A Cohort Study of Incident Myopia in Singaporean Children

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.

Factors influencing myopia stabilisation in young myopic adult Singaporeans

PURPOSE

To evaluate factors influencing stabilisation of myopia in the Singapore Cohort of Risk factors for Myopia.

METHODS

We evaluated the longitudinal natural history of 424 myopic participants from 1999 to 2022. The outcome was the change in myopia from the adolescence follow-up visit (aged 12-19 years) to the adulthood follow-up visit (aged 26-33 years). Association of predictive factors, including baseline spherical error, gender, ethnicity, parental myopia, time outdoor, near work and age at adolescence, was examined with the dichotomous outcome of adult myopia progression (≤ -1.00 dioptres (D) over 10 years) using multiple logistic regression and progression in linear regression models.

RESULTS

For the primary outcome, the mean rate of progression of the outcome was found to be -0.04±0.09 D per year from the adolescent to the adulthood follow-up visits. 82.3% (95% CI 78.3% to 85.8%) had myopia stabilisation, with progression of less than 1.00 D over 10 years while 61.3% (95% CI 56.5% to 66.0%) of the subjects had progression of less than 0.50 D. In logistic regression models, both male gender (p=0.035) and non-Chinese ethnicity (p=0.032) were more likely to achieve myopia stabilisation while in linear multivariate regression models, males had a significantly slower degree of myopia progression (p=0.021).

CONCLUSION

5 in 6 Singaporean young adults had myopia stabilisation. Male gender is 2 times and non-Chinese ethnicities are 2.5 times more likely to achieve myopia stabilisation. However, a proportion of myopes continue to exhibit a clinically significant degree of progression in adulthood.

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.

The association between pupillary responses and axial length in children differs as a function of season

The association between pupillary responses to repeated stimuli and adult refractive error has been previously demonstrated. This study evaluated whether this association exists in children and if it varies by season. Fifty children aged 8-17 years (average: 11.55 ± 2.75 years, 31 females) with refractive error between + 1.51 and - 5.69 diopters (non-cycloplegic) participated (n = 27 in summer, and n = 23 in winter). The RAPDx pupilometer measured pupil sizes while stimuli oscillated between colored light and dark at 0.1 Hz in three sequences: (1) alternating red and blue, (2) red-only, and (3) blue-only. The primary outcome was the difference in pupillary responses between the blue-only and red-only sequences. Pupillary constriction was greater in response to blue light than to red for those with shorter eyes in summer (β = - 9.42, P = 0.034) but not in winter (β = 3.42, P = 0.54). Greater constriction comprised faster pupillary escape following red light onset and slower redilation following stimulus offset of both colors (P = 0.017, 0.036, 0.035 respectively). The association between axial length and children's pupillary responses in summer, but not winter may be explained by greater light-associated release of retinal dopamine in summer. Shorter eyes' more robust responses are consistent with greater light exposure inhibiting axial elongation and reducing myopia risk.

Association between Global Myopia Prevalence and International Levels of Education

SIGNIFICANCE

The Global Myopia Prevalence and International Levels of Education study models national trends in educational performance with myopia prevalence in children; it examines the association of near work with myopia in the form of an ecologic analysis and also discusses how this may relate to educational frameworks.

PURPOSE

This study aimed to investigate the relationship between myopia prevalence and national educational performance.

METHODS

The prevalence of myopia in the 15- to 19-year age group in 35 regions was obtained from a meta-analysis by Holden et al. (Ophthalmology 2016;123:1036-1042) and matched with educational performance quantified by the Organisation for Economic Cooperation and Development Programme for International Student Assessment (PISA) testing from 2000 to 2018. A generalized estimating equation was used to describe the relationship between PISA scores and myopia prevalence. Clustering effects of country and chronological year were accounted for in the analysis. Linear and nonlinear terms of PISA scores using lines of best fit were further explored.

RESULTS

There is a significant positive relationship between Organisation for Economic Cooperation and Development PISA educational performance and myopia prevalence in teenagers with higher PISA scores correlating with higher myopia prevalence, even after accounting for chronological year (generalized estimating equation model: P = .001, .008, and .005 for math, science, and reading, respectively). Scatterplots with cubic and logistic fits indicated that PISA math showed the strongest relationship with myopia prevalence ( r2 = 0.64), followed by science ( r2 = 0.41) and reading ( r2 = 0.31).

CONCLUSIONS

These results strongly suggest that educational achievement at a national level is associated with higher myopia prevalence. Programme for International Student Assessment scores are a significant driver of many countries' education policies, and countries that have a balance between high PISA scores and lower myopia prevalence may be good models of educational policies to address the myopia public health issue.

Global risk factor analysis of myopia onset in children: A systematic review and meta-analysis

INTRODUCTION

This work aimed to comprehensively assess the risk factors affecting myopia in children to develop more effective prevention and treatment strategies. To this end, data from database were employed to assess the relationship between the incidence of myopia and its risk factors.

METHODS

We searched eight databases online in June 2022. Cohort studies were included that measured the connection between risk factors and myopia. Eligibility was not restricted by language. The Newcastle-Ottawa Scale (NOS) was used to measure the risk of bias and conducted GRADE evaluation to determine the certainty of evidence. Potential risk factors with positive or negative results were seen. Inplasy Registration: https://inplasy.com/inplasy-2022-4-0109/.

RESULTS

Evidence that risk factors for myopia are mixed, comprising both positive (20) and null (17) findings. In 19 cohort studies on 3578 children, girls were more likely to develop myopia (RR: 1.28 [1.22-1.35]). Myopia can occur at any age, from early childhood to late adulthood. Children whose parents had myopia were more likely to develop myopia. Longer outdoor activities time (RR: 0.97 [0.95-0.98]) and less near-work time (RR: 1.05 [1.02-1.07]) appeared to be significantly decrease the incidence of myopia. Children with lower SE, longer AL, a lower magnitude of positive relative accommodation, worse presenting visual acuity, deeper anterior chamber, and thinner crystalline lens may be related to myopia onset. The burden of myopia in underprivileged countries is higher than in developed countries (RR: 5.28 [2.06-13.48]). The quality of evidence for the evaluated factors was moderate to low or very low.

CONCLUSIONS

Genetic factors, environmental factors (such as excessive use of electronic products, and poor study habits) and lifestyle factors (such as lack of outdoor activities, poor nutrition, etc.) are the main risk factors for myopia in children. Myopia prevention strategies should be designed based on environmental factors, gender, parental myopia and eye indicators in order to explore a lifestyle that is more conducive to the eye health of children.

