Association of Parental Myopia With Higher Risk of Myopia Among Multiethnic Children Before School Age

Identification of LRRC46 as a novel candidate gene for high myopia

High myopia (HM) is the primary cause of blindness, with the microstructural organization and composition of collagenous fibers in the cornea and sclera playing a crucial role in the biomechanical behavior of these tissues. In a previously reported myopic linkage region, MYP5 (17q21-22), a potential candidate gene, LRRC46 (c.C235T, p.Q79X), was identified in a large Han Chinese pedigree. LRRC46 is expressed in various eye tissues in humans and mice, including the retina, cornea, and sclera. In subsequent cell experiments, the mutation (c.C235T) decreased the expression of LRRC46 protein in human corneal epithelial cells (HCE-T). Further investigation revealed that Lrrc46-/- mice (KO) exhibited a classical myopia phenotype. The thickness of the cornea and sclera in KO mice became thinner and more pronounced with age, the activity of limbal stem cells decreased, and microstructural changes were observed in the fibroblasts of the sclera and cornea. We performed RNA-seq on scleral and corneal tissues of KO and normal control wild-type (WT) mice, which indicated a significant downregulation of the collagen synthesis-related pathway (extracellular matrix, ECM) in KO mice. Subsequent in vitro studies further indicated that LRRC46, a member of the important LRR protein family, primarily affected the formation of collagens. This study suggested that LRRC46 is a novel candidate gene for HM, influencing collagen protein VIII (Col8a1) formation in the eye and gradually altering the biomechanical structure of the cornea and sclera, thereby promoting the occurrence and development of HM.

Link between parental myopia and early-onset high myopia: Insights from a clinical retrospective analysis

INTRODUCTION

Genetic aetiology is suspected in the development of early-onset high myopia (spherical equivalent refractive error [SER] ≤-6.00 D at ≤6 years of age), considering that the role of environmental factors in inducing high myopia is improbable at an early age. Therefore, we aimed to understand if early-onset high myopia is associated with parental myopia in a clinical setting.

METHODS

A retrospective study was conducted in which information about demographics, age of apparent onset of myopia, refractive error, axial length, number of myopic parents, time spent outdoors and time spent on near-work was obtained from electronic medical records (EMR). It included 195 myopic individuals categorised into (1) Early-onset high myopes (EOHM): SER ≤ -6.00 D with age of presentation ≤6 years, (2) Early-onset low myopes (EOLM): SER > -6.00 D with age of apparent onset ≤6 years, (3) Late-onset high myopes (LOHM): SER ≤ -6.00 D with age of presentation and age of apparent onset >6 years and (4) Late-onset low myopes (LOLM): SER > -6.00 D with age of apparent onset >6 years.

RESULTS

Overall, 63% of individuals were found to have parental myopia. The proportion of individuals with EOHM, EOLM, LOHM and LOLM with parental myopia was 57%, 74%, 53% and 64%, respectively. After adjustment for age, gender and environmental factors, the odds of development of EOHM (Odds ratio: 0.78, 95% confidence interval: 0.25-2.48), EOLM (1.54, 0.65-3.67) or LOHM (0.70, 0.30-1.65) were similar in the presence of myopic parents, when compared with LOLM. The SER and axial length did not differ based on the number of myopic parents in any of these categories.

CONCLUSION

This retrospective analysis reveals that the presence of parental myopia, which was self-reported, did not induce additional risk for early-onset high myopia.

Influencing factors for pediatric eye disorders and health related quality of life: a cross-sectional study in Shanghai, China

Background

Myopia, strabismus, and ptosis are common pediatric eye diseases, which have a negative impact on children and adolescents in terms of visual function, mental health, and health-related quality of life (HRQoL). Therefore, this study focused on those pediatric eye diseases by analyzing their risk factors and HRQoL for the comprehensive management of myopia, strabismus, and ptosis.

Methods

A total of 363 participants (2-18 years old) were included in this study for risk factors analysis of myopia, strabismus, and ptosis. We collected demographic characteristics, lifestyle habits and eye care habits of these children and analyzed them by using univariable and multivariable logistic regression. In addition, we applied the Chinese version of Pediatric Quality of Life Inventory-Version 4.0 (PedsQL 4.0) to assess HRQoL in 256 children with strabismus and ptosis. Univariable and multivariable linear regression models were applied to evaluate potential influencing factors of HRQoL.

Results

Of all the participants, 140 had myopia, 127 had strabismus, and 145 had ptosis. Based on the multivariable logistic regression analysis model, we found that the history of parental myopia and daily average near-distance eye usage time were risk factors for myopia, and increased body mass index (BMI) was identified as a risk factor for strabismus and ptosis. Individuals with ptosis possessed decreased HRQoL. The multivariable linear regression model suggested that daily average near-distance eye usage time, light intensity during visual tasks, and daily average sleep duration had potential influences on HRQoL.

Conclusion

This is the first study to assess the risk factors and HRQoL of myopia, strabismus, and ptosis together. We identified risk factors for these common pediatric eye diseases to help doctors, parents, and teachers better manage them. Our study discovered that children with eye disorders exhibit a notably diminished HRQoL. Consequently, it emphasizes the necessity for increased social attention and mental health assistance for these children.

Axial length elongation profiles from 3 to 6 years in an Asian paediatric population: the Growing Up in Singapore Towards Healthy Outcomes birth cohort study (GUSTO)

AIMS

To determine axial length (AL) elongation profiles in children aged 3-6 years in an Asian population.

METHODS

Eligible subjects were recruited from the Growing Up in Singapore Towards Healthy Outcomes birth cohort. AL measurement was performed using IOLMaster (Carl Zeiss Meditec, Jena, Germany) at 3 and 6 years. Anthropometric measurements at birth, cycloplegic refraction at 3 and 6 years, questionnaires on the children's behavioural habits at 2 years and parental spherical equivalent refraction were performed. Multivariable linear regression model with generalised estimating equation was performed to determine factors associated with AL elongation.

RESULTS

273 eyes of 194 children were included. The mean AL increased from 21.72±0.59 mm at 3 years to 22.52±0.66 mm at 6 years (p<0.001). Myopic eyes at 6 years had greater AL elongation (1.02±0.34 mm) compared with emmetropic eyes (0.85±0.25 mm, p=0.008) and hyperopic eyes (0.74±0.16 mm, p<0.001). The 95th percentile limit of AL elongation was 1.59 mm in myopes, 1.34 mm in emmetropes and 1.00 mm in hyperopes. Greater birth weight (per 100 g, β=0.010, p=0.02) was significantly associated with greater AL elongation from 3 to 6 years, while parental and other behavioural factors assessed at 2 years were not (all p≥0.08).

