaps by limiting homework and rote learning in the early school years, combined with increases in time spent outdoors in schools. Identification of distal environmental factors, such as early onset of competition for selective academic streams and schools, and the use of after-school tutorial classes also suggest strategies for reducing the current epidemic through changes at the school system level. When combined with clinical techniques for controlling the progression of myopia, these measures have the potential to markedly reduce the current high prevalence rates of both myopia and sight-threatening pathological high myopia.
... 23,24 Environmental factors that have been reported include little time spent outdoors, 25,26 extended near work, 27,28 season of birth, 29 maternal smoking during pregnancy, 30 birth order, 31 number of years of education, 24,32 and study habits. 33 The exact interplay between environmental factors leading to increase in the prevalence and severity of myopia remains a subject of intense research. 1,7,34,35 Large databases have been used in a broad range of ophthalmic research studies into disease surveillance, trends, causes, and outcomes. ...
... They are characterized by a higher prevalence and degree of myopia (in general and compared with females), probably because of a high abundance of myopia-related risk factors, including many hours of reading inside closed and dim rooms. 8,33,65 Fourth, participants who showed an uncorrected visual acuity score of 6/6 e1 were assumed to have a refractive error of 0 D, and therefore, some myopic participants may have been missed. However, uncorrected visual acuity assessment has been shown to be a sensitive method for detecting myopia. ...
Article
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Purpose: To determine the trends in prevalence of myopia in Israeli young adults over approximately a generation, as well as associated factors and variation in the impact of these factors on myopia prevalence in this region over time. Design: Retrospective, cross-sectional study. Participants: One hundred four thousand six hundred eighty-nine consecutive persons 16 to 19 years of age born between 1971 and 1994 who had not yet enlisted in the Israeli Army but had completed the medical profiling process. Methods: Using data collected at a north Israel recruitment center, the prevalence of myopia over time was estimated, and a polynomial regression analysis was performed to assess significance of nonlinear trends. Associations of demographic and socioeconomic factors with myopia were assessed, and trends over time were analyzed using a factorial logistic regression. Main outcome measures: The primary outcome measure was factors associated with the prevalence of myopia over time. The secondary outcome measure was a description of the change in prevalence of myopia over time. Results: The prevalence of myopia increased 1.284-fold over 24 years from 20.4% among participants born between 1971 and 1982 to 26.2% among participants born between 1983 and 1994. A quite similar increase was observed among males (from 17.9% to 22.7%, respectively) and females (from 23.9% to 30.8%, respectively). The factors found to be associated with myopia were as follows: more recent date of birth, female gender, more years of education, being the eldest child, non-Israeli ethnic origin, and urban residence. However, there were significant trends over time in the effects of some of these factors, most notably an attenuation of the difference between participants of different religions in the recent birth-years period. Most of these associations and trends were observed in both males and females separately, with some gender-specific variations. Immigrants from Ethiopia who were raised in Israel were highly more likely to demonstrate myopia than those who arrived at an older age. Conclusions: This study demonstrated an increase in the prevalence of myopia and the possible associations of urbanization- and higher education-related factors among several subpopulations and the risk for myopia developing.
... An association between educational systems and myopia has been identified in several studies in Singapore and Israel. 7,[16][17][18] The results from those studies showed that increased number of hours reading and better education were associated with myopia. In our study we J o u r n a l P r e -p r o o f found a much younger age of myopia onset in adults that attended full-day school in childhood compared with adults attending for only half-days (4 hours). ...
Article
Purpose To investigate the effect of tutorial classes and schooling schedule in childhood on age of myopia onset. Methods Refractive data for subjects ≥18 years of age were collected from 8 dispensing opticians or refractive ophthalmologists’ offices in Argentina. Age of myopia onset, spherical equivalent (SE), and risk factors were determined using questionnaires. Multiple linear regression models were applied to assess possible factors associated with age of myopia onset or final adult SE. Results A total of 274 adults (61.3% females) with myopia between −0.50 and −6.00 D were included. Mean age was 36.9 ± 14.5 years. The mean adult SE was −2.95 ± 1.45 D, and the mean age of myopia onset was 14.2 ± 5.4 years. Subjects that attended after-school tutorial classes (β = −2.23; P = 0.005) or a full day schedule in primary school (β = −1.07; P = 0.035) or that spent more time on near work (β = −0.70; P = 0.010) in childhood, had younger age of myopia onset. Conclusions In our study cohort, adults that had attended tutorial classes and/or full-day schooling during childhood had younger age of myopia onset.
... To analyze the relationship between tumor infiltrating lymphocyte subsets and survival of non-small cell lung cancer that tumor-infiltrating lymphocytes can defend against tumors [36]. Tumor-infiltrating T cells are lymphocytes dominated by T cells that exist locally in tumors and can inhibit tumor growth, representing the body's anti-tumor immune response [37]. ...
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Lung cancer is increasing every year and it has high morbidity and mortality. Antitumor immunotherapy is a new method for the treatment of lung cancer. Currently, tumor immunotherapy mainly includes classical immunotherapy and immune-targeted therapy To explore the influence of tumor T-lymphocyte (T-cell) infiltration in non-small-cell lung cancer (NSCLC) patients, 100 NSCLC patients diagnosed and treated in Changde Second People’s hospital were recruited. Patients were followed up for 3 years. The subjects were divided into a survival group (group S) and a death group (group D). The patient’s pathological tissue sections were made, and the degree of T-cell infiltration was counted by H&E (Hematoxylin and eosin) staining. The infiltration degree was graded, and the positive rate of T-cell subsets was calculated by immunohistochemical staining. The 3-year positive rate was 48%, with 48 cases in group S and 52 cases in group D. The positive rate of H&E staining of group S was 100%, including 0 cases of grade 0, 5 cases of grade 1 (10.42%), 16 cases of grade 2 (33.33%), and 27 cases of grade 3 (56.25%). The positive rate of group D was 86.54%, including 4 cases of grade 0 (8.89%), 10 cases of grade 1 (22.22%), 25 cases of grade 2 (55.56%), and 6 cases of grade 3 (13.33%). The total number of T-cell infiltrates in group S was much higher than that in group D ( P < 0.05 ). Immunohistochemical results showed that the mean positive rate of CD8+ T-cell infiltration was 72.1% in group S and 47.6% in group D, with a considerable difference ( P < 0.05 ). No remarkable difference was found in CD4+ and CD25+ ( P < 0.05 ). CD8+ + CD4+, CD8+/CD4+, CD25+/CD8+, CD25+/CD4+, and CD25+/(CD8+ + CD4+) positive rates were calculated, and the difference between group S and group D was substantial in CD8+ + CD4+ ( P < 0.05 ). The results showed that T cells infiltrated by tumors had an immunosuppressive effect on tumor cells.
... In Europe, an increased level of education has been related to increased levels of myopia [50]. The incidence of myopia among orthodox Jewish boys who spend a great deal of time reading religious texts at a near distance was higher than the incidence of myopia among girls in Jerusalem [54]. Thus, exposure to an intensive educational system at an early age is a potential risk factor [55,56]. ...
Article
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The relationship between vision and academic performance has been discussed for a long time, with special emphasis on visual factors associated with learning problems. The objective of this pilot study is to obtain an initial idea about the evolution and the impact of refractive errors on school-aged children. A visual examination was performed on 252 children between the ages of 6 and 11 years, which consisted of objective refraction, subjective refraction, and accommodative and binocular tests. No significant differences were observed regarding the refractive state when taking academic performance into account (p > 0.05). However, it was determined that academic performance was better among children with a negative spherical equivalent. Studies with a larger sample size must be conducted to verify the results that were attained in this present pilot study, and these must likewise look at possible ways in which strategies can be implemented in schools to reduce myopia progression.
... www.nature.com/scientificreports/ near work [15][16][17][18] have been proposed to explain the recent increasing trends of myopia in children, it would be interesting to know with a given set of confounding factors in an individual, how this drug behaves compared to placebo. There is a published literature 5 using atropine drops in one eye and the fellow eye as control, but the concentrations used were high and there is no study using 0.01% strength. ...
