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Indian Journal of Ophthalmology Aug 2022Myopia or short-sightedness is an emerging pandemic affecting more than 50% population in South-Asian countries. It is associated with several sight-threatening... (Review)
Review
Myopia or short-sightedness is an emerging pandemic affecting more than 50% population in South-Asian countries. It is associated with several sight-threatening complications, such as retinal detachment and choroidal neovascularization, leading to an increased burden of visual impairment and blindness. The pathophysiology of myopia involves a complex interplay of numerous environmental and genetic factors leading to progressive axial elongation. Environmental factors such as decreased outdoor activity, reduced exposure to ambient light, strenuous near work, and role of family history of myopia have been implicated with increased prevalence of this refractive error. While multiple clinical trials have been undertaken to devise appropriate treatment strategies and target the modifiable risk factors, there is no single treatment modality with ideal results; therefore, formulating a comprehensive approach is required to control the myopia epidemic. This review article summarizes the epidemiology, dynamic concepts of pathophysiology, and evolution of the treatment modalities for myopia such as pharmacological (atropine and other agents) and optical methods (spectacles, contact lenses, and orthokeratology).
Topics: Atropine; Contact Lenses; Disease Progression; Eyeglasses; Humans; Myopia
PubMed: 35918919
DOI: 10.4103/ijo.IJO_2098_21 -
Acta Ophthalmologica May 2018To generate percentile curves of axial length (AL) for European children, which can be used to estimate the risk of myopia in adulthood.
PURPOSE
To generate percentile curves of axial length (AL) for European children, which can be used to estimate the risk of myopia in adulthood.
METHODS
A total of 12 386 participants from the population-based studies Generation R (Dutch children measured at both 6 and 9 years of age; N = 6934), the Avon Longitudinal Study of Parents and Children (ALSPAC) (British children 15 years of age; N = 2495) and the Rotterdam Study III (RS-III) (Dutch adults 57 years of age; N = 2957) contributed to this study. Axial length (AL) and corneal curvature data were available for all participants; objective cycloplegic refractive error was available only for the Dutch participants. We calculated a percentile score for each Dutch child at 6 and 9 years of age.
RESULTS
Mean (SD) AL was 22.36 (0.75) mm at 6 years, 23.10 (0.84) mm at 9 years, 23.41 (0.86) mm at 15 years and 23.67 (1.26) at adulthood. Axial length (AL) differences after the age of 15 occurred only in the upper 50%, with the highest difference within the 95th percentile and above. A total of 354 children showed accelerated axial growth and increased by more than 10 percentiles from age 6 to 9 years; 162 of these children (45.8%) were myopic at 9 years of age, compared to 4.8% (85/1781) for the children whose AL did not increase by more than 10 percentiles.
CONCLUSION
This study provides normative values for AL that can be used to monitor eye growth in European children. These results can help clinicians detect excessive eye growth at an early age, thereby facilitating decision-making with respect to interventions for preventing and/or controlling myopia.
Topics: Adolescent; Adult; Axial Length, Eye; Child; Disease Progression; Europe; Female; Follow-Up Studies; Humans; Male; Middle Aged; Myopia; Prevalence; Prospective Studies; Refraction, Ocular; Young Adult
PubMed: 29265742
DOI: 10.1111/aos.13603 -
JAMA Ophthalmology Oct 2021Pathologic myopia due to an excessive increase of axial length is associated with severe visual impairments. Systematic analyses to determine the rate of and the risk...
IMPORTANCE
Pathologic myopia due to an excessive increase of axial length is associated with severe visual impairments. Systematic analyses to determine the rate of and the risk factors associated with the axial elongation in adults with high myopia based on long-term follow-up of a large population are needed.
OBJECTIVE
To determine the risk factors associated with axial elongation in adults with high myopia.
DESIGN, SETTING, AND PARTICIPANTS
This cohort study used the medical records of 43 201 patient visits in a single-hospital database that were collected from January 3, 2011, to December 28, 2018. A total of 15 745 medical records with the patients' sex, best-corrected visual acuity (BCVA), axial length, type of myopic maculopathy, and the presence or absence of choroidal neovascularization (CNV) were reviewed. Data were analyzed from April 3, 2019, to August 5, 2020.