CONCLUSION

In this preschool cohort, AL elongates at an average length of 0.80 mm from 3 to 6 years, with myopes demonstrating the greatest elongation. The differences in 95th percentile limits for AL elongation between myopes, emmetropes and hyperopes can be valuable information in identifying myopia development in preschool children.

A review of mechanism of action of outdoor exposure in preventing myopia incidence and progression

Various studies have suggested several environmental, pharmacological, medical, and optical interventions and some are in use but their efficacy in myopia control may be transient, and the cellular, molecular, and biochemical mechanisms involved unclear. Daylight exposure is currently regarded as an effective and enduring strategy in the control of myopia development and progression. However, the mechanism behind the effect of outdoor exposure and its association with genetic predisposition and other relatively more significant environmental factors on myopia is still a conundrum. This review focuses on survey-based and intervention-based studies carried out to propose a mechanism that accounts for myopia development and important for its control.

Advances in myopia control strategies for children

Myopia has long been a global threat to public health. Timely interventions are likely to reduce the risk of vision-threatening complications. There are both established and rapidly evolving therapeutic approaches to slow myopia progression and/or delay its onset. The effective methods for slowing myopia progression include atropine eye-drops, defocus incorporated multiple segments (DIMS) spectacle lenses, spectacle lenses with highly aspherical lenslets target (HALT), diffusion optics technology (DOT) spectacle lenses, red light therapy (RLT), multifocal soft contact lenses and orthokeratology. Among these, 0.05% atropine, HALT lenses, RLT and +3.00 peripheral addition soft contact lenses yield over 60% reduction in myopia progression, whereas DIMS, DOT and MiSight contact lenses demonstrate at least 50% myopia control efficacy. 0.05% atropine demonstrates a more optimal balance of efficacy and safety than 0.01%. The efficacy of 0.01% atropine has not been consistent and requires further validation across diverse ethnicities. Combining atropine 0.01% with orthokeratology or DIMS spectacles yields better outcomes than using these interventions as monotherapies. Increased outdoor time is an effective public health strategy for myopia prevention while recent studies suggest that 0.05% low-concentration atropine and RLT therapy have promising potential as clinical myopia prevention interventions for high-risk groups. Myopia control spectacle lenses, being the least invasive, are safe for long-term use. However, when considering other approaches, it is essential to ensure proper instruction and regular follow-ups to maintain safety and monitor any potential complications. Ultimately, significant advances have been made in myopia control strategies, many of which have shown meaningful clinical outcomes. However, regular use and adequate safety monitoring over extended durations are imperative to foster confidence that can only come from extensive clinical experience.

Effects of online family health education on myopia prevention in children by parental myopia: a randomized clinical trial

CLINICAL RELEVANCE

Online family health education may be effective for myopia prevention in children, and the effects may be different between children with myopic and non-myopic parents.

BACKGROUND

Myopia is a common cause of vision loss. The aims of this study were to evaluate the effects of online family health education on preventing the development of myopia in children, and to estimate whether the effects vary according to parental myopia.

METHODS

A cluster randomised trial including grade 1 and grade 2 children from 12 primary schools was conducted in Guangzhou, China. Weekly online family health education messages were sent to parents in the intervention group. Data collection included eye examinations of children and questionnaires completed by parents.

RESULTS

Among the 3123 children included at baseline (1703 boys [54.5%]; mean [SD] age, 6.83 [0.73] years), 2376 completed the follow-up after 3 years. The differences in the incidence of myopia and myopic shift between the study groups were not significant in total. However, the 3-year cumulative incidence rate of myopia in the intervention group (125 of 445 [28.1%]) was significantly lower than that in the control group (225 of 603 [37.3%]; difference, 9.2% [95% CI, -14.9% to -3.5%]; P = 0.001) among children with non-myopic parents. In parallel, among children with non-myopic parents, the mean myopic change in SER was less for the intervention group than for the control group (-1.10 D vs. -1.24 D; difference, 0.13 D [95% CI, 0.03 to 0.23 D]; P = 0.01).

CONCLUSIONS

Compared with children with myopic parents, online family health education was more effective in children with non-myopic parents. The incidence of myopia and myopic shift in refraction have been reduced in children with non-myopic parents. Further studies are needed to assess these differences by parental myopia.

Prevalence and associated factors of myopia in children and adolescents in Russia: the Ural Children Eye Study

BACKGROUND

To assess the prevalence of myopia and the distribution of ocular axial length as surrogate for myopic refractive error in school children in a population in Russia.

METHODS

The Ural Children Eye Study, a school-based case-control study, was conducted in Ufa/Bashkortostan/Russia from 2019 to 2022 and included 4933 children (age: 9.7±2.6 years; range: 6.2-18.8 years). The parents underwent a detailed interview and the children an ophthalmological and general examination.

RESULTS

Prevalence of any myopia (≤-0.50 dioptres (D)), minor myopia (-0.50 D to -1.0 D), moderate myopia (-1.01 D to -5.99 D) and high myopia (≤-6.0D) was 2187/3737 (46.2%; 95% CI 44.8% to 48.6%), 693/4737 (14.6%; 95% CI 13.6% to 15.6%), 1430/4737 (30.2%; 95% CI 28.9% to 31.5%) and 64/4737 (1.4%; 95% CI 1.0% to 1.7%), respectively. In the children aged 17+ years, prevalence of any, minor, moderate and high myopia was 170/259 (65.6%; 95% CI 59.8% to 71.5%), 130/259 (50.2%; 95% CI 44.1% to 56.3%), 28/259 (10.8%; 95% CI 7.0% to 14.6%) and 12/259 (4.6%; 95% CI 2.1% to 7.2%), respectively. After adjusting for corneal refractive power (beta: 0.09) and lens thickness (beta: -0.08), larger myopic refractive error was associated (r2=0.19) with older age (beta: 0.33), female sex (beta: 0.04), higher prevalence of maternal (beta: 0.15) and paternal (beta: 0.12) myopia, more time spent in school, with reading books or playing with the cell phone (beta: 0.05) and less total time spent outdoors (beta: 0.05). Axial length and myopic refractive error increased by 0.12 mm (95% CI 0.11 to 0.13) and -0.18 D (95% CI 0.17 to 0.20), respectively, per year of age.