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We aimed to evaluate the efficacy and safety of low-dose atropine compared to placebo in the Indian population and also to study the impact of various modifiable and non-modifiable factors on myopia progression (MP) and drug efficacy (DE). It was a single-centre prospective placebo-controlled interventional study. 43 participants aged 6–16 years with progressive myopia received 0.01% atropine in the right eyes (treatment) and placebo in the left eyes (control) for 1-year. The main outcome measures were annual MP and axial length elongation (ALE) in treatment and control eyes and their percentage difference between two eyes (drug efficacy). Secondary outcome measures were the occurrence of any adverse events and the correlation of MP, ALE, and DE with various factors. 40 participants (80 eyes) completed the follow-up. After 1-year, MP was 0.25 D (IQR 0.13–0.44) and 0.69 D (IQR 0.50–1.0) (p < 0.001) in treatment and control respectively (63.89% reduction) with respective ALE of 0.14 mm (IQR 0.05–0.35) and 0.32 mm (IQR 0.19–0.46) (p < 0.001) (44.44% reduction). No adverse events were noted. Reduction in MP and ALE was statistically significant in all children irrespective of age-group, baseline MP, family history, screen-time, near and outdoor-time. The strongest determinants of annual MP were age (Treatment: r = − 0.418, p = 0.007; Control: r = − 0.452, p = 0.003) and baseline MP (Treatment: r = 0.64, p = 0.000; Control: r = 0.79, p = 0.000). Screen-time in control eyes was associated with greater ALE (r = 0.620, p = 0.042). DE was higher when outdoor time exceeded 2 h/day (p = 0.035) while the efficacy was lower with prolonged near activities (p = 0.03), baseline fast-progressors (p < 0.05) and history of parental myopia (p < 0.05). 0.01% atropine is effective and safe in retarding MP and ALE in Indian eyes.
... Historically, strong evidence of a causal role of studying and close work in increasing the prevalence of myopia came from Israeli boys attending Orthodox schools (with a reading load of 16 hours/day) who had a much higher prevalence of 80% compared to the 30% among girls attending the same school. Girls attending Orthodox schools had similar study habits (6 hours school day) as students attending secular schools, who also showed a myopia prevalence of 30% for both boys and girls [29][30][31]. Recently, two studies confirmed the causal association between educational attainment and myopia using the Mendelian randomization approach [32,33]. ...
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Aims To build a questionnaire-based myopia proxy and to validate the proxy by confirming its association with educational attainment and a Polygenic Risk Score (PRS) for myopia. Methods Data were collected between 2014 and 2017 from 88 646 Dutch adults from the LifeLines Cohort. First, we performed principal component analysis (PCA) to responses of five refraction-status questions. Second, we measured the refractive state in a subset of LifeLines participants (n=326) and performed logistic regression using myopia (mean spherical equivalent <−0.5 D) as a dependent variable and the principal components (PCs) as independent variables. We identified specificity, sensitivity and the classification threshold. Third, the classification equation was applied to the remaining LifeLines participants. The value of the proxy was then explored by calculating its association with educational attainment and a PRS of myopia. Results A total of 77 096 participants (58.1% women) were eligible for the PCA. The first two PCs had a specificity of 91.9% (95% CI 87.8% to 95.4%) and a sensitivity of 90.4% (95% CI 84.3% to 96.4%) for myopia. The area under the receiver operating characteristic curve was 95.0% (95% CI 92.2% to 97.8%). The age-standardised prevalence of proxy-inferred myopia was 33.8% (95% CI 33.4% to 34.3%). Compared with low education level, the ORs of proxy-inferred myopia were 1.66 (95% CI 1.58 to 1.74, p=5.94×10 ⁻⁹⁰ ) and 2.54 (95% CI 2.41 to 2.68, p=4.04×10 ⁻²⁷¹ ) for medium and high education levels, respectively. Similarly, individuals at the top 10% of PRS (vs lower 90%) had an OR of 2.18 (95% CI 1.98 to 2.41, p=6.57×10 ⁻⁵⁶ ) for proxy-inferred myopia, whereas those at the highest decile had an OR of 4.51 (95% CI 3.9 to 5.21, p=1.74×10 ⁻⁸⁹ ) when compared with the lowest decile. Conclusion Self-administered refractive error-related questions could be used as an effective tool to capture proxy-inferred myopic cases in a population-based setting.
... Previous studies in Israel compared the prevalence of myopia in Jewish children from different backgrounds, 19 in Jewish 17-year-old pre-army recruits, 21,32À34 and in Arab and Jewish first and eight grade children. 35,36 The results show that in Jewish pre-army recruits, women have a higher prevalence of myopia than men, 32À34 and ultra-Orthodox men have a higher prevalence of myopia than secular men. ...
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Purpose To determine the prevalence of refractive errors in Jewish and Arab college students in Israel and associations with ethnicity and sex. Methods In this retrospective cross-sectional study, first-year college students underwent non-cycloplegic autorefraction and answered a questionnaire to assess age, sex, and self-identified ethnicity. Spherical equivalent refractive error (SER) was calculated, and the prevalence of hyperopia (>+0.50 Diopter, D), emmetropia (>-0.50 to +0.50 D), myopia (≤-0.50D, low ≤-0.50 to >-3.0D, moderate <-3.0 to >-6.0D, high ≤-6.0D), and astigmatism (>0.50D) were determined. Groups were compared using Chi-square or Fisher test. Univariate and multivariate analyses were conducted to identify factors associated with refractive errors. Results Participants (n = 807) had a mean age of 22.1 ± 2.6 years (range: 17–30 years) and SER of -1.7 ± 2.2D (range: -13.3 to +5.7D). The prevalence and 95% confidence internal of myopia was 66.3% (63.0–69.6). Jewish students had a higher prevalence than Arab students for myopia (69.2% vs 60.3%), moderate (18.5% vs 12.2%) and high myopia (5.9% vs 1.9%) and astigmatism (51.4% vs 43.9%, p<0.05 for all), but not low myopia or hyperopia. Females had a higher prevalence of myopia than males (68.1% vs 58.7%, p<0.03). Jewish ethnicity was associated with myopia (OR=1.48, p = 0.01) and moderate myopia (OR=1.72, p = 0.01), and studying optometry was associated with moderate myopia (OR=1.63, p = 0.02). Sex and age were not associated with myopia. Conclusion Myopia prevalence in Israeli college students is high, showing associations with Jewish, but not Arab, ethnicity, suggesting that ethnic factors may play a role in the refractive differences between Arabs and Jews.
... Supplementary material associated with this article can be found in the online version at doi: 10 ...
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Why myopia develops, why it is reaching epidemic proportions and what is its cause are questions that puzzle many people. There is an answer to these questions and it is a simple one. This paper makes the connection between ametropic and in particular myopic development and theory to come with a summary of what we know about myopia and its governing equation. Key experiments, involving myopia and the effect of lenses in humans and animals have been done with unmistakable results. The observed effect of lenses implies a feedback mechanism. Feedback theory explains those results with mathematical precision. Disruption of emmetropization, is the mechanism behind ametropia and particularly myopia. Feedback theory for emmetropization was derived by observation of the input and output of the emmetropization feedback system in many patients. We show that it has the same equation as it is derived here independently from simple homeostasis principles. Classical observations and recent clinical studies have shown the association of many variables with myopia. They include near work, atropine, lenses, blur and outdoors versus indoors activities. We propose that human refractive development is controlled by homeostasis and based on that alone we derive the equation for the calculation of refraction for any patient and the effect of lenses. We provide software to calculate the refraction of any individual at any time. The editor of this journal makes the following statement: “This manuscript is intended for scientific discussion rather than clinical application. The present work does not intend to promote clinical under correction or no correction of myopia. Instead, clinicians should follow current clinical myopia management guidelines."
... Therefore, prevention of myopia progression needs to begin at younger ages. Although the etiology of the onset and progression of myopia remains unclarified, education as one of the environmental factors has been reported to be correlated with them [13][14][15], and school curriculum consisting of greater amounts of near work is associated with a higher rate of myopia [15][16][17]. ...
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This study aimed to investigate the influence of educational pressure on myopia. A less-intense school curriculum was introduced nationally in Japan beginning in 2012 based on a pressure-free education policy. In this retrospective observational study, a total of 1025 Japanese medical students of Asahikawa Medical University underwent measurements of the cycloplegic refractive error and axial length (AL), from 2011 to 2020. The spherical equivalent (SE) and AL were correlated significantly with the fiscal year of births (p = 0.004 and p = 0.034, respectively) only during enforcement of the system of high-pressure education. The SE and AL regression rates during the two educational approaches differed significantly (p = 0.004 and p = 0.037, respectively). The prevalence of high myopia was correlated significantly (p < 0.001) only during the system of high-pressure education. The regression of the prevalence rate of high myopia during the two education approaches differed significantly (p = 0.010). The progression rates of myopia and increased prevalence of high myopia were observed only during high-pressure education, suggesting that not only ophthalmologists but also educators and the government should work on together to control the progression of myopia.