Risk Factors for Myopia: A Review

Due to the myopia prevalence increase worldwide, this study aims to establish the most relevant risk factors associated with its development and progression. A review search was carried out using PubMed, Web of Science, and Scopus databases to identify the main myopia risk factors. The inclusion criteria for the articles were those related to the topic, carried out in subjects from 5 to 30 years, published between January 2000 and May 2023, in English, and with the full text available. Myopia etiology has proven to be associated with both genetic and environmental factors as well as with gene-environment interaction. The risk of developing myopia increases in children with myopic parents (one parent ×2 times, two parents ×5 times). Regarding environmental factors, education is the main risk factor correlated with myopia prevalence increase. Further, several studies found that shorter distance (<30 cm) and longer time spent (>30 min) for near work increase the risk of myopia. Meanwhile, increased outdoor activity (>40 min/day) has been shown to be a key factor in reducing myopia incidence. In conclusion, the interventional strategy suggested so far to reduce myopia incidence is an increase in time outdoors and a reduction in the time spent performing near-work tasks.

Prevention and management of childhood progressive myopia: National consensus guidelines

Myopia is a major public health problem worldwide, including India, with the global prevalence of myopia increasing rapidly over decades. The clinical and socioeconomic impact of myopia is also expected to rise with rising prevalence. Therefore, the focus has now been shifted to prevent the incidence and progression of myopia. However, there is lack of any standardized guidelines for myopia management. This document aims to generate a national-level expert consensus statement on the management of childhood myopia in the Indian scenario. The expert panel of pediatric ophthalmologists consisted of 63 members who met in a hybrid meeting. A list of topics deliberating discussion in the meeting was provided to the experts in advance and they were instructed to provide their opinions on the matter during the meet. The panel of experts then gave their views on each of the items presented, deliberated on different aspects of childhood myopia, and reached a consensus regarding the practice patterns in the Indian scenario. In case of opposing views or lack of a clear consensus, we undertook further discussion and evaluated literature to help arrive at a consensus. A written document is prepared based on recommendations explaining definition of myopia, refraction techniques, components and methods of workup, initiation of anti-myopia treatment, type and timing of interventions, follow-up schedule, and indications for revised or combination treatment. This article formulates evidence-based guidelines for progressing myopes and pre-myopes and also establishes uniformity in the management of childhood myopia in the country.

TFOS Lifestyle: Impact of the digital environment on the ocular surface

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as "the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing". Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not 'diagnostic' of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).

Interventions recommended for myopia prevention and control among children and adolescents in China: a systematic review

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.

Deep learning system to predict the 5-year risk of high myopia using fundus imaging in children

Our study aims to identify children at risk of developing high myopia for timely assessment and intervention, preventing myopia progression and complications in adulthood through the development of a deep learning system (DLS). Using a school-based cohort in Singapore comprising of 998 children (aged 6-12 years old), we train and perform primary validation of the DLS using 7456 baseline fundus images of 1878 eyes; with external validation using an independent test dataset of 821 baseline fundus images of 189 eyes together with clinical data (age, gender, race, parental myopia, and baseline spherical equivalent (SE)). We derive three distinct algorithms - image, clinical and mix (image + clinical) models to predict high myopia development (SE ≤ -6.00 diopter) during teenage years (5 years later, age 11-17). Model performance is evaluated using area under the receiver operating curve (AUC). Our image models (Primary dataset AUC 0.93-0.95; Test dataset 0.91-0.93), clinical models (Primary dataset AUC 0.90-0.97; Test dataset 0.93-0.94) and mixed (image + clinical) models (Primary dataset AUC 0.97; Test dataset 0.97-0.98) achieve clinically acceptable performance. The addition of 1 year SE progression variable has minimal impact on the DLS performance (clinical model AUC 0.98 versus 0.97 in primary dataset, 0.97 versus 0.94 in test dataset; mixed model AUC 0.99 versus 0.97 in primary dataset, 0.95 versus 0.98 in test dataset). Thus, our DLS allows prediction of the development of high myopia by teenage years amongst school-going children. This has potential utility as a clinical-decision support tool to identify "at-risk" children for early intervention.

Fighting Myopia with Intermittent Nearwork Breaks: 20 Seconds Every 20 Minutes Might Not Be Enough Time

SIGNIFICANCE

Practitioners commonly prescribe the 20/20/20 rule with hopes that, if patients follow it, they will reduce their myopic progression. This clinical perspective provides evidence that 20-second break from nearwork every 20 minutes are not enough time to impact ocular growth.The ongoing myopia epidemic is a major public health crisis. Although the correlation between nearwork tasks such as reading, computers, and smartphones and myopia development is controversial, multiple lines of research suggest that sustained nearwork contributes to myopia development. Clinicians have proposed that children should take short breaks from nearwork with a 20-second break every 20 minutes being a common suggestion. Animal model data do strongly support the idea that multiple short breaks across time can cancel out the effects of longer periods of myopia-promoting activities. However, the animal model data also suggest that repeated episodes of 20 seconds are ineffective at reducing myopia development and instead indicate that sustained breaks of 5 minutes or more every hour are needed to negate myopiagenic effects.

Effect of Text Messaging Parents of School-Aged Children on Outdoor Time to Control Myopia: A Randomized Clinical Trial

IMPORTANCE

Myopia in school-aged children is a public health issue worldwide; consequently, effective interventions to prevent onset and progression are required.

OBJECTIVE

To investigate whether SMS text messages to parents increase light exposure and time outdoors in school-aged children and provide effective myopia control.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial was conducted in China from May 2017 to May 2018, with participants observed for 3 years. Of 528 965 primary school-aged children from Anyang, 3113 were randomly selected. Of these, 268 grade 2 schoolchildren were selected and randomly assigned to SMS and control groups. Data were analyzed from June to December 2021.

INTERVENTIONS

Parents of children in the SMS group were sent text messages twice daily for 1 year to take their children outdoors. All children wore portable light meters to record light exposure on 3 randomly selected days (2 weekdays and 1 weekend day) before and after the intervention.

MAIN OUTCOMES AND MEASURES

The co-primary outcomes were change in axial length (axial elongation) and change in spherical equivalent refraction (myopic shift) from baseline as measured at the end of the intervention and 3 years later. A secondary outcome was myopia prevalence.

RESULTS

Of 268 grade 2 schoolchildren, 121 (45.1%) were girls, and the mean (SD) age was 8.4 (0.3) years. Compared with the control group, the SMS intervention group demonstrated greater light exposure and higher time outdoors during weekends, and the intervention had significant effect on axial elongation (coefficient, 0.09; 95% CI, 0.02-0.17; P = .01). Axial elongation was lower in the SMS group than in the control group during the intervention (0.27 mm [95% CI, 0.24-0.30] vs 0.31 mm [95% CI, 0.29-0.34]; P = .03) and at year 2 (0.39 mm [95% CI, 0.35-0.42] vs 0.46 mm [95% CI, 0.42-0.50]; P = .009) and year 3 (0.30 mm [95% CI, 0.27-0.33] vs 0.35 mm [95% CI, 0.33-0.37]; P = .005) after the intervention. Myopic shift was lower in the SMS group than in the control group at year 2 (-0.69 diopters [D] [95% CI, -0.78 to -0.60] vs -0.82 D [95% CI, -0.91 to -0.73]; P = .04) and year 3 (-0.47 D [95% CI, -0.54 to -0.39] vs -0.60 D [95% CI, -0.67 to -0.53]; P = .01) after the intervention, as was myopia prevalence (year 2: 38.3% [51 of 133] vs 51.1% [68 of 133]; year 3: 46.6% [62 of 133] vs 65.4% [87 of 133]).