CONCLUSIONS

In this ethnically mixed urban school children population from Russia, prevalence of any myopia (65.6%) and high myopia (4.6%) in children aged 17+ years was higher than in adult populations in the same region and it was lower than in East Asian school children, with similar associated factors.

The influence of the environment and lifestyle on myopia

BACKGROUND

Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of myopia during early childhood has heightened the risk of developing high myopia and related sight-threatening eye conditions in adulthood. This surge in myopia rates, occurring within a relatively stable genetic framework, underscores the profound influence of environmental and lifestyle factors on this condition. In this comprehensive narrative review, we shed light on both established and potential environmental and lifestyle contributors that affect the development and progression of myopia.

MAIN BODY

Epidemiological and interventional research has consistently revealed a compelling connection between increased outdoor time and a decreased risk of myopia in children. This protective effect may primarily be attributed to exposure to the characteristics of natural light (i.e., sunlight) and the release of retinal dopamine. Conversely, irrespective of outdoor time, excessive engagement in near work can further worsen the onset of myopia. While the exact mechanisms behind this exacerbation are not fully comprehended, it appears to involve shifts in relative peripheral refraction, the overstimulation of accommodation, or a complex interplay of these factors, leading to issues like retinal image defocus, blur, and chromatic aberration. Other potential factors like the spatial frequency of the visual environment, circadian rhythm, sleep, nutrition, smoking, socio-economic status, and education have debatable independent influences on myopia development.

CONCLUSION

The environment exerts a significant influence on the development and progression of myopia. Improving the modifiable key environmental predictors like time spent outdoors and engagement in near work can prevent or slow the progression of myopia. The intricate connections between lifestyle and environmental factors often obscure research findings, making it challenging to disentangle their individual effects. This complexity underscores the necessity for prospective studies that employ objective assessments, such as quantifying light exposure and near work, among others. These studies are crucial for gaining a more comprehensive understanding of how various environmental factors can be modified to prevent or slow the progression of myopia.

Risk factors for myopia among children and adolescents: an umbrella review of published meta-analyses and systematic reviews

AIMS

To identify potential risk factors for myopia in children and adolescents and assess the credibility of each evidence, providing reference for the development of myopia prevention strategies.

METHODS

We searched PubMed, Web of Science and Embase databases from inception to April 2022 to find systematic reviews or meta-analyses investigating the relationship between potential risk factors and myopia, and conducted an umbrella review. We recalculated the pooled effect sizes and 95% CIs of each potential risk factor through random-effects model, and reported its 95% prediction interval and between-study heterogeneity. Small-study effect and excess of significance bias were assessed to reveal potential publication bias.

RESULTS

Twelve publications were included in this umbrella review, including eight meta-analyses and four qualitative systematic reviews. Twenty-two factors were identified, of which 16 were analysed quantitatively. Ten factors showed statistically significant association with myopia. Myopia in one or two parents and per additional hour of time spend outdoors per week were rated as highly suggestive evidence. Near work and gender were evaluated as suggestive evidence. The other five factors are weak evidence.

CONCLUSIONS

We found several risk factors for myopia with different levels of evidence, of which parental myopia presented the strongest association with myopia in children and adolescents. Our findings contribute to a better understanding of the association between potential risk factors and myopia among children and adolescents and are important for informing parenting, education, clinical practice guidelines and public health policy.

PROSPERO TRIAL REGISTRATION NUMBER

CRD42022333053.

Myopia progression in school children with prolonged screen time during the coronavirus disease confinement

Background

Myopia, the most common refractive error, is a global public health problem with substantial visual impairment if left untreated. Several studies have investigated the association between increased near-work and restricted outdoor activities in children with myopia; however, such studies in children without myopia are scarce. We aimed to monitor the effect of the coronavirus disease-2019 (COVID-19) home confinement and mandatory virtual learning on myopic progression among myopic and non-myopic school-aged children.

Methods

We conducted a retrospective chart review of children aged 6 - 12 years attending regular visits to the pediatric ophthalmology clinic in a tertiary eye hospital in Eastern Province, Saudi Arabia. Cycloplegic refraction was determined from three visits at least six months apart: two visits before the start of the COVID-19 pandemic and one during the COVID-19 home confinement. Parents were asked about the time spent in near-work and outdoor activities, the devices used during virtual learning, and the demographic characteristics of the children. Statistical analyses were conducted to compare myopia progression before and during the COVID-19 home confinement.

Results

A total of 160 eyes of 80 children were analyzed. The boy (n = 46) to girl (n = 34) ratio was 1.4:1. The hyperopia (n = 131 eyes) to myopia (n = 29 eyes) ratio was 4.5:1. Most eyes exhibited a hyperopic shift before the confinement; however, all eyes displayed a myopic shift during the confinement. When comparing both eyes of the same individual, the more myopic or less hyperopic eye in the same child had a significantly greater myopic shift than the fellow eye (both P < 0.05). Children who used tablets showed a significant myopic shift (P < 0.05). Likewise, children in both age categories ( ≤ 8 and > 8 years), boys, those living in an apartment, and those having parents with bachelor's degrees experienced a significant myopic shift during COVID-19 home confinement compared to before (all P < 0.05). The mean myopic shift was greater in children aged > 8 years than in those aged ≤ 8 years. Children with and without a family history of myopia had a myopic shift in the mean spherical equivalent during COVID-19 home confinement; however, that of children with no family history was statistically significant (P < 0.05).

Conclusions

Progression of myopia accelerated in children during the COVID-19 pandemic. Excessive time spent on digital screen devices at near distances is considered a substantial environmental contributor to myopic shift in children. Further multicenter studies with extended follow-up periods are needed to assess the factors contributing to myopic progression in our population.

Trajectories of spherical equivalent refraction from grades 1 to 4 in Chinese children

BACKGROUND

The development trajectories of children's SER remain unknown. This study aimed to characterize spherical equivalent refraction (SER) trajectories during grades 1-4 in Chinese children.

METHODS

This prospective cohort study included 1226 first-grade non-myopic children from 12 public primary schools, randomly selected in two districts in Guangzhou, China. From November 2018 to March 2022, four-wave ocular examinations and questionnaire surveys have been completed. The group-based trajectory modeling was used to explore SER trajectories in grades 1-4.