MAIN OUTCOMES AND MEASURES
Changes in the axial length at each examination were calculated. The significance of the associations between the annual increase of the axial length and age, sex, baseline axial length, types of myopic maculopathy, and a history of CNV was determined. Generalized linear mixed models were used to evaluate the strength of the risk factors associated with an increase of the axial length in high myopia.
RESULTS
Among 1877 patients with 9161 visits included in the analysis, the mean (SD) age was 62.10 (12.92) years, and 1357 (72.30%) were women. The mean (SD) axial length was 29.66 (2.20) mm with a mean (SD) growth rate of 0.05 (0.24) mm/y. Among the 9161 visits, 7096 eyes (77.46%) had myopic maculopathy and 2477 eyes (27.04%) had CNV. The odds ratio for inducing a severe elongation of the axial length was 1.46 (95% CI, 1.38-1.55) for female sex, 0.44 (95% CI, 0.35-0.56) to 0.63 (95% CI, 13 0.50-0.78) for older than 40 years, 1.33 (95% CI, 1.15-1.54) for BCVA of less than 20/400, 1.67 (95% CI, 1.54-1.81) to 2.67 (95% CI, 2.46-2.88) for baseline axial length of 28.15 mm or greater, 1.06 (95% CI, 0.96-1.17) to 1.39 (95% CI, 1.24-1.55) for the presence of maculopathy, and 1.37 (95% CI, 1.29-1.47) for prior CNV.
CONCLUSIONS AND RELEVANCE
This cohort study found continuing axial elongation in adults with high myopia. The risk factors for elongation do not appear to be modifiable, so prevention of myopia may be the best approach to reduce the incidence of pathologic myopia and its complications in the future.
Topics: Adult; Choroidal Neovascularization; Cohort Studies; Female; Humans; Macular Degeneration; Male; Middle Aged; Myopia; Myopia, Degenerative; Retinal Diseases; Retrospective Studies; Risk Factors; Vision Disorders; Visual Acuity
PubMed: 34436537
DOI: 10.1001/jamaophthalmol.2021.3303 -
Clinical & Experimental Optometry Mar 2017
Topics: Accommodation, Ocular; Biomedical Research; Emmetropia; Humans; Myopia; Optometry; Refraction, Ocular
PubMed: 28273683
DOI: 10.1111/cxo.12531 -
Clinical & Experimental Optometry Nov 2015Myopia is a significant public health problem worldwide, particularly in East Asian countries. The increasing prevalence of myopia poses a huge socio-economic burden and... (Review)
Review
Myopia is a significant public health problem worldwide, particularly in East Asian countries. The increasing prevalence of myopia poses a huge socio-economic burden and progressive high myopia can lead to sight-threatening ocular complications. Hence, the prevention of early-onset myopia progressing to pathological high myopia is important. Recent epidemiological studies suggest that increased outdoor time is an important modifiable environmental factor that protects young children from myopia. This protective effect may be due to high light intensity outdoors, the chromaticity of daylight or increased vitamin D levels. This review summarises the possible underlying biological mechanisms for the protective association between time outdoors and myopia, including the potential role of nicotinic acetylcholine receptors in refractive error development. Recent evidence for the role of other environmental risk factors such as near work, birth seasons, parental smoking and birth order are also summarised.
Topics: Adolescent; Child; Global Health; Humans; Myopia; Prevalence; Refraction, Ocular; Risk Assessment; Risk Factors; Surveys and Questionnaires
PubMed: 26497977
DOI: 10.1111/cxo.12346 -
Ophthalmology Nov 2022To evaluate the efficacy of time outdoors per school day over 2 years on myopia onset and shift. (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
To evaluate the efficacy of time outdoors per school day over 2 years on myopia onset and shift.
DESIGN
A prospective, cluster-randomized, examiner-masked, 3-arm trial.
PARTICIPANTS
A total of 6295 students aged 6 to 9 years from 24 primary schools in Shanghai, China, stratified and randomized by school in a 1:1:1 ratio to control (n = 2037), test I (n = 2329), or test II (n = 1929) group.
METHODS
An additional 40 or 80 minutes of outdoor time was allocated to each school day for test I and II groups. Children in the control group continued their habitual outdoor time. Objective monitoring of outdoor and indoor time and light intensity each day was measured with a wrist-worn wearable during the second-year follow-up.