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, SMS text messages to parents resulted in lower axial elongation and myopia progression in schoolchildren over 3 years, possibly through increased outdoor time and light exposure, showing promise for reducing myopia prevalence.

TRIAL REGISTRATION

Chinese Clinical Trial Registry Identifier: ChiCTR-IOC-17010525.

Research trends and hotspots in the relationship between outdoor activities and myopia: A bibliometric analysis based on the web of science database from 2006 to 2021

Objectives

This study aimed to explore the current status, hotspots, and emerging research trends regarding the relationship between outdoor activities and myopia.

Methods

Publications on the relationship between outdoor activities and myopia from 2006 to 2021 were collected from the Web of Science Core Collection database. CiteSpace (version 6.1.R2) was used to performed a bibliometric analysis, and R software (version 4.1.0) was used to visualize the trends and hot map of publications.

Results

A total of 640 publications were collected and analyzed in the present study. China was the major contributor (n = 204), followed by the United States of America (n = 181) and Australia (n = 137). The United States of America had the most extensive foreign cooperation (centrality = 0.25), followed by Australia (centrality = 0.20). The National University of Singapore contributed the largest number of publications (n = 48), followed by Sun Yat-Sen University (n = 41) and the Australian National University (n = 41). Among institutions, Cardiff University in the United Kingdom had the most extensive foreign cooperation (centrality = 0.12), followed by the National University of Singapore (centrality = 0.11). Saw S from Singapore had the largest number of publications (n = 39), followed by Morgan I from Australia (n = 27) and Jonas J from Germany (n = 23). Investigative ophthalmology & visual science is the most important journal to study the relationship between outdoor activities and myopia. "Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050" published by Holden BA was the most cited paper in this field with 177 citations. Co-occurrence and burst analyses of keywords showed that research trends and hotspots in this field focused mainly on "risk," "prevention" and "school".

Conclusions

The influence of outdoor activities on myopia remains a concern. In the future, deeper cooperation between countries or institutions is required to explore the effects of outdoor activities on myopia. Outdoor activities for the prevention of myopia and reduction of the risk of myopia among school students may be the focus of future research.

Objective measures of viewing behaviour in children during near tasks

CLINICAL RELEVANCE

Objective assessment of near viewing behaviours performed in a laboratory setting showed that children demonstrate differing viewing distances and angles based on the type of task. Findings will contribute to our understanding of how near work influences myopia.

BACKGROUND

Evidence suggests that near working distance and viewing breaks are associated with myopia. The purpose of this study was to use an objective, continuously measuring range finding device to examine these viewing behaviours in children.

METHODS

Viewing distance, number of breaks, and head and eye angles were assessed in 16 non-myopic and 19 myopic children (ages 13.38 ± 4.14 years) using the Clouclip, an objective rangefinder, during five 15-minute near tasks, including (a) passive reading and (b) active writing on printed material, (c) passive viewing and (d) active engagement on an iPad, and (e) active engagement on a cell phone. Height and Harmon distance were measured. Viewing behaviours were analysed by task, refractive error group, and gender.

RESULTS

Mean viewing distances significantly differed by task (P < 0.001) and were highly correlated with children's Harmon distance and height for all near tasks (P < 0.05), except for the active printed task (P > 0.05). Viewing distances did not differ by gender or refractive error group. During each task, mean number of viewing breaks was 2.6 ± 4.1 and did not vary between task (P = 0.92) or refractive error group (P = 0.65). Head declination and total viewing angle varied by type of near task (P < 0.001 for both).

CONCLUSION

Children demonstrated differing viewing distances and viewing angles based on the type of near task they were performing. Viewing behaviours did not vary between myopic and non-myopic children. Findings will contribute to a better understanding of how near viewing behaviours can be quantified objectively and relationships with myopia.

Effect of atropine 0.01% on progression of myopia

Purpose

Myopia is the most common type of refractive error and the leading cause of functional visual loss. Increased risk of myopic maculopathy, retinal detachment, glaucoma and cataract has been seen with a myopia of as low as -1D. This study was done to determine the effect of atropine 0.01% eye drops on the progression of myopia in children >5 years.

Methods

This was a single-blind, prospective, randomized case-control study which included children of 5-15 years with myopia of >2D and were divided into treatment group (group 1) and placebo group (group 2). Children under treatment group were treated with application of 0.01% atropine at night. Children with history of any ocular surgery, chronic ophthalmic illness, squint and amblyopia were excluded from the study. The follow-up for myopia progression was done for two years.

Results

This study showed a significant difference in increase of spherical equivalent and axial length among treatment and placebo groups after a duration of two years. Total duration of follow up was twenty-four months. Mean increase in axial length of group 1 and 2 was 0.115 mm and 0.32 mm, respectively. Mean increase in refraction of groups 1 and 2 was -0.30 D and -0.88 D, respectively, showing significant change in axial length and refraction (P < 0.0001).

Conclusion

This study supports the use of atropine 0.01% eye drops in reducing the progression of myopia.

Myopia, its prevalence, current therapeutic strategy and recent developments: A Review

Myopia is a widespread and complex refractive error in which a person's ability to see distant objects clearly is impaired. Its prevalence rate is increasing worldwide, and as per WHO, it is projected to increase from 22% in 2000 to 52% by 2050. It is more prevalent in developed, industrial areas and affects individuals of all ages. There are a number of treatments available for the control of myopia, such as glasses, contact lenses, laser surgery, and pharmaceuticals agents. However, these treatments are less beneficial and have significant side effects. A novel molecule, 7-methylxanthine (7-MX), has been found to be a highly beneficial alternate in the treatment of myopia and excessive eye elongation. Many preclinical and clinical studies showed that 7-MX is effective for the treatment of myopia and is presently under phase II of clinical investigation. We have also investigated preclinical toxicity studies such as acute, sub-acute, sub-chronic, and chronic on rats. In these studies, 7-MX was found to be non-toxic as compared to other reported anti-myopic agents. Moreover, as an ideal drug, 7-MX is observed to have no or low toxicity, brain permeability, non-allergic, higher oral administration efficacy, and low treatment costs and thus qualifies for the long-term treatment of myopia. This review article on 7-MX as an alternative to myopia treatment will highlight recent findings from well-designed preclinical and clinical trials and propose a potential future therapy.

Light Signaling and Myopia Development: A Review

INTRODUCTION

The aim of this article was to comprehensively review the relationship between light exposure and myopia with a focus on the effects of the light wavelength, illuminance, and contrast on the occurrence and progression of myopia.