... Likewise, Zylbermann found a similar result by matching orthodox Jews in Israel with a discordant number of years in education. [7] Increasing years of education, and its intensity, in east Asian countries like China is therefore thought to explain the rise of myopia in these countries. [8] In 2013 the British Government raised the school leaving age from 16 to 17, and then to 18 in 2015. ...
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Introduction: In the past decade, the minimal school leaving age has been raised twice. Previous studies have found evidence for a link between this type of policy and myopia. We aim to use the 1972 raising of school leaving age to estimate the effect of the raising of school leaving age in 2013 and 2015. Methods: We use a segmented regression model to conduct an instrumental time series analyses of the effect of years of education on myopia using the 1972 raising of school leaving age. To recover the effect of a one-year change, we use the effect of the change on years of education and reflective error in an instrumental variables analysis. Results: We found evidence for a 0.60 (SE = 0.10) increase in years of education and, after adjusting for probability of having missing data and sex, a -0.14d (SE = 0.03) for refractive error. Instrumental variables analyse implies a -0.24 d/year (SE = 0.05) change in refractive error for each additional year in education. Conclusion: Our results triangulate the findings of pervious quasi-experimental methods on the effect of years of education on myopia and imply that each raising of school leaving age in the 2010s should be expected to a lead to -0.07 d/yr change in refractive error in the UK population.
... Singapore, Hong Kong, Taiwan), and intensive schooling, alongside with less opportunities for children to spend time outdoors even before the introduction of smart devices (Xiang et al. 2013;Ding et al. 2017;Sensaki et al. 2017). A study on Jewish boys with very high study loads, attending ultra-orthodox schools, showed that boys were more myopic than their sisters with lower academic load (Zylbermann et al. 1993), which provided evidence of a causal role for education (Morgan & Rose 2019). In Singapore, myopia prevalence increased from 30% to 50% in individuals that started elementary school from 1920 to 1965 (Sensaki et al. 2017). ...
Article
Purpose To examine the association between near work, screen time including TV and outdoor time with myopia in children from the Sunflower Myopia Asian Eye Epidemiology Consortium (AEEC). Methods We analysed AEEC cross-sectional data (12 241 children) on risk factors (near work, screen time including TV and outdoor time) and myopia of six population-based studies (China, Hong Kong and Singapore). Cycloplegic refraction and axial length (AL) measurements were included. Risk factors were determined using questionnaires. Data were pooled from each study, and multivariable regression analysis was performed to evaluate the associations between risks factors and myopia, spherical equivalent (SE) and AL. Results Among the included children, 52.1% were boys, 98.1% were Chinese and 69.7% lived in urban areas. Mean±standard deviation (SD) for age was 8.8 ± 2.9 years, for SE was −0.14 ± 1.8 D and for AL was 23.3 ± 1.1 mm. Myopia prevalence was 30.6%. In multivariate analysis, more reading and writing (OR = 1.17; 95% CI, 1.11–1.24), more total near work (OR = 1.05; 95% CI, 1.02–1.09) and less outdoor time (OR = 0.82, 95% CI, 0.75–0.88) were associated with myopia (p’s < 0.05). These factors were similarly associated with SE and AL (p’s < 0.05), except for total near work and AL (p = 0.15). Screen time including TV was not significantly associated with myopia (p = 0.49), SE (p = 0.49) or AL (p = 0.83). Conclusion In this study, increased reading and writing and decreased outdoor time were associated with myopia. Screen time may be a surrogate factor of near work or outdoor time, but further research is needed to assess its role as an independent risk factor for myopia.
... Excessive near work may influence the development and progression of myopia. 11,100,340 Close reading distance (20-25 cm) and continuous reading (>45 min), head tilt, closer nib-to-fingertip distance (which means greater head tilt) have been associated with greater odds of myopia progression. 158,[340][341][342] In a 23-year follow-up study of Pärssinen, myopic progression was highest among those whose reading posture in childhood was sitting and lowest among those who reported reading in suppine position. ...
Article
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The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.
... [8][9][10][11] A widely accepted hypothesis, supported by experimental studies of nonhuman primates, 12 argues that hyperopic defocus caused by insufficient accommodation (accommodative lag) stimulates anomalous axial elongation of the eye. 5,9,13 The high prevalence of myopia among populations engaged in extensive near vision tasks (e.g., schools engaged in additional, after-school studies 14 ; the air force academy 15 ; theological schools 16 ; and the almost universal presence of accommodative lags at near 17,18 ) is consistent with the hypothesis that chronic hyperopic defocus due to accommodative lag is a causal factor in myopia development in young humans. 19 Evidence from cross-sectional studies is contradictory; some report accommodative lags in myopic children to be larger, 20,21 whereas others report it to be the same 22,23 as those observed in emmetropic eyes. ...
Article
Significance: The prevalence of myopia and use of electronic displays by children has grown rapidly in recent years. We found that children viewing electronic displays, however, experience hyperopic defocus levels similar to those previously reported for other stimuli. Purpose: This study aimed to compare accommodative behavior of nonmyopic and myopic children viewing a computer screen or mobile phone. Methods: Accommodative behavior was examined in 11 nonmyopic and 8 myopic children (11.32 ± 2.90 and 14.13 ± 2.30 years, respectively; P = .04; refractions, +0.51 ± 0.51 and -2.54 ± 1.29, respectively) using an open-field autorefractor (Grand Seiko) at target vergences from -0.25 to -5.00 D. Different size (scaled or nonscaled) and type (text or movie) stimuli were presented on an LCD monitor (distant) or an iPhone (near), with subjects viewing monocularly or binocularly in an illuminated or dark room. Results: At the typical reading distances (20 and 33 cm), all 19 children exhibited some amount of accommodative lag. Stimulus type had little impact on accommodation. However, slightly but statistically significant lower slopes were observed (Bonferroni-corrected significance level of P ≤ .01) for low room lighting (0.96 vs. 0.91; t test, t = 3.88; P = .003), nonscaled targets (0.99 vs. 0.92; t test, t = 4.28; P = .001), and monocular viewing (0.99 vs. 0.90; t test, t = 4.0; P = .002) in the nonmyopic group only. When viewing nonscaled stimuli binocularly (natural viewing), the means and standard deviations of accommodative lags (averaged across room lights on and off, and text and movie) were generally larger for the nonmyopes at all distances and were largest at 33 cm (0.73 ± 0.18 D for the nonmyopes and 0.49 ± 0.23 for the myopes; t test, t = 2.62; P = .01). Conclusions: Generally small (≤0.50 D) amounts of hyperopic defocus are present in children binocularly viewing handheld electronic devices (nonmyopes slightly more than myopes). Modern electronic devices do not expose children to unusually high levels of hyperopic defocus.
... Bez et al. [17] has recently reported a 9.3-fold increased odds of having myopia among ultra-Orthodox Jewish students exposed to near-work activities from a very young age compared with age-matched secular students. Similarly, another study found significantly higher rates of myopia among Orthodox Jewish male students, emphasizing the effect that near-work activities have on the development of myopia [35]. This argument gains support from our finding that verbal intelligence tests, which require acquisition of linguistic skills mainly through reading, had stronger association with myopia than non-verbal intelligence tests. ...
Article
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Background: Myopia is a leading cause of visual impairment worldwide, and its increasing incidence is of public health concern. Cognitive function was associated with myopia among children, but evidence for adolescents is scarce. The purpose of this study was to determine whether myopia is associated with cognitive function, and which cognitive ability, verbal or non-verbal, is involved. Methods: We conducted a population-based cross-sectional study of 1,022,425 Israeli candidates for military service aged 16.5-18 years. Participants underwent a comprehensive battery of tests assessing verbal and non-verbal intelligence, which yields a summarized cognitive function score (CFS). In addition, subjective visual acuity examination followed by objective non-cycloplegic refraction was carried out for each participant. Association between myopia and cognitive function was evaluated by multivariable logistic regression models adjusted for gender, age, country of origin, socioeconomic status, years of education, body mass index, height and year of examination. Results: Compared to the intermediate CFS of the entire cohort, participants who had the highest CFS had 1.85-fold (95% CI, 1.81 to 1.89; P < .001) higher odds of having myopia and 2.73-fold (95% CI, 2.58 to 2.88; P < .001) higher odds of high myopia, while participants with the lowest CFS had 0.59-fold (95% CI, 0.57 to 0.61, P < .001) lower odds of having myopia. The verbal components of the cognitive function assessment had stronger associations with myopia than the non-verbal components (P < .001, for all). Conclusions: Cognitive function, especially verbal intelligence, is strongly and consistently associated with myopia among adolescents.