RESULTS

All five trajectories showed an upward trend and rose faster after grade 2. Children in the sharp-developing (n = 44), high-developing (n = 136), and rapid-developing (n = 237) myopia groups developed myopia before grades 2, 3, and 4, respectively. Their SER development speed remained at a relatively high level after myopia, almost consistent with that before myopia. Children in the moderate-developing (n = 418) and low-developing (n = 391) non-myopia groups did not develop myopia before grade 4. Some characteristics in grade 1 were independently associated with SER trajectories, including sex, axial length, number of parents with myopia, residence, academic achievement, and the duration of outdoor activity. Based on the baseline characteristics, we established the model predicting the probability of children belonging to each group.

CONCLUSIONS

Myopia interventions are best started in grade 1 or preschool age. If interventions are not taken in time, the latest intervention window might be in grades 1, 2, and 3 for children with a high probability of belonging to the sharp-developing, high-developing, and rapid-developing myopia groups, respectively. The above probabilities might be predicted using the model we established. Moreover, the interventions for myopic children shouldn't be ignored.

Prevalence and related factors of children myopia in Pudong New Area, Shanghai: a cross-sectional study

OBJECTIVES

This study aimed to assess the prevalence and related factors of myopia among school-aged children after COVID-19 pandemic.

DESIGN

Cross-sectional study.

SETTING

Pudong New Area, Shanghai.

PARTICIPANTS

1722 children aged 7-9 randomly selected from 8 primary schools were screened from 1 February 2023 to 30 April 2023.

MAIN OUTCOME MEASURES

Children's height, weight and eye parameters were examined. Myopia was defined as a cycloplegic spherical equivalent ≤-0.50 dioptres in either eye. A vision-related behaviour questionnaire was applied to investigate the associations between myopia and its risk factors.

RESULTS

Of the 1722 individuals enrolled, 25.6% (456) had myopia. After adjusting other characteristics, the following factors were associated with an increased rate of myopia: age (9 years vs 7 years, adjusted OR (AOR) 1.84, 95% CI 1.18 to 2.85, p=0.007), parental myopia status (both myopia vs none, AOR 5.66, 95% CI 3.71 to 8.63, p<0.001; one myopia vs none, AOR 2.92, 95% CI 1.93 to 4.42, p<0.001), reading books too close (yes vs no, AOR 1.58, 95% CI 1.20 to 2.08, p=0.001), writing with a tilted head (yes vs no, AOR 1.37, 95% CI 1.05 to 1.77, p=0.019), sleep patterns (early to bed late to rise vs early to bed early to rise, AOR 1.52, 95% CI 1.02 to 2.26, p=0.039). By contrast, a higher monthly household income and the habit of reading while lying down were associated with lower risk of myopia.

CONCLUSIONS

The prevalence of myopia is of concern among young school-aged children after COVID-19. Correcting eye use behaviour and improving sleep habits may reduce myopia. Also, gender differences should be considered in prevention strategies for children's myopia.

Myopia progression risk assessment score (MPRAS): a promising new tool for risk stratification

Timely identification of individuals "at-risk" for myopia progression is the leading requisite for myopia practice as it aids in the decision of appropriate management. This study aimed to develop 'myopia progression risk assessment score' (MPRAS) based on multiple risk factors (10) to determine whether a myope is "at-risk" or "low-risk" for myopia progression. Two risk-score models (model-1: non-weightage, model-2: weightage) were developed. Ability of MPRAS to diagnose individual "at-risk" for myopia progression was compared against decision of five clinicians in 149 myopes, aged 6-29 years. Using model-1 (no-weightage), further 7 sub-models were created with varying number of risk factors in decreasing step-wise manner (1a: 10 factors to 1g: 4 factors). In random eye analysis for model-1, the highest Youden's J-index (0.63-0.65) led to the MPRAS cut-off score of 41.50-43.50 for 5 clinicians with a sensitivity ranging from 78 to 85% and specificity ranging from 79 to 87%. For this cut-off score, the mean area under the curve (AUC) between clinicians and the MPRAS model ranged from 0.89 to 0.90. Model-2 (weighted for few risk-factors) provided similar sensitivity, specificity, and AUC. Sub-model analysis revealed greater AUC with high sensitivity (89%) and specificity (94%) in model-1g that has 4 risk factors compared to other sub-models (1a-1f). All the MPRAS models showed good agreement with the clinician's decision in identifying individuals "at-risk" for myopia progression.

Topical Review: Studies on Management of Myopia Progression from 2019 to 2021

SIGNIFICANCE

Myopia is a common eye condition that increases the risk of sight-threatening complications. Each additional diopter increases the chance of complications. The purpose of this review was to make an overview of myopia control treatment options for children with myopia progression.In this nonsystematic review, we searched PubMed and Cochrane databases for English-language studies published from 2019 to September 2021. Emphasis was given to selection of randomized controlled trials. Nineteen randomized controlled trials and two retrospective studies were included. Topical atropine and orthokeratology remain the most used treatments, whereas lenses with novel designs are emerging treatments. Overall myopia progression in the treatment groups for low-dose atropine and orthokeratology was lower than in the control groups, and their efficacy was reported in several randomized controlled trials and confirmed by various systematic reviews and meta-analysis. The findings of myopia progression and axial elongation for the MiSight, defocus incorporated multiple segment spectacle lens, highly aspherical lenslets, and diffusion optics technology spectacle lens were comparable. Public health interventions to optimize environmental influences may also be important strategies to control myopia. Optimal choice of management of myopia depends on treatment availability, acceptability to child and parents, and specific patient features such as age, baseline myopia, and lifestyle. Eye care providers need to understand the advantages and disadvantages of each therapy to best counsel parents of children with myopia.

Investigation on the prevalence and influencing factors of myopia among children and adolescents in Liyang city

OBJECTIVE

To investigate the prevalence of myopia among children and adolescents in a local area (Liyang City) of China and analyze the influencing factors, so as to formulate corresponding preventive measures.

METHODS

A questionnaire survey was conducted, mainly investigating subjects' age, gender, residence (urban/rural areas), parental myopia, daily time spent outdoors, daily sleep time, distance between computer screen and eyes, less than one punch (10 cm) from the chest to the edge of the desk when reading and writing, one inch (3 cm) between finger and pen tip when writing, number of in-school physical education (PE) classes, length of TV watching, and size of TV. The myopia of all participants was recorded.