METHODS

This review was performed by searching PubMed data sets including research articles and reviews utilizing the terms "light", "myopia", "refractive error", and "illuminance", and the review was concluded in November 2021. Myopia onset and progression were closely linked with emmetropization and hyperopia. To better elucidate the mechanism of myopia, some of the articles that focused on this topic were included. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

RESULTS

The pathogenesis and prevention of myopia are not completely clear. Studies have provided evidence supporting the idea that light could affect eye growth in three ways. Changing the corresponding conditions will cause changes in the growth rate and mode of the eyes, and preliminary results have shown that FR/NIR (far red/near-infrared) light is effective for myopia in juveniles.

CONCLUSION

This review discusses the results of studies on the effects of light exposure on myopia with the aims of providing clues and a theoretical basis for the use of light to control the development of myopia and offering new ideas for subsequent studies.

Physical activity, time spent outdoors, and near work in relation to myopia prevalence, incidence, and progression: An overview of systematic reviews and meta-analyses

Myopia has reached epidemic levels in recent years. Stopping the development and progression of myopia is critical, as high myopia is a major cause of blindness worldwide. This overview aims at finding the association of time spent outdoors (TSO), near work (NW), and physical activity (PA) with the incidence, prevalence, and progression of myopia in children. Literature search was conducted in PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature, Cochrane Database of Systematic Reviews, ProQuest, and Web of Science databases. Systematic reviews (SR) and meta-analyses (MA) on the TSO, NW, and PA in relation to myopia were reviewed. Methodological nature of qualified studies were evaluated utilizing the Risk of Bias in Systematic Review tool. We identified four SRs out of which three had MA, which included 62 unique studies, involving >1,00,000 children. This overview found a protective trend toward TSO with a pooled odds ratio (OR) of 0.982 (95% confidence interval (CI) 0.979-0.985, I2 = 93.5%, P < 0.001) per extra hour of TSO every week. A pooled OR 1.14 (95% CI 1.08-1.20) suggested NW to be related to risk of myopia. However, studies associating myopia with NW activities are not necessarily a causality as the effect of myopia might force children to indoor confinement with more NW and less TSO. PA presented no effect on myopia. Though the strength of evidence is less because of high heterogeneity and lack of clinical trials with clear definition, increased TSO and reduced NW are protective against myopia development among nonmyopes.

Objective Measures of Near Viewing and Light Exposure in Schoolchildren during COVID-19

SIGNIFICANCE

Wearable sensors provide the opportunity for continuous objective measurement of the visual environment with high resolution. Our findings show that absolute and temporal properties of near viewing and time outdoors vary between myopic and nonmyopic schoolchildren, which are important considerations when studying refractive error pathogenesis.

PURPOSE

Numerous behavioral factors, including near work, time outdoors, electronic device use, and sleep, have been linked to myopia. The purpose of this study was to assess behaviors using subjective and objective methods in myopic and nonmyopic schoolchildren in the United States.

METHODS

Forty children (aged 14.6 ± 0.4 years) simultaneously wore two sensors for 1 week, a Clouclip for objective measurement of near viewing and light exposure and an Actiwatch for objective measurement of activity and sleep. Parents completed an activity questionnaire for their child. Near-viewing distance, daily duration, short-duration (>1 minute) and long-duration (>30 minutes) near-viewing episodes, light exposure, time outdoors, electronic device use, and sleep duration were analyzed by refractive error group and day of the week.

RESULTS

Objectively measured daily near-viewing duration was 6.9 ± 0.3 hours. Myopes spent more time in near + intermediate viewing than nonmyopes (P = .008) and had higher diopter hours (P = .03). Short- and long-duration near-viewing episodes were similar between groups (P < .05 for both). Daily light exposure and time outdoors were significantly lower for myopes (P < .05 for both). Electronic device use (12.0 ± 0.7 hours per day) and sleep duration (8.2 ± 0.2 hours per night) were similar between groups (P > .05 for both).

CONCLUSIONS

Objective and subjective measures confirm that myopic and nonmyopic schoolchildren exhibit different behaviors. Combining wearable sensors with questionnaires provides a comprehensive description of children's visual environment to better understand factors that contribute to myopia.

Effect of Violet Light-Transmitting Eyeglasses on Axial Elongation in Myopic Children: A Randomized Controlled Trial

The fact that outdoor light environment is an important suppressive factor against myopia led us to invent violet light-transmitting eyeglasses (VL glasses) which can transmit violet light (VL), 360-400 nm in wavelength, for the suppression of myopia, and can meanwhile block harmful ultraviolet waves from sunlight. The current study is a double-blinded randomized clinical trial to investigate the myopia-suppressive effect of VL glasses compared to conventional eyeglasses (placebo glasses) that do not transmit VL. The subjects were children aged from 6 to 12 years old, the population in which myopia progression is generally accelerated, and the myopia suppressive effect was followed up for two years in a city in Japan. Periodical ophthalmic examinations, interviews, and measurements of reflection and axial length under mydriasis were performed at the initial visit (the baseline) and at 1, 6, 12, 18, and 24 months. The mean change in axial length in the VL glasses group was significantly smaller than in the placebo glasses group when time for near-work was less than 180 min and when the subjects were limited to those who had never used eyeglasses before this trial (p < 0.01); however, this change was not significant without subgrouping. The suppressive rate for axial elongation in the VL glasses group was 21.4% for two years.

Wearable Sensors for Measurement of Viewing Behavior, Light Exposure, and Sleep

The purpose of this study was to compare two wearable sensors to each other and to a questionnaire in an adult population. For one week, participants aged 29.2 ± 5.5 years (n = 25) simultaneously wore a Clouclip, a spectacle-mounted device that records viewing distance and illuminance, and an Actiwatch, a wrist-worn device that measures illuminance and activity. Participants maintained a daily log of activities and completed an activity questionnaire. Objective measures of time outdoors, near (10–< 60 cm) and intermediate (60–100 cm) viewing, and sleep duration were assessed with respect to the daily log and questionnaire. Findings showed that time outdoors per day from the questionnaire (3.2 ± 0.3 h) was significantly greater than the Clouclip (0.9 ± 0.8 h) and Actiwatch (0.7 ± 0.1 h, p < 0.001 for both). Illuminance from the Actiwatch was systematically lower than the Clouclip. Daily near viewing duration was similar between the questionnaire (5.7 ± 0.6 h) and Clouclip (6.1 ± 0.4 h, p = 0.76), while duration of intermediate viewing was significantly different between methods (p < 0.001). In conclusion, self-reported time outdoors and viewing behaviors were different than objective measures. The Actiwatch and Clouclip are valuable tools for studying temporal patterns of behavioral factors such as near work, light exposure, and sleep.