... Orthodox Jewish students who attended religious boy schools (Yeshivas) in Israel show the same pattern [50]. Those students had a myopia prevalence of 80% compared to boys and girls who attended secular schools and whose prevalence was less than 40% [58]. Most strikingly, orthodox Jewish students and Chinese students, both of whom adhere to the same rigid learning practice with lots of reading but little time spent outdoors under natural light, yield almost identical results when one plots the prevalence of myopia against refractive power [50]. ...
Article
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This review discusses the rapid rise of myopia among school-age children in East and Southeast Asia during the last 60 years. It describes the history, epidemiology, and presumed causes of myopia in Asia, but also in Europe and the United States. The recent myopia boom is attributed primarily to the educational pressure in Asian countries, which prompts children to read for long hours, often under poor lighting and on computer screens. This practice severely limits the time spent outdoors and reduces exposure to sunlight and far vision. As a consequence, the eyes grow longer and become myopic. In a breakthrough study in Taiwan, it has been found that by increasing the time spent outdoors, the incidence of new myopia cases was reduced to half when children were sent onto the schoolyard for at least 2 h daily. This protection is attributed to the light-induced retinal dopamine, which blocks the abnormal growth of the eyeball. Once myopia has set in, low-dose atropine and orthokeratology have shown positive results in slowing myopia progression. Also, prismatic bifocal lenses and specially designed multifocal soft contact lenses have recently been tested with promising results. Treatment, however, must be initiated early as the disease progresses once it has started, thereby enhancing the risk for severe visual impairment and ultimately blindness.
... Potentially tied to increased accommodative lags, closer near working distances may be another risk factor for myopia development and progression Two studies reported an association between near working distances (<30 cm) and myopia presence/severity (Hartwig et al. 2011, and Gwiazda (2011) found that progressive addition lens treatments for myopia control were more effective, albeit to a small degree, in children with habitual near working distances of less than 30 cm. These results are also consistent with the findings of Zylbermann et al. (1993) showing that males in Israeli religious schools who were required to spend significant time reading while rocking back and forth in relation to the text (davening) were at greater risk of myopia compared with females in religious schools or those attending secular schools. ...
Article
Refractive errors are the product of a mismatch between the axial length of the eye and its optical power, creating blurred vision. Uncorrected refractive errors are the second leading cause of worldwide blindness. One refractive error currently attracting significant scientific interest is myopia, mostly owing to the recent rise in its prevalence worldwide and associated ocular disease burden. This increase in myopia prevalence has also been rapid, suggesting environmental influences in addition to any genetic influences on eye growth. This review defines refractive errors, describes their prevalence, and presents evidence for the influence of genetic and environmental factors related to refractive error development.
... Similarly, it is possible that the association may reflect higher pollution in more population dense areas. 34 Adjusting for time outdoors and time spent reading [5][6][7][8][9] made no change to the geographical associations, suggesting that they were not driven by differences in these factors. It is possible that population density reflects a marker of other lifestyle traits and risk factors that are not captured by our covariates. ...
Article
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Purpose: Previous studies have demonstrated positive associations between myopia and environmental risk factors such as urbanization. However, these have failed to account for the clustering of individuals within geographical areas, opening analyses to theoretical and statistical limitations. We demonstrate how a multilevel modelling approach can provide a more nuanced understanding of the relationship between geography and myopia. We examined longitudinal associations between onset of myopia and urban/rural status or population density. Methods: Data were collected over 5 visits during an 8-year period for a UK cohort of 3,512 children. Associations between incident myopia (spherical equivalent ≤ −1.00 diopters) and both urban/rural status and population density were examined using discrete time multilevel hazard models which allow the partitioning of variance into different neighborhood and school areas. Results: There was evidence for an association between myopia and higher population density (Hazard Ratio = 1.14; 95% CI = 1.032 to 1.26) after adjustment for a range of risk factors. There was no strong evidence that urban/rural status was associated with incident myopia. Only a minor amount of variation in myopia was attributable to geographical areas (<2.2%), and this was not explained by rurality or population density. Conclusion: Our findings contrast with previous studies and raise the possibility that some of the results reported may have been driven by confounding bias whereby geographical differences in myopia are driven by lifestyle factors that are correlated with geographical setting.
... El orden de nacimiento ha sido reportado en algunos estudios como un factor de riesgo para desarrollar miopía 5,[37][38][39] , sin embargo, la asociación reportada es baja (OR <1.3) 5 , muy similar a la de nuestro estudio (1.33; IC 95%: 0.80-2.23), aunque en nuestro estudio esta diferencia no fue estadísticamente significativa. ...
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Background and Objective: Myopia has become a public health problem, so it is important to know the prevalence of myopia in different populations, like in medical students who are considered a risk group. Our objective was to know the prevalence of myopia in medical students of the University of Monterrey, as well as to study the associated risk factors. Methods: A prospective, cross-sectional and observational study was conducted between October and December 2016. Three hundred medical students were evaluated regarding the presence of refractive errors through auto-kerato/refractome- ter measurement and a questionnaire to analyze the presence of known risk factors for myopia. Results: One hundred ei- ghty-nine students (68.7%) had myopia in one eye, and 149 (54.2%) in both. From the factors evaluated, only two were statistically significant. One was that patients with myopia were older than those without it (21.60 ± 2.27 vs. 20.77 ± 2.61, respectively; p = 0.01), and the second one was history of need of visual correction in all siblings (29.1 vs. 17.4% respectively; p = 0.04). Reading time, computer use, exercise time, overweight/obesity, having parents or one sibling who needs visual correction were similar between groups. Conclusions: In this group of medical students, the prevalence of myopia based on a refraction without cycloplegia is higher compared to other demographic groups of the Americas, and the only associa- ted risk factors were age and need of visual correction in all siblings.
... The high prevalence of myopia among populations that spend a lot of time doing near vision tasks (school children, high school and college students, and those in religious seminaries) further support the hypothesis that hyperopic defocus (central or peripheral) generated by accommodative lags during near work could stimulate eye growth. [16][17][18] Technology's role Technological developments have occurred during the same general time period as the epidemic: ...
Article
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The article discusses about the current use of electronic devices and a possible link to increasing myopia prevalence.
... Una de las posibles razones de esto es que en nuestro estudio la prevalencia de miopía alta fue muy baja ya que sólo el 2.18% de los alumnos la presentaron, siendo este grupo de pacientes donde la prevalencia es mucho mayor en mujeres que en hombres (35). El orden de nacimiento ha sido reportado en algunos estudios como un factor de riesgo para desarrollar miopía (5,(37)(38)(39), sin embargo, la asociación reportada es baja (OR<1.3) (5) muy similar a la de nuestro estudio (1.33. ...
Article
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Antecedentes y objetivo: La miopía se ha convertido en un problema de salud pública, por lo que es importante conocer su prevalencia en diferentes grupos poblacionales, los estudiantes de medicina son considerados un grupo de riesgo. Nuestro objetivo fue conocer la prevalencia de miopía en los estudiantes de medicina de la Universidad de Monterrey, así como estudiar los factores de riesgo asociados. Métodos: Estudio prospectivo, transversal y observacional, realizado entre octubre y diciembre de 2016. Se evaluaron 300 estudiantes de medicina. La presencia de error refractivo se evaluó mediante un autoquerato refractómetro, y la presencia de factores de riesgo conocidos de miopía se analizó mediante un cuestionario. Resultados: 189 alumnos (68.7%) tuvieron miopía en algún ojo y 149 (54.2%), en ambos ojos. De los factores estudiados, solo en dos hubo una diferencia estadísticamente significativa: los pacientes con miopía tuvieron mayor edad que los que no la presentaron (21.60 ± 2.27 vs. 20.77 ± 2.61, respectivamente), con una p = 0.01, además del antecedente de todos los hermanos usuarios de lentes (29.1 vs. 17.4%, respectivamente), con una p = 0.04. Las horas de lectura, el uso de computadora, el tiempo de ejercicio, el sobrepeso/obesidad, el tener padres o algún hermano que utilizan lentes fueron similares en ambos grupos. Conclusiones: En este grupo de alumnos de medicina, la prevalencia de miopía basada en una refracción sin ciploplegia es más alta que en otros grupos étnicos del continente americano, y los únicos factores de riesgo asociados fueron la edad y el que todos los hermanos utilicen lentes.