RESULTS

This study enrolled 7,948 children and adolescents, including 4,733 (59.55%) cases of myopia, 1,025 (12.90%) of astigmatism, 251 (3.16%) of hyperopia, and 699 (8.79%) of anisometropia respectively. There were 2,519 (53.22%) cases of myopia in the left eye and 2,214 (46.78%) in the right eye. Low, moderate, and high myopia were determined in 2,682 (56.67%), 1,583 (33.45%), and 468 (9.89%), respectively. In terms of spherical equivalent (SEQ), a statistically lower SEQ was observed in urban areas (-1.56±0.46 d) versus suburban counties (-1.17±0.33 d), and in females (-1.68±0.30 d) compared with males (-1.17±0.44 d). The mean SEQ gradually decreased with age. The prevalence of myopia was 63.84% (2,436/3,816) in females, statistically higher than that of 55.59% (2,197/4,132) in males (χ²=56.00, P < 0.0001). The incidence of myopia was statistically higher in urban areas (67.93% [3,321/4,889]) versus rural areas (46.16% [1,412/3,059]). Parental myopia, one inch between finger and pen tip when writing, daily time spent outdoors, daily sleep time, distance between computer screen and eyes, less than one punch from the chest to the edge of the desk when reading and writing, number of in-school PE classes, and daily length of TV watching were significantly correlated with the occurrence of myopia.

CONCLUSIONS

Parents are advised to pay attention to daily time spent outdoors, sleep time, distance between the computer screen and the eyes, distance between the chest and the edge of the table when reading and writing, and length of TV watching of their children. As far as schools are concerned, PE activity time should be properly maintained to ensure that children have enough outdoor exercise time to reduce eye fatigue.

Correlation of parental and childhood myopia in children aged 5-16 years in North India

Purpose

The aim of this study was to determine the correlation of parental and childhood myopia among school children aged 5-16 years in North India.

Methods

This study included a total of 1400 children aged 5-16 years in a district in North India. Visual acuity was measured using a Snellen's chart. Children with myopia after retinoscopy were worked up in detail in our institute and a history of parental myopia was taken.

Results

A total of 1400 students studying in class 5-10, aged between 5 and 16 years, were screened. A total of 487 students had myopia. Of the 487 myopes, 220 (45.2%) had parental myopia, of which 115 (30.1%) had myopia in both parents, 64 (19.3%) had mothers with myopia, and 41 (13.3%) had fathers with myopia. The prevalence of paternal (P = 0.001) and maternal (P = 0.002) myopia in myopes compared to parental myopia in emmetropes was found to be highly significant. There was a highly significant statistical correlation between maternal myopia and myopia in the child, when compared to the presence of myopia in both the parents (P = 0.007).

Conclusion

There was a statistically significant correlation between myopia in the parents and children, which was more significant in the mothers of the children.

Systematic Review and Meta-Analysis on the Impact of COVID-19 Pandemic-Related Lifestyle on Myopia

PURPOSE

To conduct a systematic review and meta-analysis to assess the effects of coronavirus disease 2019 (COVID-19) pandemic-related lifestyle on myopia outcomes in children to young adults.

METHODS

A systematic search was conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases (with manual searching of reference lists of reviews). Studies included assessed changes in myopia-related outcomes (cycloplegic refraction) during COVID and pre-COVID. Of 367 articles identified, 7 (6 prospective cohorts; 1 repeated cross-sectional study) comprising 6327 participants aged 6 to 17 were included. Quality appraisals were performed with Joanna Briggs Institute Critical Appraisal Checklists. Pooled differences in annualized myopic shifts or mean spherical equivalent (SE) during COVID and pre-COVID were obtained from random-effects models.

RESULTS

In all 7 studies, SE moved toward a myopic direction during COVID (vs pre-COVID), where 5 reported significantly faster myopic shifts [difference in means of changes: -1.20 to -0.35 diopters per year, [D/y]; pooled estimate: -0.73 D/y; 95% confidence interval (CI): -0.96, -0.50; P<0.001], and 2 reported significantly more myopic SE (difference in means: -0.72 to -0.44 D/y; pooled estimate: -0.54 D/y; 95% CI: -0.80, -0.28; P<0.001). Three studies reported higher myopia (SE ≤-0.50 D) incidence (2.0- to 2.6-fold increase) during COVID versus pre-COVID. Of studies assessing lifestyle changes, all 4 reported lower time outdoors (pre-COVID vs during COVID: 1.1-1.8 vs 0.4-1.0 hours per day, [h/d]), and 3 reported higher screen time (pre-COVID vs during COVID: 0.7-2.8 vs 2.4-6.9 h/d).

CONCLUSIONS

This review suggests more myopic SE shifts during COVID (vs pre-COVID) in participants aged 6 to 17. COVID-19 restrictions may have worsened SE shifts, and lifting of restrictions may lessen this effect. Evaluations of the long-term effects of the pandemic lifestyle on myopia onset and progression in large studies are warranted to confirm these findings.

Prevalence of Myopia and Its Associated Factors Among Japanese Preschool Children

Purpose

To investigate the prevalence of myopia and factors associated with spherical equivalent (SE), axial length (AL), and axial length to corneal radius of curvature (AL/CR) ratio among Japanese preschool children.

Study Design

Prospective observational study.

Methods

This cross-sectional study evaluated subjects aged 4–6 years from a preschool. Non-cycloplegic autorefraction was measured using the Spot Vision Screener, while AL and corneal radius (CR) were measured using the Myopia Master. Parental myopia and environmental factors were investigated using the myopia-related factor questionnaire. The worse eye with higher myopic SE was chosen for analysis, and multiple linear regression models was performed using AL, SE, and AL/CR ratio as dependent variables.

Results

A total of 457 out of 514 participants (239 males, 52.3%) aged 4–6 years (mean 4.77 ± 0.65 years) were included. The mean SE was 0.13 ± 0.63 D, AL was 22.35 ± 0.67 mm, CR was 7.76 ± 0.25 mm, and AL/CR ratio was 2.88 ± 0.72. The overall prevalence of myopia and high myopia were 2.9 and 0.2%, respectively. Multiple regression analysis showed that myopic SE was significantly associated with male sex (β = −0.14, p = 0.02) and parental myopia (β = −0.15, p = 0.04). Meanwhile, longer AL was significantly associated with older age (β = 0.13, p = 0.02), male sex (β = 0.44, p < 0.001), parental myopia (β = 0.24, p = 0.01), and screen time (including smartphones, tablets, and computers) (>1 h, β = 0.14, p = 0.04). A higher AL/CR was significantly associated with older age (β = 0.02, p < 0.001), male sex (β = 0.03, p < 0.001), ratio and parental myopia (β = 0.03, p = 0.02).