COVID-19 PANDEMİ SÜRECİNDE ONLİNE EĞİTİMİN MİYOPİK ÇOCUKLARDA REFRAKSİYON DEĞERLERİ ÜZERİNE ETKİLERİNİN DEĞERLENDİRİLMESİ

AMAÇ: Bu çalışmanın amacı Covid-19 pandemisi nedeniyle uzaktan eğitim alan çocuklarda refraksiyon değişimlerini değerelendirmektir. GEREÇ VE YÖNTEM: Çalışmaya pandemi döneminde uzaktan eğitim alan ve en az 6 saat ekran maruziyeti olan ve gözlük reçete edilen 18 yaş altı 56 hasta dahil edildi. Snellen Eşeli ile görme keskinliklerine bakıldı. Hastanın tam gördüğü refraksiyon değerleri kaydedilip retrospektif olarak kayıtları tarandı. 2020’deki refraksiyon değerleri 2018 ve 2019’daki refraksiyon değerleri ile karşılaştırıldı. p

Objective and Subjective Behavioral Measures in Myopic and Non-Myopic Children During the COVID-19 Pandemic

Purpose

The coronavirus disease 2019 (COVID-19) pandemic required a shift to electronic devices for education and entertainment, with children more confined to home, which may affect eye growth and myopia. Our goal was to assess behaviors during COVID-19 in myopic and non-myopic children.

Methods

Parents completed a questionnaire for their children (ages 8.3 ± 2.4 years, n = 53) regarding visual activity in summer 2020, during the COVID-19 pandemic, as well as during school time and the summer before COVID-19. Children also wore an Actiwatch for 10 days in summer 2020 for objective measures of light exposure, activity, and sleep. Data were analyzed with repeated-measures analysis of variance.

Results

Subjective measures showed that during COVID-19, children exhibited increased electronic device use and decreased activity and time outdoors (P < 0.05 for all), while time spent doing near work was not different than during a typical school or summer session before COVID-19 (P > 0.05). Objective measures during COVID-19 showed that myopic children exhibited lower daily light exposure (P = 0.04) and less activity (P = 0.04) than non-myopic children.

Conclusions

Children demonstrated increased electronic device use and decreased activity and time outdoors during COVID-19, with myopic children exhibiting lower light exposure and activity than non-myopes. Long-term follow-up is needed to understand if these behavioral changes ultimately contribute to myopia progression.

Translational Relevance

Children's behaviors changed during the COVID-19 pandemic, which may have implications in eye growth and myopia.

New Polygenic Risk Score to Predict High Myopia in Singapore Chinese Children

Purpose

The purpose of this study was to develop an Asian polygenic risk score (PRS) to predict high myopia (HM) in Chinese children in the Singapore Cohort of Risk factors for Myopia (SCORM) cohort.

Methods

We included children followed from 6 to 11 years old until teenage years (12–18 years old). Cycloplegic autorefraction, ultrasound biometry, Illumina HumanHap 550, or 550 Duo Beadarrays, demographics, and environmental factors data were obtained. The PRS was generated from the Consortium for Refractive Error and Myopia genomewide association study (n = 542,934) and the Strabismus, Amblyopia, and Refractive Error in Singapore children Study (n = 500). The Growing Up in Singapore Towards healthy Outcomes Cohort study (n = 339) was the replication cohort. The outcome was teenage HM (≤ −5.00 D) with predictive performance assessed using the area under the curve (AUC).

Results

Mean baseline age ± SD was 7.85 ± 0.84 (n = 1004) and 571 attended the teenage visit; 23.3% had HM. In multivariate analysis, the PRS was associated with a myopic spherical equivalent with an incremental R² of 0.041 (95% confidence interval [CI] = 0.010, 0.073; P < 0.001). AUC for HM (0.77 [95% CI = 0.71–0.83]) performed better (P = 0.02) with the PRS compared with a model without (0.72 [95% CI = 0.65, 0.78]). Children at the top 25% PRS risk had a 2.34-fold-greater risk of HM (95% CI = 1.53, 3.55; P < 0.001).

Conclusions

The new Asian PRS improved the predictive performance to detect children at risk of HM.

Translational Relevance

Clinicians may use the PRS with other predictive factors to identify high risk children and guide interventions to reduce the risk of HM later in life.

Environmental and Behavioral Factors with Refractive Error in Israeli Boys

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.

Prediction of myopia onset with refractive error measured using non-cycloplegic subjective refraction: the WEPrOM Study

Background/aims

To evaluate the predictive performance of various predictors, including non-cycloplegic refractive error, for risk of myopia onset under pragmatic settings.

Methods

The Wenzhou Medical University Essilor Progression and Onset of Myopia Study is a prospective cohort study of schoolchildren aged 6–10 years from two elementary schools in Wenzhou, China. Non-cycloplegic refraction, ocular biometry and accommodation measurements were performed. Myopia was defined as spherical equivalent (SE) ≤−0.5 diopter (D). ORs using multivariable logistic regression were determined. Area under the curve (AUC) evaluation for predictors was performed.

Results

Schoolchildren who attended both baseline and 2-year follow-up were analysed (N=1022). Of 830 non-myopic children at baseline, the 2-year incidence of myopia was 27.6% (95% CI, 24.2% to 31.3%). Female gender (OR=2.2), more advanced study grades (OR=1.5), less hyperopic SE (OR=11.5 per D), longer axial length (AL; OR=2.3 per mm), worse presenting visual acuity (OR=2.3 per decimal), longer near work time (OR=1.1 per hour/day) and lower magnitude of positive relative accommodation (PRA; OR=1.4 per D) were associated with myopia onset. PRA (AUC=0.66), SE (AUC=0.64) and AL (AUC=0.62) had the highest AUC values. The combination of age, gender, parental myopia, SE, AL and PRA achieved an AUC of 0.74.

Conclusion

Approximately one in four schoolchildren had myopia onset over a 2-year period. The predictors of myopia onset include lower magnitude of PRA, less hyperopic SE, longer AL and female gender. Of these, non-cycloplegic SE and PRA were the top single predictors, which can facilitate risk profiling for myopia onset.

Risk factors of ocular morbidity among under-five years old children in Khartoum State- Sudan- 2020

BACKGROUND AND AIMS

Visual impairment in early childhood can significantly affect the development of visual, motor, and cognitive function and potentially lead to long-term adverse psychosocial consequences. This study aimed to identify the risk factors of ocular morbidity among under 5-year old children in Khartoum State, Sudan.

METHODS

A cross-sectional study was conducted in three tertiary eye care hospitals in Khartoum State, Sudan. The study included 391 children under the age of 5 years. The parent(s) were interviewed using a precoded, pretested, closed-ended questionnaire that included questions regarding socio-demographic profile and possible risk factors. Data were analyzed using Statistical Package for the Social Sciences (version 21.0). A P-value of less than .05 was regarded as significant.

RESULTS

There was a significant association between participants with diabetes mellitus and poor vision (P-value <.001). Two-thirds of participants (57%) with visual impairment had mothers, who reportedly attended antenatal care services regularly (P-value .001), revealing a significant statistical association. Maternal diseases, specifically diabetes, was identified as a risk factor for poor visual acuity in their offspring (P-value <.001). A significant relation was revealed between family history of eye disease and the degree of relationship to the affected participant (P-value <.001). There was an association between watching TV and current visual acuity (P-value <.001); as well as using mobile phones and current visual acuity (P-value <.001). Multilinear analysis revealed the stronger influence of TV watching rather than the use of mobile phones (P-value <.001).