... A greater magnitude of myopia has been observed among those attaining a higher level of education [10], indicating a huge increase in myopic refractive error associated with demanding learning activities related to academic level. The high prevalence of myopia among male Jewish students in an Orthodox school was attributed to prolonged daily near work with a variety of near target sizes [11]. The effect of environment on vision has been at the center of debate regarding myopia development, where various environmental factors including near work, academic activity, outdoor physical activity, dietary intake and occupation have been implicated [12]. ...
Article
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Purpose Near work, accommodative inaccuracy and ambient lighting conditions have all been implicated in the development of myopia. However, differences in accommodative responses with age and refractive error under different visual conditions remain unclear. This study explores differences in accommodative ability and refractive error with exposure to differing ambient illumination and visual demands in Malay schoolchildren and adults. Methods Sixty young adults (21–25 years) and 60 schoolchildren (8–12 years) were recruited. Accommodative lag and accommodative fluctuations at far (6 m) and near (25 cm) were measured using the Grand Seiko WAM-5500 open-field autorefractor. The effects of mesopic room illumination on accommodation were also investigated. Results Repeated-measures ANOVA indicated that accommodative lag at far and near differed significantly between schoolchildren and young adults [F(1.219, 35.354) = 11.857, p < 0.05]. Post hoc tests using the Bonferroni correction showed that at near, there was a greater lag in schoolchildren (0.486 ± 0.181 D) than young adults (0.259 ± 0.209 D, p < 0.05). Repeated-measures ANOVA also revealed that accommodative lag at near demands differed statistically between the non-myopic and myopic groups in young adults and schoolchildren [F(3.107, 31.431) = 12.187, p < 0.05]. Post hoc tests with Bonferroni correction showed that accommodative lag at near was significantly greater in myopic schoolchildren (0.655 ± 0.198 D) than in non-myopic schoolchildren (0.202 ± 0.141 D, p < 0.05) and myopic young adults (0.316 ± 0.172 D, p < 0.05), but no significant difference was found between myopic young adults (0.316 ± 0.172 D) and non-myopic young adults (0.242 ± 0.126 D, p > 0.05). Accommodative lag and fluctuations were greater under mesopic room conditions for all ages [all p < 0.05]. Conclusion Greater accommodative lag was found in myopes than in emmetropes, in schoolchildren than in adults, and under mesopic conditions than under photopic conditions. Accommodative fluctuations were greatest in myopes and in mesopic conditions. These results suggest that differences exist in the amount of blur experienced by myopes and non-myopes at different ages and under different lighting conditions.
... Zylbermann et al. [18] determined that Orthodox Jewish boys, who receive an intensive religious education, are much more myopic than their sisters and the rest of their age cohort who receive a more secular education. Probably, the high degree and prevalence of myopia observed in the Orthodox male group may be due to their heavy accommodative eye use attributed to their different study habits. ...
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Purpose: The aim of the paper was to study the role of gender in the progression of myopia among Polish schoolchildren. Materials and methods: 4875 children from elementary schools and high schools were examined (2470 boys, aged 6-16 years, mean age 11.0, SD = 2.6 and 2405 girls, aged 6-16 years, mean age 11.1, SD = 2.6). The examined students were Caucasian and resided in and around Szczecin, Poland. The examination included retinoscopy under cycloplegia. The refractive error readings were reported as spherical equivalent (SE). Myopia was defined as SE of at least -0.5 D. Data analysis was performed using the Mann-Whitney U test and 2-sided Fisher's exact test. p values of less than 0.05 were considered statistically significant. Results: It was found that the SE among Polish boys is similar to the SE among Polish girls before the age of 9 years. However, in older children, lower SE values and higher prevalence of myopia were found among girls than boys, both at 9-13 years range (0.45 ± 1.05 vs 0.55 ± 1.23 D, p=0.047 and 8.30% vs 5.71%, p=0.015, respectively) and at 13-16 years range (0.32 ± 1.14 vs 0.54 ± 1.08 D, p=0.0093 and 10.37% vs 5.96%, p=0.0050), respectively. Conclusions: Gender is associated with the prevalence of myopia among Polish schoolchildren ranging from 9 to 16 years of age.
... Multiple etiologies for myopia have been identified, namely genetic inheritance (He et al., 2008;Hornbeak & Young, 2009) and sustained, up close effort associated with extensive reading and computer use, both of which increase with educational advancement (Zylbermann et al., 1993). In fact, the elevated frequency of myopia in Asian nations has been linked to increased academic pressures and lifestyle habits that reduce outdoor time (Morgan et al., 2012). ...
Article
This case study examined the hypothesis that longer outdoor time results in normal vision and refractive status, using unique genetically informative kinships. The participants were the members of 29-year-old doubly exchanged monozygotic male twin pairs from Bogotá, Colombia, in South America. Comprehensive ophthalmological examinations, including uncorrected and corrected visual acuity, refraction and keratometry, and visual life history interviews were undertaken; all examinations were conducted by two ophthalmologists blind to the hypothesis, relatedness, and rearing status of the four participants. Normal uncorrected vision and refractive status were present in the two rural-raised, unrelated brothers, relative to their urban-raised counterparts. Uncorrected visual acuities were 20/160 and 20/200 for the city-raised twins and 20/20 and 20/30 for the country-raised twins. Premature birth, low birth weight, computer use, and reading time could not explain these differences. It was concluded that time spent outdoors appears to be a significant factor in the development of myopia, reinforcing extant findings via a novel experimental approach.
... Another study of 870 teenagers reported a much higher prevalence of myopia among Orthodox male teenagers than among non-Orthodox teenagers (81.3% vs 27.4%). 28 One study examined 917 Israeli students in the third grade and found that male students from ultra-Orthodox schools had the highest rate of reduced unaided vision (72.5%) compared with male students from secular schools (27.3%), male students from Orthodox schools (59.3%), and female students from all 3 groups. 29 There are several differences between our study and previous works. ...
Article
Importance A substantial portion of the public is diagnosed with myopia, which increases the risk of potential sight-threatening complications. The association between study style and the development of myopia is unclear. Objective To analyze the association between studying in different educational systems and the prevalence and severity of myopia among Jewish male adolescents in Israel. Design, Setting, and Participants A nationwide, population-based study was conducted of 22 823 male candidates for military service in Israel aged 17 to 18 years attending the military draft board in 2013 who underwent a medical examination and a visual acuity assessment. Statistical analysis was performed from January 1 to March 31, 2018. Exposures The participants studied in 1 of 3 Israeli educational systems: secular, Orthodox, or ultra-Orthodox. The ultra-Orthodox system and, to a lesser extent, the Orthodox system involve intensive reading starting in early childhood compared with the secular system. Main Outcomes and Measures The odds ratio (OR) for the association between educational system and the prevalence and severity of myopia. Results Among the 22 823 participants (mean [SD] age, 17.7 [0.6] years), there was a higher proportion of adolescents in the ultra-Orthodox educational system with myopia (1871 of 2276 [82.2%]) compared with adolescents in the Orthodox educational system (1604 of 3189 [50.3%]) and those in the secular educational system (5155 of 17 358 [29.7%]). Compared with adolescents in the secular educational system, those in the Orthodox educational system were more likely to have myopia (OR, 2.3; 95% CI, 2.1-2.5; P < .001), as were those in the ultra-Orthodox educational system (OR, 9.3; 95% CI, 8.2-10.7; P < .001), after adjustment for age, country of origin, socioeconomic status, years of education, and body mass index. The multivariable adjusted OR for high myopia (refractive error of at least −6.0 diopters) was 4.6 (95% CI, 3.8-5.5; P < .001) for adolescents in the Orthodox educational system and 38.5 (95% CI, 30.7-48.2; P < .001) for adolescents in the ultra-Orthodox educational system compared with adolescents in the secular educational system. Conclusions and Relevance This study provides evidence of the independent association between educational systems and the prevalence and severity of myopia. Male adolescents in the ultra-Orthodox educational system have higher odds of having myopia and high myopia. These findings suggest that study styles that involve intensive reading and other near-work activities (those done at a short working distance) play a role in the development of myopia and warrant consideration of prevention strategies.