MAIN OUTCOME MEASURES
The 2-year cumulative incidence of myopia (defined as cycloplegic spherical equivalent [SE] of ≤-0.5 diopters [D] in the right eye) among the students without myopia at baseline and changes in SE and axial length (AL) after 2 years.
RESULTS
The unadjusted 2-year cumulative incidence of myopia was 24.9%, 20.6%, and 23.8% for control, test I, and II groups, respectively. The adjusted incidence decreased by 16% (incidence risk ratio [IRR], 0.84; 95% confidence interval [CI], 0.72-0.99; P = 0.035) in test I and 11% (IRR = 0.89; 95% CI, 0.79-0.99; P = 0.041) in test II when compared with the control group. The test groups showed less myopic shift and axial elongation compared with the control group (test I: -0.84 D and 0.55 mm, test II: -0.91 D and 0.57 mm, control: -1.04 D and 0.65 mm). There was no significant difference in the adjusted incidence of myopia and myopic shift between the 2 test groups. The test groups had similar outdoor time and light intensity (test I: 127 ± 30 minutes/day and 3557 ± 970 lux/minute; test II: 127 ± 26 minutes/day and 3662 ± 803 lux/minute) but significantly more outdoor time and higher light intensity compared with the control group (106 ± 27 minutes/day and 2984 ± 806 lux/minute). Daily outdoor time of 120 to 150 minutes at 5000 lux/minutes or cumulative outdoor light intensity of 600 000 to 750 000 lux significantly reduced the IRR by 15%~ 24%.
CONCLUSIONS
Increasing outdoor time reduced the risk of myopia onset and myopic shifts, especially in nonmyopic children. The protective effect of outdoor time was related to the duration of exposure and light intensity. The dose-response effect between test I and test II was not observed probably because of insufficient outdoor time achieved in the test groups, which suggests that proper monitoring on the compliance on outdoor intervention is critical if one wants to see the protective effect.
Topics: Child; Humans; Prospective Studies; Mydriatics; China; Myopia; Refraction, Ocular; Schools
PubMed: 35779695
DOI: 10.1016/j.ophtha.2022.06.024 -
The British Journal of Ophthalmology Jul 2016The aim of this review was to quantify the global variation in childhood myopia prevalence over time taking account of demographic and study design factors. A systematic... (Meta-Analysis)
Meta-Analysis Review
Global variations and time trends in the prevalence of childhood myopia, a systematic review and quantitative meta-analysis: implications for aetiology and early prevention.
The aim of this review was to quantify the global variation in childhood myopia prevalence over time taking account of demographic and study design factors. A systematic review identified population-based surveys with estimates of childhood myopia prevalence published by February 2015. Multilevel binomial logistic regression of log odds of myopia was used to examine the association with age, gender, urban versus rural setting and survey year, among populations of different ethnic origins, adjusting for study design factors. 143 published articles (42 countries, 374 349 subjects aged 1-18 years, 74 847 myopia cases) were included. Increase in myopia prevalence with age varied by ethnicity. East Asians showed the highest prevalence, reaching 69% (95% credible intervals (CrI) 61% to 77%) at 15 years of age (86% among Singaporean-Chinese). Blacks in Africa had the lowest prevalence; 5.5% at 15 years (95% CrI 3% to 9%). Time trends in myopia prevalence over the last decade were small in whites, increased by 23% in East Asians, with a weaker increase among South Asians. Children from urban environments have 2.6 times the odds of myopia compared with those from rural environments. In whites and East Asians sex differences emerge at about 9 years of age; by late adolescence girls are twice as likely as boys to be myopic. Marked ethnic differences in age-specific prevalence of myopia exist. Rapid increases in myopia prevalence over time, particularly in East Asians, combined with a universally higher risk of myopia in urban settings, suggest that environmental factors play an important role in myopia development, which may offer scope for prevention.
Topics: Child; Ethnicity; Female; Global Health; Humans; Male; Myopia; Prevalence; Rural Population; Surveys and Questionnaires; Time Factors
PubMed: 26802174
DOI: 10.1136/bjophthalmol-2015-307724 -
Ugeskrift For Laeger Nov 2023The prevalence of myopia is estimated to be 2.6 billion people worldwide and the percentage of individuals with sight-threatening high myopia (≤ -6 diopters) is... (Review)
Review
The prevalence of myopia is estimated to be 2.6 billion people worldwide and the percentage of individuals with sight-threatening high myopia (≤ -6 diopters) is increasing. Myopia is primarily caused by excessive axial elongation of the eyeball, and treatment modalities attempt to reduce this progression. While increased outdoor time is known to delay myopia onset, new pharmacological and optical interventions aim to reduce myopia progression. This review finds that these promising interventions are expected to significantly decrease the future prevalence of sight-threatening high myopia.