CONCLUSIONS

Diabetes, diabetic mothers, a family history of ocular morbidity, watching television, and using mobile phones emerged as significant risk factors of ocular morbidity among children under the age of 5 years in this study. Many of these risk factors are either modifiable or controllable ocular morbidities among under-five children can be reduced with suitable interventions.

Effects of brief periods of clear vision on the defocus-mediated changes in axial length and choroidal thickness of human eyes

PURPOSE

To investigate the influence of brief, repeated periods of clear vision on the changes in axial length and choroidal thickness in response to short-term imposed defocus.

METHODS

The right eye of 16 young adults was exposed to 60 min episodes of continuous and interrupted defocus conditions (+3 DS and -3 DS) over five separate sessions, with the left eye optimally corrected for distance. For interrupted defocus, 2 min episodes of clear vision were imposed before each 15 min episode of myopic or hyperopic defocus (2/15 min). For hyperopic defocus, the effect of frequency of clear vision exposure was also assessed by imposing 1 min of clear vision before each 7.5 min of defocus (1/7.5 min). The right eye axial length and choroidal thickness were measured before, during and after each defocus condition.

RESULTS

After 60 min of continuous hyperopic defocus the eye elongated significantly by +9 ± 9 μm (p = 0.02). When exposed to interrupted (2/15 min) hyperopic defocus, axial elongation was significantly reduced by 77% compared to continuous hyperopic defocus (p = 0.03), with a final change of only +2 ± 10 μm relative to baseline. During interrupted (1/7.5 min) hyperopic defocus, axial elongation reduced slightly compared to continuous hyperopic defocus (+6 ± 8 μm relative to baseline, p = 0.12). For continuous myopic defocus, a reduction in axial length occurred but was not statistically significant (p > 0.05). A similar pattern of response was observed for choroidal thickness changes with continuous and interrupted (1/7.5 min) hyperopic defocus conditions.

CONCLUSIONS

Brief periods of clear vision can diminish axial elongation and choroidal thinning induced by hyperopic defocus exposure in human eyes. If hyperopic defocus contributes to myopia progression in humans, then interruption with brief periods of clear vision could reduce its myopiagenic effects.

IMI Prevention of Myopia and Its Progression

The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high myopia-associated optic neuropathy, are now some of the most common causes of irreversible blindness. Hence, strategies are warranted to reduce the prevalence of myopia and the progression to high myopia because this is the main modifiable risk factor for pathologic myopia. On the basis of published population-based and interventional studies, an important strategy to reduce the development of myopia is encouraging schoolchildren to spend more time outdoors. As compared with other measures, spending more time outdoors is the safest strategy and aligns with other existing health initiatives, such as obesity prevention, by promoting a healthier lifestyle for children and adolescents. Useful clinical measures to reduce or slow the progression of myopia include the daily application of low-dose atropine eye drops, in concentrations ranging between 0.01% and 0.05%, despite the side effects of a slightly reduced amplitude of accommodation, slight mydriasis, and risk of an allergic reaction; multifocal spectacle design; contact lenses that have power profiles that produce peripheral myopic defocus; and orthokeratology using corneal gas-permeable contact lenses that are designed to flatten the central cornea, leading to midperipheral steeping and peripheral myopic defocus, during overnight wear to eliminate daytime myopia. The risk-to-benefit ratio needs to be weighed up for the individual on the basis of their age, health, and lifestyle. The measures listed above are not mutually exclusive and are beginning to be examined in combination.

Rapid Myopic Progression in Childhood Is Associated With Teenage High Myopia

Purpose

The purpose of this study was to evaluate the association of childhood progression of spherical equivalent (SE) with high myopia (HM) in teenagers in the Singapore Cohort of Risk factors for Myopia (SCORM).

Methods

We included 928 SCORM children followed over a mean follow-up of 6.9 ± 1.0 years from baseline (6–11 years old) until their teenage years (12–19 years old). Cycloplegic autorefraction and axial length (AL) measurements were performed yearly. The outcomes in teenagers were HM (SE ≤ −5 diopter [D)], AL ≥ 25 mm, SE and AL. Three-year SE and AL progression in childhood and baseline SE and AL with outcomes were evaluated using multivariable logistic or linear regression models, with predictive performance of risk factors assessed using the area under the curve (AUC).

Results

At the last visit, 9.8% of teenagers developed HM and 22.7% developed AL ≥ 25 mm. In multivariate regression analyses, every −0.3 D/year increase in 3-year SE progression and every 0.2 mm/year increase in 3-year AL progression were associated with a −1.14 D greater teenage SE and 0.52 mm greater teenage AL (P values < 0.001). The AUC (95% confidence interval [CI]) of a combination of 3-year SE progression and baseline SE for teenage HM was 0.97 (95% CI = 0.95 – 0.98). The AUC of 3-year AL progression and baseline AL for teenage AL ≥ 25 mm was 0.91 (95% CI = 0.89 – 0.94).

Conclusions

Three-year myopia progression in childhood combined with baseline SE or AL were good predictors of teenage HM. Clinicians may use this combination of factors to guide timing of interventions, potentially reducing the risk of HM later in life.

Biological Mechanisms of Atropine Control of Myopia

Myopia is a global problem that is increasing at an epidemic rate in the world. Although the refractive error can be corrected easily, myopes, particularly those with high myopia, are susceptible to potentially blinding eye diseases later in life. Despite a plethora of myopia research, the molecular/cellular mechanisms underlying the development of myopia are not well understood, preventing the search for the most effective pharmacological control. Consequently, several approaches to slowing down myopia progression in the actively growing eyes of children have been underway. So far, atropine, an anticholinergic blocking agent, has been most effective and is used by clinicians in off-label ways for myopia control. Although the exact mechanisms of its action remain elusive and debatable, atropine encompasses a complex interplay with receptors on different ocular tissues at multiple levels and, hence, can be categorized as a shotgun approach to myopia treatment. This review will provide a brief overview of the biological mechanisms implicated in mediating the effects of atropine in myopia control.

Comparison of myopic progression in Finnish and Singaporean children

PURPOSE

To compare 3-year myopic progression between Finnish and Singaporean children.

METHODS

Myopic progression was compared between 9-year-old (mean age 9.7 ± 0.4 years, n = 92) and 11-year-old (mean age 11.7 ± 0.4 years, n = 144) Finnish (Finnish RCT) children and Singaporean children matched by age and refraction (SCORMMatched, n = 403) and 7- to 8-year-old Singaporean children matched only by refraction (SCORM Young, n = 186). Spherical equivalent (SE) was between -0.50 and -3.00 D. Refraction with cycloplegia was controlled annually for 3 years. Information on parental myopia, mother's education, time spent on near-work and outdoor time was gathered by parental questionnaire.