... The beam diameter of the RangeLife is narrow enough such that it was able to detect hand held devices, books, and computer monitors. These characteristics are ideal for assessing near viewing behaviors that have been linked to refractive error, including the duration and frequency of near work 16,44 , distance of reading material 38 , and other reading habits 45 . ...
Article
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Evidence regarding the role of near work in myopia is conflicting. We developed the RangeLife, a device for continuous, objective measurement of working distance. Four devices were built, calibrated, and validated. Then, adult subjects wore the device on weekdays and weekend days, while simultaneously wearing an actigraph device for objective measurements of light exposure and activity. Subjects maintained an activity log and answered a visual activity questionnaire. RangeLife data were downloaded and binned into 0.10 m intervals. Objective diopter hours (dh), a weighted measure of near work, were calculated. Diopter hours for all subjects were significantly higher on weekdays (14.73 ± 4.67 dh) compared to weekends (11.90 ± 4.84 dh, p = 0.05). 94 ± 1.85% of near and intermediate viewing distances were recorded when the subjects were exposed to mesopic and indoor photopic light levels (<1000 lux), and 80.03 ± 2.11% during periods of sedentary physical activity (<320 counts per minute). Subjective reports of time viewing near and intermediate distances significantly overestimated objective measures (p = 0.002). The RangeLife was shown to provide reliable measures of viewing distance, and can be further utilized to understand potential influences of viewing behaviors on refractive error.
Article
Objectives: The aim of the study was to identify the prevalence and risk factors of myopia and high myopia in students from primary school and junior high school in Shandong. Methods: A total of 35,614 subjects completed the visual acuity test, refraction error measurement, and questionnaire in 2019. The visual acuity test was performed using the standard logarithmic visual acuity chart and the refractive error was measured by an automatic refractometer without cycloplegia. Results: The average age was 12.38 ± 1.78 years, with 18,501 boys and 17,113 girls. The overall prevalence of myopia and high myopia was 68.02% and 5.90%, respectively, and reached up to 85.54% and 13.13% for the grade 9 students. The risk factors included girls, parental myopic history, time spent doing homework, and less sleep time. Performing eye exercise was significantly associated with a lower risk of myopia. Use of mobile devices and reading while lying down were only related to myopia, not high myopia. Conclusion: The prevalence of myopia and high myopia is at a high level. In addition to genetic factors, continuous close work and a lack of sleep was an important factor associated with children myopia and high myopia.
Article
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In 2018, a consortium of government bodies in China led by the Ministry of Education released the Comprehensive Plan to Prevent Nearsightedness among Children and Teenagers (CPPNCT), aiming to reduce the incidence of myopia and control myopic progression in China. Recommendations span from home-based to school-based interventions, including time outdoors, physical activity, light exposure, near-work activity, screen time, Chinese eye exercises, diet and sleep. To date, the levels of evidence for this suite of interventions have not been thoroughly investigated. This review has summarised the evidence of the interventions recommended by the CPPNCT in myopia prevention and control. Thus, the following statements are supposed by the evidence: (1) Increasing time outdoors and reducing near-work time are effective in lowering incident myopia in school-aged children. (2) All interventions have a limited effect on myopia progression. Ongoing research may lead to a better understanding of the underlying mechanisms of myopia development, the interaction of different interventions and recommendations, confounding variables and their true effect on myopia prevention, and the identification of those most likely to respond to specific interventions. This field may also benefit from longer-term studies of the various interventions or strategies covered within this review article, to better understand the persistence of treatment effects over time and explore more novel approaches to myopia control.
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Purpose: To model juvenile-onset myopia progression as a function of race/ethnicity, age, sex, parental history of myopia, and time spent reading or in outdoor/sports activity. Methods: Subjects were 594 children in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study with at least three study visits: one visit with a spherical equivalent (SPHEQ) less myopic/more hyperopic than -0.75 diopter (D), the first visit with a SPHEQ of -0.75 D or more myopia (onset visit), and another after myopia onset. Myopia progression from the time of onset was modeled using cubic models as a function of age, race/ethnicity, and other covariates. Results: Younger children had faster progression of myopia; for example, the model-estimated 3-year progression in an Asian American child was -1.93 D when onset was at age 7 years compared with -1.43 D when onset was at age 10 years. Annual progression for girls was 0.093 D faster than for boys. Asian American children experienced statistically significantly faster myopia progression compared with Hispanic (estimated 3-year difference of -0.46 D), Black children (-0.88 D), and Native American children (-0.48 D), but with similar progression compared with White children (-0.19 D). Parental history of myopia, time spent reading, and time spent in outdoor/sports activity were not statistically significant factors in multivariate models. Conclusions: Younger age, female sex, and racial/ethnic group were the factors associated with faster myopic progression. This multivariate model can facilitate the planning of clinical trials for myopia control interventions by informing the prediction of myopia progression rates.
Chapter
Highly myopic eyes may have shape distortion where there is a local deviation in curvature of the posterior portion of the eye as compared with the surrounding eye wall. When these distortions are manifested by an outpouching of the eye with associated uveal tissue, they are known as a staphyloma. Localized expansion of the choroid, retinal pigment epithelium, and retina may lead to a variety of stereotypical pathologies that have been recognized in high myopes for nearly two centuries. The history of staphyloma research, concepts of staphyloma formation, and hypotheses of staphyloma formation are presented. Special problems in highly myopic eyes attributed to staphylomas are discussed.
Article
I review the key findings and our current knowledge of the cause of myopia, making the connections among the reliable observations on myopia development and theory to arrive at a summary of what we know about myopia, the proposed prevailing theory, and applicable action. Myopia is reaching epidemic proportions. It is estimated that half of the world's population will be myopic by 2050 unless new strategies to fight myopia are developed. Our high-level mathematical description of myopia is translated into clinical applications involving effective treatment and prevention. A regulating mechanism controlling the refraction of the eye is intimately related to myopia. The approach at hand is to review our knowledge about emmetropization, connecting myopia and emmetropization feedback theory to unveil the cause of myopia. Many observations discussed here test the validity of feedback theory positively. The cause of human myopia fits perfectly with the idea that emmetropization. In particular, its feedback theory implementation is the controlling mechanism behind myopia. They include near work, atropine, lenses, defocus, and outdoor versus indoor activities. The key findings in myopia research point the same way: myopia is the result of corrective lenses interfering with emmetropization. We have enough knowledge to answer the question of whether myopia can be reversed or prevented. There is no need to have mathematical skills to apply theory to real cases. It is enough to know the predictions of the feedback theory of emmetropization.
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Purpose To investigate which baseline factors are predictive for success in controlling myopia progression in a group of children wearing MiSight Contact Lens (CLs). Methods Myopic patients (n = 41) fitted with MiSight CLs and followed up two years were included in this study. Bivariate analysis, a logistic regression analysis (LG) and a decision tree (DT) approach were used to screen for the factors influencing the success of the treatment. To assess the response, axial length (AL) changes were considered as main variable. Patients were classified based on a specific range of change of axial length at the end of each year of treatment as “responders” (R) (AL change <0.11 mm/per year) and “non-responders” (NR) (AL change ≥0.11 mm/per year). Results Of a total of forty-one Caucasian patients treated with MiSight CLs, 21 and 16 were considered responders in the first and the second year of follow-up, respectively. LG analysis showed that the only factor associated with smaller axial length growth was more time spent outdoors (p = 0.0079) in the first year of treatment. The decision tree analysis showed that in the responding group spending more than 3 and 4 h outdoors per week was associated with the best response in the first year and in the second year of treatment respectively. Conclusions The LR and the DT approach of this pilot study identifies time spent outdoors as a main factor in controlling axial eye growth in children treated with MiSight CLs.