Conclusion

The prevalence of myopia and high myopia were 2.9 and 0.2%, respectively, among Japanese preschool children in 2021. Longer AL was associated with older age, male sex, parental myopia, and screen time in children aged 4–6 years. Children with a high risk of myopia can be identified early based on parental myopia information for early prevention.

Changes in Refractive Error Under COVID-19: A 3-Year Follow-up Study

INTRODUCTION

To investigate changes in refractive error in schoolchildren before and during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

This study included 2792 students, who underwent a 3-year follow-up from 2018 to 2020. All participants underwent yearly noncycloplegic refraction and ocular examinations. Time-related changes in sphere, cylinder, and spherical equivalent (SE) measurements in both genders were analyzed.

RESULTS

The myopic sphere (- 0.78 ± 1.83 vs. - 1.03 ± 1.91 D; P = 0.025) and SE (- 1.04 ± 1.90 vs. - 1.32 ± 1.99 D; P = 0.015) progressed significantly from 2018 to 2019. Female participants had a significantly greater change in SE than male participants (P < 0.05), and the low hyperopia, emmetropia, and mild myopia groups significantly deteriorated (P < 0.001) from 2018 to 2019. Significant differences in sphere change (- 0.21 ± 0.97 vs. - 0.36 ± 0.96 D; P < 0.001) and SE change (- 0.23 ± 0.99 vs. - 0.38 ± 0.98 D; P < 0.001) were noted between 2019-2018 and 2020-2019, respectively. The respective changes in cylinder were statistically similar (- 0.03 ± 0.53 vs. - 0.05 ± 0.62 D; P = 0.400).

CONCLUSIONS

The refractive status of schoolchildren showed an increasing myopic shift trend before and during the COVID-19 pandemic. The low hyperopia, emmetropia, and mild myopia groups were more sensitive to environmental changes during COVID-19 than before. The myopic shift was greater in female participants than male participants.

High prevalence of myopia and low hyperopia reserve in 4411 Chinese primary school students and associated risk factors

Purpose

To investigate the prevalence of myopia in Chinese primary school students and their ocular biometrics including axial length (AL), corneal radius of curvature (CRC) and spherical equivalent refraction (SER). To analyze their association with potential myopia risk factors, such as body mass index (BMI), cram school, time of outdoor activity and electronic screen use.

Methods

In this cross-sectional study of 4500 primary school students from 5 schools, participants underwent refraction using non-cycloplegic autorefractor and visual acuity testing. A follow-up study in the same schools was conducted in 2022. Myopia was defined as SER ≤ -0.50 diopter (D) and uncorrected visual acuity (UCVA) < 0.00 logMAR (6/6). Logistic regression models were used to determine factors associated with myopia.

Results

After excluding 389 participants, the overall prevalence of myopia was 33.6%. The prevalence of high myopia was 0.6%. The prevalence of myopia in girls was significantly higher than that in boys (37.6% vs. 30.0%, p < 0.001). The height, weight and BMI were significantly associated with AL (r = 0.471, r = 0.440, r = 0.276, p < 0.001, respectively). AL/CRC ratio was more highly correlated with SER than AL alone. Regression analysis showed that AL/CRC and hyperopia reserve were associated with myopia onset in the subsequent year (F = 201.557, p < 0.001; F = 68.934, p < 0.001). The cut point of hyperopia reserve for myopia in the subsequent year for grade 1 students was + 0.31D. Age (p < 0.001), parental myopia (p = 0.001) and lack of outdoor activity between classes (p = 0.049) were independently associated with higher prevalence rates of myopia.

Conclusion

The prevalence of myopia among Chinese schoolchildren is alarming high. Consistent with previous cross-sectional data, AL/CRC and hyperopia reserve could function as myopia detection indicators. The hyperopia reserve among children aged between 6 ~ 7 years was low. Healthcare providers need to raise parents’ awareness of the importance of regular eye examination and proper optical correction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02436-5.

Effect of Parental Myopia on Change in Refraction in Shanghai Preschoolers: A 1-Year Prospective Study

Background

To investigate the risk factors for change in refraction and refractive components in preschoolers.

Methods

Preschool children aged 3-5 years old, from the junior and the middle grades of seven randomly selected kindergartens in Jia Ding District, Shanghai, were followed for 1 year. Cycloplegic autorefraction (1% cyclopentolate) and axial length (AL) were measured at baseline and at 1-year follow-up. Questionnaires about parental myopia and environmental risk factors, such as time of outdoors and near work, were collected.

Results

A total of 603 right eyes of 603 children were included. Parental myopia was not associated with a change in refraction, but two myopic parents were associated with a longer change in AL (coefficient = 0.153, p = 0.006), after adjusted for baseline spherical refraction, age, gender, change in height, change in weight, and environment risk factors. In the multivariate analyses, boys showed a more myopic refraction shift than girls in 1 year (coefficient = -0.150, p = 0.008) and a quicker AL elongation (coefficient = 0.120, p = 0.008). Time of near work, such as watching television, using computer, reading and writing, and time of outdoor activities, was not associated with a change in refraction or AL.

Conclusions

In preschool age, environmental risk factors were not strongly associated with the change in refraction or refractive components. Parental myopia influences the refractive development of children continuously from infancy to preschool age, which might be the biological basis of school myopia.

Simulations to Assess the Performance of Multifactor Risk Scores for Predicting Myopia Prevalence in Children and Adolescents in China

Background: Myopia is the most common visual impairment among Chinese children and adolescents. The purpose of this study is to explore key interventions for myopia prevalence, especially for early-onset myopia and high myopia.

Methods: Univariate and multivariate analyses were conducted to evaluate potential associations between risk factor exposure and myopia. LASSO was performed to prioritize the risk features, and the selected leading factors were used to establish the assembled simulation model. Finally, two forecasting models were constructed to predict the risk of myopia and high myopia.

Results: Children and adolescents with persistently incorrect posture had a high risk of myopia (OR 7.205, 95% CI 5.999–8.652), which was 2.8 times higher than that in students who always maintained correct posture. In the cohort with high myopia, sleep time of less than 7 h per day (OR 9.789, 95% CI 6.865–13.958), incorrect sitting posture (OR 8.975, 95% CI 5.339–15.086), and siblings with spherical equivalent &lt;−6.00 D (OR 8.439, 95% CI 5.420–13.142) were the top three risk factors. The AUCs of integrated simulation models for myopia and high myopia were 0.8716 and 0.8191, respectively.