RESULTS

Three-year myopic progression was -2.08 ± 0.96 D and -1.30 ± 0.69 D in the Finnish RCT and Singaporean SCORM Matched 9-year-olds, respectively, and -1.34 ± 0.78 D, and -0.52 ± 0.44 D in the 11-year-olds, respectively (p < 0.001 between all groups). Myopic progression was fastest (-2.69 ± 0.89 D) in the SCORM 7-year-olds and similar between the SCORM Matched 9-year-olds and Finnish RCT 11-year-olds (p = 0.55). The Finnish RCT and SCORM Matched children showed significant differences in both daily near-work time (1.8 ± 1.0 versus 3.4 ± 1.9 hours per day, p < 0.001) and outdoor time (2.6 ± 0.9 versus 0.5 ± 0.4 hours per day, p < 0.001). These differences did not, however, explain the differences in myopic progression between the groups. More time spent outdoors was associated with less myopic progression in the Finnish RCT (r = 0.17, p = 0.009) group only. In the whole materials, greater myopic progression was associated with younger age at baseline (p < 0.001), younger age was associated with mother's higher education (p < 0.001), and mothers higher education was associated with myopia in both parents (p < 0.001).

CONCLUSION

Age at baseline was the most significant factor associated with myopic progression. However, at the same age and with the same initial refraction, the Finnish and Singaporean children showed different myopic progression. This result remains unexplained. Thus, age of myopia onset should be considered when comparing myopic progression between different samples and conducting treatment trials. Parental myopia may be a weak indicator of heredity of myopia.

Refractive change and incidence of myopia among rural Chinese children: the Handan Offspring Myopia Study

PURPOSE

To assess the refractive change and incidence of myopia, as well as their risk factors, among Chinese rural children aged 6-17 years.

METHODS

Children who completed the baseline vision examination of the Handan Offspring Myopia Study were re-examined, including both cycloplegic and non-cyloplegic autorefraction, with a mean follow-up time of 42.4±1.47 months.

RESULTS

A total of 601 children (68.5%) who completed both baseline and the follow-up examinations were enrolled. The cumulative refractive change and axial length change were -0.53±1.03 diopter and 0.39±0.46 mm (-0.15 diopter/year and 0.11 mm/year), respectively. A hundred and five out of the 469 non-myopic children at baseline become myopic at the follow-up, yielding a cumulative myopia incidence of 22.4% (95% CI: 18.6% to 26.2%), or annual myopia incidence of 6.3%. After adjustment, younger age (β=0.08, p<0.001), more myopic baseline refraction (β=0.31, p<0.001), larger difference between cycloplegic and non-cycloplegic refraction (β=-0.20, p=0.007) and more myopic paternal refraction (β=0.09, p=0.007) were found to be associated with more rapid myopic refractive change. More myopic baseline refraction (relative risk (RR), 95% CI: 0.19, 0.13-0.28, p<0.001) and more myopic paternal refraction (RR, 95% CI: 0.92, 0.84-1.00, p=0.039) were also associated with myopia incidence.

CONCLUSION

Relatively low myopic refractive change and myopia incidence were found in this study cohort. Children's refraction and paternal refraction were associated with both myopic refractive change and myopia incidence. Such information will be helpful for further comparisons in other rural versus urban areas of China, and other countries.

Annual Myopia Progression and Subsequent 2-Year Myopia Progression in Singaporean Children

Purpose

To investigate the association between 1-year myopia progression and subsequent 2-year myopia progression among myopic children in the Singapore Cohort Study of the Risk Factors for Myopia.

Methods

This retrospective analysis included 618 myopic children (329 male), 7 to 9 years of age (mean age, 8.0 ± 0.8) at baseline with at least two annual follow-up visits. Cycloplegic autorefraction was performed at every visit. Receiver operating characteristic (ROC) curves from multiple logistic regressions were derived for future fast 2-year myopia progression.

Results

Children with slow progression during the first year (slower than -0.50 diopter [D]/y) had the slowest mean subsequent 2-year myopia progression (-0.41 ± 0.33 D/y), whereas children with fast progression (faster than -1.25 D/y) in year 1 had the fastest mean subsequent 2-year myopia progression (-0.82 ± 0.30 D/y) (P for trend < 0.001). Year 1 myopia progression had the highest area under the curve (AUC) for predicting fast subsequent 2-year myopia progression (AUC = 0.77; 95% confidence interval [CI], 0.73-0.80) compared to baseline spherical equivalent (AUC = 0.70; 95% CI, 0.66-0.74) or age of myopia onset (AUC = 0.66; 95% CI, 0.61-0.70) after adjusting for confounders. Age at baseline alone had an AUC of 0.65 (95% CI, 0.61-0.69).

Conclusions

One-year myopia progression and age at baseline were associated with subsequent 2-year myopia progression in children 7 to 9 years of age.

Translational Relevance

Myopia progression and age at baseline may be considered by eye care practitioners as two of several factors that may be associated with future myopia progression in children.

The distribution of refraction by age and gender in a non-myopic Chinese children population aged 6-12 years

Background

The Prevalence of myopia is increasing in China. This study aimed to explore the distribution of spherical equivalent (SE) and its association with age, body mass index (BMI), gender in a non-myopic Chinese children population aged 6 to 12 years.

Methods

A total of 6362 students were recruited for ophthalmological investigation. Demographic and myopia related behavioral information was collected. SE value was measured by the Topcon RM-8900 or KR-800autorefractors. Potential independent risk factors were determined with Odds Ratio (OR) and 95% Confidence Interval (CI) by logistic regression analysis. We further constructed the nomogram model to predict future onset of myopia.

Results

Among the study population, 3900 (61.3%) were non-myopic. The prevalence of myopia is 38.0% for boys and 39.5% for girls. The average SE values were 0.50 ± 0.70 D for boys and 0.60 ± 0.80 D for girls. The mean SE values decreased with age, and the value of height and BMI took on a stable trend. Threshold values for myopia varied across age groups and gender. Paternal myopia (OR: 1.22, 95%CI: 1.01–1.48), near-work activities on weekends (2.56, 1.17–5.61), and outdoor activities (0.68, 0.54–0.86) were associated with potential myopic in students.

Conclusion

A series of age-gender based SE threshold values were established to predict myopia in Chinese children aged 6 to 12 years. High risk factors for myopia included paternal myopia, near-work activities on weekends, and outdoor activities. Countermeasures are encouraged to reverse the increasing trend of myopia in children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-020-01709-1.