Thesis
Cataract and age-related macular degeneration are important causes of blindness and visual impairment, and refractive error is highly prevalent and considerable time and expense is directed at its correction. Epidemiological studies have identified environmental risk factors for all these condition, while other studies have demonstrated familial aggregation. Twin studies, which compare the concordance of phenotypes in monozygotic and dizygotic twin pairs, can be used to elucidate the genetic epidemiology of eye disease - i.e. determine the relative importance of genes and environment. This thesis describes a classical twin study of 506 twin pairs (280 dizygotic and 226 monozygotic) with a mean age of 62 years. When they volunteered through national media campaigns, they were unaware of a potential eye study. Twins were comprehensively ascertained for refractive error using an autorefractor, and for cataract using subjective and objective grading techniques. Age-related macular degeneration was graded from stereoscopic macular photographs. Quantitative genetic model fitting, based on comparison of the covariance (or correlation) in the phenotype measurement between monozygotic and dizygotic twin pairs, determined the heritability, which is the ratio of genetic variance to total phenotypic variance. Mean scores were similar, but monozygotic twins were more concordant than dizygotic twins, for all phenotypes. This suggested genes are important in common eye diseases, even those age-related traits such as cataract, and was confirmed by modelling. The heritability of spherical equivalent was 84-86% and that of astigmatism 42-61%. The heritability of nuclear cataract was 48% and it was 53-58% for cortical cataract, depending on the grading system used. The heritability of early age-related maculopathy was 54%. Both astigmatism and cortical cataract appear to involve dominant inheritance. The heritability of age-related eye disease is substantial, and these results encourage identification of susceptibility genes through linkage and candidate gene studies, to further understand the mechanisms of disease.
Conference Paper
Emmetropization during early childhood and subsequent eye growth eventuating in myopia are determined by both inherited and experiential factors [1-3]. The high prevalence of myopia and its prominence as a public health problem emphasize the importance of gaining increased understanding of the visual signals that govern eye growth, which may point the way toward possible methods of control and prevention. This chapter summarizes the current state of knowledge of this refractive state, emphasizing research on human subjects. Extensive reviews of research using animal models to study mechanisms underlying myopia are found in Norton [4], Wildsoet [5], and Smith and Hung [6].
Article
Myopic children have larger ciliary muscles than non-myopic children, suggesting that the ciliary muscle may have an impact on or be affected by refractive error development. The guinea pig represents an attractive model organism for myopia development research. The purpose of the study was to investigate whether form deprivation-induced myopia in one or more strains of guinea pig causes thickening of the ciliary muscle as seen in human myopia. Thirty-nine guinea pigs were bred from in-house progenitors obtained from Cincinnati Children's Hospital (Cincinnati) and the United States Army (Strain 13). At 2-4 days of age the right eyes of animals were exposed to form deprivation for 7 days while the fellow eyes served as controls. Refractive error was determined with retinoscopy while vitreous chamber depth (VCD) and axial length (AL) were determined with A-scan ultrasound. Ciliary muscle characteristics (ciliary muscle length, cross-sectional area, volume, cell number, cell size, and smooth muscle actin concentration) were determined histologically with antibody labeling and analyzed according to whether the animal developed axial myopia (anisometropia > -2.00 D with VCD and/or AL differences > 0.1 mm) or was unresponsive. This analysis method yielded four groups with Group 1 having no induced myopia but with axial elongation (n = 11), Group 2 having myopia without vitreous or axial elongation (n = 8), Group 3 having myopia with either vitreous or axial elongation (n = 11), and Group 4 having myopia with both vitreous and axial elongation (n = 8). There were no post-treatment inter-ocular differences between strains or for the overall group of animals for any ciliary muscle variable; however, a higher response group number in multivariate ordinal regression was related to having a treated compared to fellow eye that had a lower smooth muscle actin concentration (p = 0.006), with a shorter ciliary muscle length (p = 0.042), and a less oblate eye shape (p = 0.010). Guinea pig ciliary muscle length and smooth muscle actin concentration were significantly less in the treated eyes of axially myopic animals suggesting that 7 days of form deprivation induced ciliary muscle cellular atrophy or inhibited ciliary muscle growth. Form deprivation myopia in the guinea pig does not result in the increase in ciliary muscle thickness associated with human juvenile and adult myopia.
Article
Background: The aim of this study was to investigate the prevalence of myopia in key (university-oriented) and non-key elementary schools in China using a traditional and a new criterion for myopia diagnosis in an epidemiological study. Methods: This school-based, cross-sectional study examined students from four key schools and seven non-key schools. Non-cycloplegic autorefraction and visual acuity (VA) were performed on each student. Myopia was defined as a spherical equivalent (SE) refractive error not better than -1.00 D. A questionnaire was also administered. Results: Of the 13,220 students examined, 6,546 (49.5 per cent) had myopia using the criterion of SE not better than -1.00 D. However, 2,246 (34.3 per cent) of these myopes had VA ≥ 0 logMAR in both eyes, indicating they were not functioning as myopes. Thus, a second myopia criterion was adopted: SE refractive error not better than -1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye. By this definition, only 32.5 per cent of the overall sample had myopia. Students in key schools had a higher prevalence of myopia than those in non-key schools (53.8 per cent versus 44.7 per cent) by the initial criterion. By the new criterion, the prevalence of myopia was 41.2 per cent versus 22.7 per cent. Myopia was equal in grade 1 of both school types, but accelerated faster in key schools, where there was a much higher prevalence of myopia by fourth grade, and continued up to 79.2 per cent prevalence by sixth grade based on SE refractive error not better than -1.00 D. Conclusion: Students in more competitive university-oriented elementary schools developed myopia much faster than those in regular schools, although they started with the same level of myopia. Since one-third of the 'myopes' had VA ≥ 0 logMAR in both eyes, they would not be prescribed a correction, or be clinically treated as myopes. A new criterion of SE refractive error not better than -1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye was tested. This criterion is more clinically appropriate and could be used in future epidemiological studies.
Article
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Two hundred and forty mildly myopic schoolchildren aged 9-11 years were randomly allocated to three treatment groups and the progression of myopia was followed-up for three years. The treatment groups were: (1) minus lenses with full correction for continuous use (the reference group), (2) minus lenses with full correction to be used for distant vision only, and (3) bifocal lenses with +1.75 D addition. Three-year refraction values were received from 237 children. The differences in the increases of the spherical equivalents were not statistically significant in the right eye, but in the left eye the change in the distant use group was significantly higher (-1.87 D) than in the continuous use group (-1.46 D) (p = 0.02, Student's t test). There were no differences between the groups in regard to school achievement, accidents, or satisfaction with glasses. In all three groups the more the daily close work done by the children the faster was the rate of myopic progression (right eye: r = 0.253, p = 0.0001, left eye: r = 0.267, p = 0.0001). Myopic progression did not correlate positively with accommodation, but the shorter the average reading distance of the follow-up time the faster was the myopic progression (right eye: r = 0.222, p = 0.0001, left eye: r = 0.255, p = 0.001). It seems that myopic progression is connected with much use of the eyes in reading and close work and with short reading distance but that progression cannot be reduced by diminishing accommodation with bifocals or by reading without spectacles.
Article
Many people have reduced unaided vision because of myopia, a spherical error of refraction. The biological theory of myopia views myopia as the result of genetically determined characteristics of eye tissues, whereas the use-abuse theory views myopia as the result of habitual use of the eye at a near focal length, near-work. The use-abuse theory implies that myopia is prevent able whereas the biological theory does not. Myopia varies over age, gender, race, ethnicity, level of education, social class and degree of urbanization. The explanation of the epidemiology of myopia in the use-abuse theory is that some types of people do more near-work than others. Using data from the Health Examination Survey of 12 to 17-year-olds conducted by the US Public Health Service from 1966–1970, this paper finds that the use-abuse theory can explain at least some of the variance of myopia and much of the socially patterned variance. This finding raises the possibility that at least some of the myopia extant in a population is preventable.
Article
Vision defects due to myopia typically appear during the school years. The comprehensive surveillance system of vision impairments in school children (ages 7 to 15 years) in the township of Kuopio, Finland (pop. 74 200) offers an opportunity to study the incidence of school myopia. In the school year 1980-81 out of 9635 school children 1383 (14%) had eye problems and were referred to the Community Health Center ophthalmologist (the author) for examination. Of the children who came for the first time to an eye examination 252 were found myopic. This gives an incidence of 2.6% per year. The incidence in different age groups as well as for boys and girls was caluclated. From the cumulative prevalences it was estimated that about 23% of the school children would be myopic at the age of 15 years.
Article
A study of 21 393 Icelanders over a 50-year-period showed the incidence of myopia to be 3.60% in 1935 and 20.47% in 1975. The paper discribes the details of this study showing the relative frequencies of different types of refraction in different age groups and with regard to sex.