Conclusion: The findings illustrate that keeping incorrect posture is the leading risk factor for myopia onset, while the onset age of myopia is the primary factor affecting high myopia progression. The age between 8 and 12 years is the crucial stage for clinical intervention, especially for children with parental myopia.

Sleep Patterns and Myopia Among School-Aged Children in Singapore

Purpose

To evaluate the associations of sleep factors with myopia, spherical equivalent (SE), and axial length (AL) in elementary school-aged children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort.

Methods

This cross-sectional study included multi-ethnic children who participated in the GUSTO prospective birth cohort and were delivered in two major tertiary hospitals in Singapore (2009–2010). Sleep factors and myopia outcomes were assessed at the 8- and 9-year study visits, respectively. Parent-reported sleep quality was assessed with the Children's Sleep Habits Questionnaire (CSHQ) total scores. Additionally, each child's sleep duration, timing (bedtime; waketime), and the consistency of sleep duration or timing (i.e., the difference between weekends and weekdays) were parent-reported. Outcomes included cycloplegic SE, myopia (SE ≤ −0.5 D) and AL. Eye measurements from both eyes were included in the analyses. Multivariable linear or logistic regression with Generalized Estimating Equations were used to account for the correlation between paired eyes and confounders in the associations of sleep factors at age 8 and myopia at age 9.

Results

A total of 572 multi-ethnic children (49.5% boys; 56.1% Chinese) aged 9 years were included in the analyses. Overall, 37.3% of eyes were myopic. Children reported a mean total CSHQ score of 46 [standard deviation (SD) = 6]. The mean duration of sleep was 9.2 (SD = 1.0) hours per day (h/day), with 59.9% of children reporting sufficient sleep (≥9 h/day) based on guidelines recommended by the National Sleep Foundation, USA. The mean bedtime and wake time were 22:00 (SD = 00:53) and 07:08 (SD = 00:55), respectively. In multivariable regression models, total CSHQ scores, the duration of sleep, bedtime and wake time were not significantly associated with myopia, SE, or AL (p ≥ 0.05 for all), adjusting for gender, ethnicity, time outdoors, near-work, parental myopia, maternal education levels (and additionally the child's height when the outcome was AL). Similarly, the consistency of both the duration and timing of sleep (across weekends and weekdays) were not significantly associated with myopia, SE, or AL (p ≥ 0.05 for all).

Conclusion

In this cross-sectional study, sleep quality, duration, timing, and the consistency of specific sleep factors were not independently associated with myopia, SE, or AL among elementary school-aged children in Singapore. Large longitudinal studies are warranted to corroborate these results.

Premyopia at Preschool Age: Population-based Evidence of Prevalence and Risk Factors from A Serial Survey in Taiwan

PURPOSE

Premyopia at a young age carries a great risk of developing early-onset myopia, especially in regions with the epidemic of myopia, such as the developed areas in East Asia. This study aims to report the prevalence of premyopia and its risk factors in a Taiwan preschool population and lifestyle changes among premyopic preschoolers before and during the coronavirus disease 2019 (COVID-19) pandemic.

DESIGN

Repeated countywide population-based, cross-sectional study in Yilan County, northeastern Taiwan.

PARTICIPANTS

From 2014 through 2020, a total of 23,930 kindergarteners aged 5-6 years were identified in the Yilan Myopia Prevention and Vision Improvement Program (YMVIP). Of those, 21,761 (11,335 [52.1%] boys; mean age, 5.15 ± 0.37 years) were included for final analysis.

METHODS

Annual kindergarten-based eye examinations and myopia prevention strategies have been conducted since the commencement of the YMVIP in 2014. Refractive error was determined by cycloplegic autorefraction. The data of potential risk factors for myopia were gathered by caregiver-administered questionnaires.

MAIN OUTCOME MEASURES

The prevalence of premyopia (spherical equivalent [SE] > -0.5 diopter [D] and ≤ +0.75 D in the eye with less SE value) RESULTS: The prevalence of myopia (SE ≤ -0.5 D), premyopia, and hyperopia (SE > +0.75) was 10.7% (95% confidence interval [CI], 10.3%-11.1%), 52.0% (95% CI, 51.3%-52.7%), and 37.3% (95% CI, 36.7%-37.9%), respectively. Multinomial logistic regression analysis showed that premyopia prevalence was significantly associated with male gender (odds ratio [OR], 1.25; 95% CI, 1.18-1.32), caregiver myopia (OR, 1.46; 95% CI, 1.37-1.56), screen time ≥ 1 hour per weekdays (OR, 1.10; 95% CI, 1.04-1.17), 2-year exposure to myopia prevention strategy (OR, 0.59; 95% CI, 0.54-0.65), and college or higher education level of caregiver (OR, 0.91; 95% CI, 0.85-0.96). Even without large-scale school closure in Taiwan, there was a slight upward trend of increased time spent on screen-based devices during the COVID-19 pandemic.

CONCLUSIONS

Our findings showed that premyopia was the most common refractive error in a Taiwan preschool population. Premyopia was also associated with both parental and environmental myopiogenic factors. Longitudinal studies are warranted to examine the lifestyle change and myopic shift of premyopic preschoolers in the post-pandemic era.

Myopia Genetics and Heredity

Myopia is the most common eye condition leading to visual impairment and is greatly influenced by genetics. Over the last two decades, more than 400 associated gene loci have been mapped for myopia and refractive errors via family linkage analyses, candidate gene studies, genome-wide association studies (GWAS), and next-generation sequencing (NGS). Lifestyle factors, such as excessive near work and short outdoor time, are the primary external factors affecting myopia onset and progression. Notably, besides becoming a global health issue, myopia is more prevalent and severe among East Asians than among Caucasians, especially individuals of Chinese, Japanese, and Korean ancestry. Myopia, especially high myopia, can be serious in consequences. The etiology of high myopia is complex. Prediction for progression of myopia to high myopia can help with prevention and early interventions. Prediction models are thus warranted for risk stratification. There have been vigorous investigations on molecular genetics and lifestyle factors to establish polygenic risk estimations for myopia. However, genes causing myopia have to be identified in order to shed light on pathogenesis and pathway mechanisms. This report aims to examine current evidence regarding (1) the genetic architecture of myopia; (2) currently associated myopia loci identified from the OMIM database, genetic association studies, and NGS studies; (3) gene-environment interactions; and (4) the prediction of myopia via polygenic risk scores (PRSs). The report also discusses various perspectives on myopia genetics and heredity.