Topics: Child; Humans; Adolescent; Disease Progression; Myopia; Prevalence
PubMed: 38018731
DOI: No ID Found -
American Journal of Ophthalmology Mar 2021To review the impact of increased digital device usage arising from lockdown measures instituted during the COVID-19 pandemic on myopia and to make recommendations for...
PURPOSE
To review the impact of increased digital device usage arising from lockdown measures instituted during the COVID-19 pandemic on myopia and to make recommendations for mitigating potential detrimental effects on myopia control.
DESIGN
Perspective.
METHODS
We reviewed studies focused on digital device usage, near work, and outdoor time in relation to myopia onset and progression. Public health policies on myopia control, recommendations on screen time, and information pertaining to the impact of COVID-19 on increased digital device use were presented. Recommendations to minimize the impact of the pandemic on myopia onset and progression in children were made.
RESULTS
Increased digital screen time, near work, and limited outdoor activities were found to be associated with the onset and progression of myopia, and could potentially be aggravated during and beyond the COVID-19 pandemic outbreak period. While school closures may be short-lived, increased access to, adoption of, and dependence on digital devices could have a long-term negative impact on childhood development. Raising awareness among parents, children, and government agencies is key to mitigating myopigenic behaviors that may become entrenched during this period.
CONCLUSION
While it is important to adopt critical measures to slow or halt the spread of COVID-19, close collaboration between parents, schools, and ministries is necessary to assess and mitigate the long-term collateral impact of COVID-19 on myopia control policies.
Topics: Adolescent; Adolescent Behavior; COVID-19; Child; Child Behavior; Child, Preschool; Computing Methodologies; Female; Humans; Male; Myopia; Practice Guidelines as Topic; Quarantine; Risk Factors; SARS-CoV-2; Screen Time; Social Media
PubMed: 32738229
DOI: 10.1016/j.ajo.2020.07.034 -
EBioMedicine Jul 2020Myopia is a good model for understanding the interaction between genetics and environmental stimuli. Here we dissect the biological processes affecting myopia...
BACKGROUND
Myopia is a good model for understanding the interaction between genetics and environmental stimuli. Here we dissect the biological processes affecting myopia progression.
METHODS
Human Genetic Analyses: (1) gene set analysis (GSA) of new genome wide association study (GWAS) data for 593 individuals with high myopia (refraction ≤ -6 diopters [D]); (2) over-representation analysis (ORA) of 196 genes with de novo mutations, identified by whole genome sequencing of 45 high-myopia trio families, and (3) ORA of 284 previously reported myopia risk genes. Contributions of the enriched signaling pathways in mediating the genetic and environmental interactions during myopia development were investigated in vivo and in vitro.
RESULTS
All three genetic analyses showed significant enrichment of four KEGG signaling pathways, including amphetamine addiction, extracellular matrix (ECM) receptor interaction, neuroactive ligand-receptor interaction, and regulation of actin cytoskeleton pathways. In individuals with extremely high myopia (refraction ≤ -10 D), the GSA of GWAS data revealed significant enrichment of the HIF-1α signaling pathway. Using human scleral fibroblasts, silencing the key nodal genes within protein-protein interaction networks for the enriched pathways antagonized the hypoxia-induced increase in myofibroblast transdifferentiation. In mice, scleral HIF-1α downregulation led to hyperopia, whereas upregulation resulted in myopia. In human subjects, near work, a risk factor for myopia, significantly decreased choroidal blood perfusion, which might cause scleral hypoxia.
INTERPRETATION
Our study implicated the HIF-1α signaling pathway in promoting human myopia through mediating interactions between genetic and environmental factors.
FUNDING
National Natural Science Foundation of China grants; Natural Science Foundation of Zhejiang Province.
Topics: Animals; Disease Models, Animal; Female; Gene-Environment Interaction; Genetic Predisposition to Disease; Genome-Wide Association Study; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Mice; Myopia; Sclera; Signal Transduction
PubMed: 32652319
DOI: 10.1016/j.ebiom.2020.102878