Article
Eighteen families in which both parents had refractions within the range of +4·0 D to −4·0 D and axial lengths seen in emmetropia (22·3-26·0 mm) showed coefficients of correlation of the order 0·5 indicative of polygenic inheritance. Such coefficients were seen for axial length (0·407) and for the cornea (0·487), but not for the lens (which is known to be yoked to the axial length). No such coefficients were seen in 19 families in which one of the parents had axial length outside the emmetropic range (nine families with long axes and 10 with short axes).The pattern of polygenic inheritance for emmetropia (completely correlated optical components) and errors of refraction up to 4·0 D (inadequately correlated components: correlation ametropia) follows that seen in stature and other measurable characters. In contrast the high refractive errors with their abnormal axial lengths (component ametropia) are—like the extremes in stature—pathological anomalies with monofactorial inheritance.
Article
Physiologic myopia occurs as the result of a correlation failure of refraction components in the normal eye. Pathologic myopia is caused by excessive axial elongation that primarily involves the ora-equatorial area and the posterior pole. Peripheral fundus changes and posterior staphyloma formation are ophthalmoscopic evidences of this process. Heredity is the basic determinant of ocular refraction, but numerous agents produce both temporary and permanent myopias.
Article
Of the 745 available members of the population of Nain in Labrador 650 (87%) were screened for refractive errors and ocular disease. Refraction by retinoscopy was done in 553 and axial length measured by an optical method in 514. The results showed that the incidence of low degrees of myopia was higher in Inuit (Eskimos) and those of Mixed Inuit-Caucasian blood in the age groups 10 to 40 than in those over 40. 75% of the myopes came from 20 families in which myopia was present in 2 or more generations. Although there was no significant correlation between the refraction of parents and offspring, there were significant correlations between them for axial length. The axial lenths of the myopic eyes of the Inuit and Mixed populations were significantly longer than emmetropic and hypermetropic eyes. The younger memebers of the population were taller than their parents, and except in female Caucasians axial length showed a significant positive correlation with height. More myopes than emmetropes and hypermetropes achieved grade 8 or more in school. It is suggested that the increased incidence of myopia in the younger age groups might be due to environmental factors interfering with the process of emmetropisation in eyes with a genetic predisposition to myopia by virtue of inheriting a slightlt longer eye. Better nutrition resulting in an increase in stature may also have had some influence.
Article
Lid closure initiated early in life produces axial myopia in a variety of species. However, it is currently not known what aspects of the anomalous visual experience associated with lid closure disrupt the emmetropization process and cause abnormal ocular axial elongation. This study was designed to determine if a degradation in the quality of the spatial characteristics of the retinal image was sufficient to produce an experimental myopia. Optical rearing procedures were employed to defocus one eye of developing kittens, and retinoscopic and ultrasonic procedures were used to evaluate the effects of chronic optical defocus on the kitten's refractive status. Different defocusing lens designs and rearing protocols were included to evaluate variables that may have confounded previous investigations. The major finding is that early chronic optical defocus results in axial myopia. The prevalence and magnitude of the induced refractive errors were dependent on the magnitude of optical defocus, but they were not affected by the sign or form of the defocusing lens. The results demonstrated that the potential for a clear retinal image is important for regulating normal ocular growth and maintaining a near emmetropic refractive status.
Various environmental factors have been implicated in the etiology of myopia. An attempt was made quantitatively to estimate some such environmental factors, as based on the presence or absence of a family history of myopia. Age range was 10-21 years. The 200 subjects included in the study were further divided according to emmetropia/myopia. The factors studied in the four subgroups were amount of near work done per day, head posture and illumination level while doing near work, acute fevers, chronic illness, acute or recurrent diarrhea, nutritional status, and income levels. A correlation was found between myopia and near work, head posture and income levels.
Article
The onset of myopia typically occurs in childhood and increases during puberty. We studied the vision and refractive errors of 977 school children (ages 6 to 17 years) in 1983. Myopia in the group was extremely low; 97% had vision of 6/6, and 1.3% had myopia greater than 0.25D. Regression analysis revealed a change in mean refraction of -0.016D/year for males and -0.024D/year for females. There were no significant differences between males and females. These children engaged in about 8 hours of school work per day, and we conclude that genetic factors predominate over environmental factors in the determination of myopic refractive errors for this group.
Article
In order to assess the relative and interactive importance of genetic and environmental components on the development of myopia in Chinese school children aged from 10 to 15 years, a population-based sample of 361 same-sexed twin pairs recruited through stratified cluster sampling was studied. Zygosity of twin pairs was determined by Mendelian traits, red cell antigen systems, and continuous dermatoglyphic characteristics; while myopia was diagnosed by both objective and subjective techniques. Studying and reading habit was obtained from cotwins and their parents through a life style questionnaire. Age-sex-adjusted concordance rate derived from multiple regression equation was used in the analysis. Conventional comparison of intrapair concordance between monozygotic (MZ) and dizygotic (DZ) twins was used to assess the importance of a genetic component in the determining of myopia, and a significant genetic influence was observed. Environmental influence on myopia was evaluated through MZ cotwin method, and MZ cotwins with concordant studying and reading habits were significantly more concordant in myopia than those MZ cotwins with discordant habits. The possible effect of gene-environment interaction on myopia was explored, and concordance in myopia was found significantly associated with the interaction between zygosity and habit of studying and reading. These observations suggested that the impact of the environmental factor on the development of myopia may be influenced by genotype, and vice versa.
Article
The refraction of 12 street cats' eyes and of 11 caged cats was measured by retinoscopy, and the anteroposterior (axial) length of the eyeball was measured by ultrasound. While 87.5 per cent of eyes in street cats were found hypermetropic (average + 1.14 D), among cats caged for periods of 8.5-14.0 months under conditions of near vision. 68.2 per cent were myopic (average, -0.62 D). The anteroposterior length of the eyeball was practically equal in both groups (20.43 mm): it was also practically equal for myopic and hypermetropic eyes. The site of the refractive changes is discussed.
Article
Data from the 1971 to 1972 National Health and Nutrition Examination Survey were used to estimate myopia prevalence rates for persons in the United States between the ages of 12 and 54 years. When persons were classified by the refractive status of their right eye, 25% were myopic. Significantly lower prevalence rates were found for male subjects than for female subjects and for blacks than for whites. Myopia prevalence rose with family income and educational level. The importance of income and educational level may result from their association with near work, a factor that has been implicated in the pathogenesis of myopia.
Article
The relation of astigmatism and myopia was analyzed in 298 myopic children, ages birth to 10 years. The mean spherical equivalent, determined by cyclopentolate retinoscopy, for the entire group was--2.9 diopters and did not change significantly with age. However, in 3-year-old children and younger, myopia progressed in eyes with greater than or equal to 1 diopter of cylinder and tended to increase through age 8 years in those having greater than or equal to 3 diopters of cylinder. Also, astigmatic errors greater than or equal to 1 diopter, especially of oblique orientation, were associated with higher degrees of myopia than nonastigmatic errors. These data from myopic children suggest that uncorrected astigmatism during a period of visual immaturity influences the course of myopia. Thus, naturally occurring astigmatic errors, that are frequent among infants and young children, appear to have a role similar to the vision blurring perturbations that trigger the development of myopia in young animals. Ascertainment and full correction of these refractive errors in young children may be important in assuring the best possible vision.
This review of the literature is concerned with the relations between myopia and ethnic, behavioral, and physiological variables. A marked decrease in the number of studies is noted when current literature is compared with that of more than two decades past. It is concluded that cross-sectional studies of correlation must be replaced by longitudinal studies if we are to learn more concerning the cause(s) of myopia.
Article
Many people have reduced unaided vision because of myopia, a spherical error of refraction. The biological theory of myopia views myopia as the result of genetically determined characteristics of eye tissues, whereas the use-abuse theory views myopia as the result of habitual use of the eye at a near focal length, near-work. The use-abuse theory implies that myopia is preventable whereas the biological theory does not. Myopia varies over age, gender, race, ethnicity, level of education, social class and degree of urbanization. The explanation of the epidemiology of myopia in the use-abuse theory is that some types of people do more near-work than others. Using data from the Health Examination Survey of 12 to 17-year-olds conducted by the US Public Health Service from 1966--1970, this paper finds that the use-abuse theory can explain at least some of the variance of myopia and much of the socially patterned variance. This finding raises the possibility that at least some of the myopia extant in a population is preventable.