Dietary intake and associations with myopia in Singapore children

PURPOSE

To evaluate associations of dietary factors with myopia, spherical equivalent refractive error (SE) and axial length (AL) in children at age 9 from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort.

METHODS

We included 467 multi-ethnic children (933 eyes) who participated in the GUSTO prospective birth cohort and were delivered in two major hospitals in Singapore (2009-2010). At the 9-year visit, we assessed the 6-year incidence of myopia (between ages 3 to 9), cycloplegic SE and AL in children without myopia (SE ≤ -0.5 D in either eye) at the 3-year visit. Using a validated 112-item food frequency questionnaire, parents reported each child's average daily intake of dietary factors (nutrients and food groups) in the past month. Paired eyes were analysed using Generalised Estimating Equations with multivariable logistic or linear regression. Bonferroni corrections were applied, correcting for multiple comparisons between the 13 nutrients (p < 0.004) or 8 food groups (p < 0.006) and each outcome.

RESULTS

In children aged 9 years (51.0% boys; 56.3% Chinese), the 6-year incidence of myopia was 35.5%. Overall, the mean (SD) SE and AL were -0.3 (1.7) D and 23.4 (1.0) mm, respectively. In multivariable regression, macronutrients or micronutrients were not associated with incident myopia (p ≥ 0.004 for all), adjusting for total energy, gender, ethnicity, time outdoors, near-work and the number of myopic parents (additionally child's height for outcome AL). Similarly, all food groups (including refined grains, sugar-sweetened beverages, protein foods, fruits and vegetables) were not associated with incident myopia (p ≥ 0.006 for all). Additionally, none of the nutrients (p ≥ 0.004 for all) or food groups (p ≥ 0.006 for all) were associated with SE or AL.

CONCLUSIONS

Our study findings of no significant association between specific nutrients or food groups and incident myopia or SE or AL suggest that diet may not be associated with myopia in children aged 9 years. Well-conducted prospective studies in other populations may clarify the association.

Who needs myopia control?

Myopia has become a major visual disorder among school-aged children in East Asia due to its rising prevalence over the past few decades and will continue to be a leading health issue with an annual incidence as high as 20%-30%. Although various interventions have been proposed for myopia control, consensus in treatment strategies has yet to be fully developed. Atropine and orthokeratology stand out for their effectiveness in myopia progression control, but children with rapid progression of myopia require treatment with higher concentrations of atropine that are associated with increased rates of side effects, or with orthokeratology that carries risk of significant complication. Therefore, improved risk assessment for myopia onset and progression in children is critical in clinical decision-making. Besides traditional prediction models based on genetic effects and environmental exposures within populations, individualized prediction using machine learning and data based on age-specific refraction is promising. Although emerging treatments for myopia are promising and some have been incorporated into clinical practice, identifying populations who require and benefit from intervention remains the most important initial step for clinical practice.

Prediction of premyopia and myopia in Chinese preschool children: a longitudinal cohort

BACKGROUNDS

Myopia has become a global public health problem. Children with early onset of myopia are at particular risk of complications associated with myopia. Younger children and children with greater initial myopic refractive errors are at a greater risk of myopia progression. Therefore, it is essential to identify subjects at high risk of developing myopia to facilitate myopia prevention in the early stage, especially during the preschool period. The purpose of this study was to determine whether premyopia and myopia in preschool children can be predicted by easily obtainable parameters.

METHODS

Data was collected in a population-based cohort. Comprehensive examinations included height, weight, refraction, axial length (AL), and corneal radius of curvature (CR), with a follow-up of 2 years. Parental myopia history was obtained from a questionnaire. Myopia was defined as spherical equivalent (SE) ≤ - 0.50 D. Premyopia was defined as - 0.50 D < SE ≤ + 0.75 D. Multivariate linear regression models were fitted to determine the associations between these parameters at baseline and future SE. To predict premyopia and myopia, Cox proportional hazard regression analysis coupled with a nomogram was used.

RESULTS

A total of 830 children (433 boys and 397 girls) were included (40.83 ± 3.43 months old at baseline). A significantly negative relationship was observed in the multivariate analysis between baseline AL, AL/CR, two myopic parents, and the future SE after adjusting for age and gender (coefficient = - 0.291, coefficient = - 5.791, coefficient = - 0.273, respectively, both p <  0.001). Higher baseline AL, AL/CR (hazard ratio (HR) = 4.916, HR = 2.979, respectively, comparing the top quartile with the bottom quartile, both p <  0.001) and two myopic parents (HR = 1.756, compared to no myopic parents, p = 0.001) were associated with a higher risk of future onset of premyopia. From the nomogram, AL/CR was found to have the most enormous effect on survival. Different baseline AL and AL/CR values (both Log Rank p <  0.001) had different survival curves.

CONCLUSIONS

AL and AL/CR could be used as obtainable indicators for identifying subjects at high risk of developing premyopia and myopia in young preschool children.

Myopia in African Americans Is Significantly Linked to Chromosome 7p15.2-14.2

Purpose

The purpose of this study was to perform genetic linkage analysis and association analysis on exome genotyping from highly aggregated African American families with nonpathogenic myopia. African Americans are a particularly understudied population with respect to myopia.

Methods

One hundred six African American families from the Philadelphia area with a family history of myopia were genotyped using an Illumina ExomePlus array and merged with previous microsatellite data. Myopia was initially measured in mean spherical equivalent (MSE) and converted to a binary phenotype where individuals were identified as affected, unaffected, or unknown. Parametric linkage analysis was performed on both individual variants (single-nucleotide polymorphisms [SNPs] and microsatellites) as well as gene-based markers. Family-based association analysis and transmission disequilibrium test (TDT) analysis modified for rare variants was also performed.

Results

Genetic linkage analysis identified 2 genomewide significant variants at 7p15.2 and 7p14.2 (in the intergenic region between MIR148A and NFE2L3 and in the noncoding RNA LOC401324) and 2 genomewide significant genes (CRHR2 and AVL9) both at 7p14.3. No genomewide results were found in the association analyses.

Conclusions

This study identified a significant linkage peak in African American families for myopia at 7p15.2 to 7p14.2, the first potential risk locus for myopia in African Americans. Interesting candidate genes are located in the region, including PDE1C, which is highly expressed in the eyes, and known to be involved in retinal development. Further identification of the causal variants at this linkage peak will help elucidate the genetics of myopia in this understudied population.

Update and guidance on management of myopia. European Society of Ophthalmology in cooperation with International Myopia Institute

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.

IMI Risk Factors for Myopia

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.