Sleeping late is a risk factor for myopia development amongst school-aged children in China

Myopia, a leading cause of distance vision impairment, is projected to affect half of the world's population in 30 years. We analysed the relationship between certain demographic, environmental, and behavioural factors and myopia from a 2-year school-based, prospective trial conducted in Shanghai, China. This trial enrolled 6295 school-aged children at baseline and followed them up for 24 months. The relationship between abovementioned factors and myopia was examined and the role of sleep in childhood myopia development was highlighted. Our results suggest that 'sleeping late' is a risk factor for myopia prevalence at baseline (odds ratio [OR] = 1.55, p = 0.04), 2-year myopia incidence (odds ratio [OR] = 1.44, p = 0.02) and progression over 24 months (p = 0.005), after adjusting for residency area, age, gender, sleep duration, and time spent outdoors. The identification and consistency of results with late sleepers being a susceptible group to both myopia onset and progression suggests a complex relationship between circadian rhythm, indoor environment, habitual indoor activities and myopia development and progression. These results can offer new insights to future myopia aetiology studies as well as aid in decision-making of myopia prevention strategies.

The Association between Childhood Myopia Prevalence and Environmental Factors in China: A Metaregression Analysis

Background. Myopia prevalence varies across the country among schoolchildren in China. Recently, environmental factors have been shown to be important in myopia development and progression. Given China’s geographical diversity with variable environmental factors, we investigated whether environmental factors could explain the regional variations in myopia in mainland China. Methods. We searched PubMed, Web of Science, and Chinese Science Periodical Databases for studies with reports of myopia prevalence in schoolchildren in mainland China from the years 1979 to 2019. Data on environmental factors (annual sunshine hours, temperature, and population density) were obtained from past records. A random-effect univariate metaregression analysis was used to investigate the association between the environmental factors and myopia prevalence and to determine the proportion of variation in regional myopia prevalence that can be attributed to each factor. Results. Forty-nine eligible studies were identified that included 666,864 schoolchildren aged 6 to 20 years. The pooled estimate of myopia prevalence was 32.88% (95% confidence interval: 26.69–39.08%). Univariate metaregression analysis indicated that annual sunshine hours (27.97% of variance), annual temperature (24.66%), and population density (7.06%) significantly contributed to regional myopia prevalence variation (each $p<0.05$ ), while seasonal variation in sunshine hours (1.54%, $p=0.604$ ) was not a significant predictor of myopia prevalence. However, only annual sunshine hours was significantly associated with myopia prevalence in the multivariate metaregression model. Conclusion. Myopia prevalence in children was higher in regions with low sunshine hours, and annual sunshine hours was significantly associated with regional variation in myopia prevalence in mainland China.

Validation of the Clouclip and utility in measuring viewing distance in adults

PURPOSE

To validate the Clouclip, a continuously measuring objective rangefinder, and examine viewing behaviours during various near tasks in non-myopic and myopic adults.

METHODS

In experiment 1, five Clouclip devices were utilised. An infrared camera was used to visualise and measure infrared beam size and angle. Repeatability for distance tracking was assessed from 5 to 120 cm in 5 cm increments. Accuracy of distance tracking was investigated for paper and iPad targets, spatial integration was calculated, effects of target tilt were determined and light measurements were compared to a lux meter. In experiment 2, viewing behaviour was assessed in 41 subjects (21 non-myopic, 20 myopic) during four 15-min near tasks; (1) passive reading of printed material, (2) active writing on printed material, (3) passive viewing on an electronic device and (4) active engagement on an electronic device. Working distance was compared between tasks and refractive error groups.

RESULTS

Clouclip distance tracking showed good repeatability, with a mean difference of 0.34 cm and limits of agreement of ±2.0 cm. Clouclip-measured and actual distances were highly correlated for paper and electronic targets from 5 to 120 cm, with mean differences and limits of agreement of 3.96 ± 13.78 cm and 4.48 ± 8.92 cm, respectively; variability increased for distances >100 cm. Tracking ability increased with larger target sizes; tracking was accurate when the target occupied 1.5%-20.3% of tracking beam area, depending on distance and with target tilt up to ±60 degrees. Clouclip- and lux meter-measured ambient illumination were highly correlated for a wide range of intensities (r = 0.96, p < 0.001), but with greater variability for intensities >20 000 lux. The Clouclip infrared beam was measured to have a diameter of 25.6 ± 2.2° and a downward angle of 10.3 ± 0.5°. For subject testing, viewing distance was significantly closer for active and passive printed tasks (29.5 ± 6.7 cm and 33.2 ± 8.8 cm, respectively) than for active and passive electronic tasks (35.4 ± 8.0 cm and 40.8 ± 10.4 cm, respectively), with no differences between refractive error groups (p = 0.88).

CONCLUSIONS

The Clouclip performed well in measuring near and intermediate distances and could distinguish between indoor (<1000 lux) and outdoor (>1000 lux) illumination. A closer working distance was observed for printed tasks compared to those on an iPad, with no difference in viewing distance between non-myopic and myopic adults.

The Effect of Refractive Error on Melanopsin-Driven Pupillary Responses

Purpose

Human and animal studies suggest that light-mediated dopamine release may underlie the protective effect of time outdoors on myopia development. Melanopsin-containing retinal ganglion cells may be involved in this process by integrating ambient light exposure and regulating retinal dopamine levels. The study evaluates this potential involvement by examining whether melanopsin-driven pupillary responses are associated with adult refractive error.

Methods

Subjects were 45 young adults (73% female, 24.1 ± 1.8 years) with refractive errors ranging from –6.33 D to +1.70 D. The RAPDx (Konan Medical) pupillometer measured normalized pupillary responses to three forms of square-wave light pulses alternating with darkness at 0.1 Hz: alternating long wavelength (red, peak at 608 nm) and short wavelength (blue, peak at 448 nm), followed by red only and then blue only.

Results

Non-myopic subjects displayed greater pupillary constriction in the blue-only condition and slower redilation following blue light offset than subjects with myopia (P = 0.011). Pupillary responses were not significantly different between myopic and non-myopic subjects in the red-only condition (P = 0.15). More hyperopic/less myopic refractive error as a continuous variable was linearly related to larger increases in pupillary constriction in response to blue-only stimuli (r = 0.48, P = 0.001).

Conclusions

Repeated light exposures to blue test stimuli resulted in an adaptation in the pupillary response (more constriction and slower redilation), presumably due to increased melanopsin-mediated input in more hyperopic/less myopic adults. This adaptive property supports a possible role for these ganglion cells in the protective effects of time outdoors on myopia development.

Low physical activity and higher use of screen devices are associated with myopia at the age of 16-17 years in the CCC2000 Eye Study

PURPOSE

To determine the myopia prevalence in a Danish cohort aged 16-17 years and its relation to physical activity and use of screen-based electronic devices.

METHODS

The Copenhagen Child Cohort 2000 Eye Study is a prospective, population-based, observational study. Information about use of screen devices and physical activity was obtained using questionnaires. Myopia was defined as non-cycloplegic subjective spherical equivalent refraction ≤-0.50 D in right eye.

RESULTS

We included 1443 participants (45% boys) with a median age (±IQR) of 16.6 years (±0.3). The prevalence of myopia was 25% (CI95% 23-28, n = 360) with no differences between sexes (p = 0.10). The odds ratio (OR) for myopia was 0.57 (CI95% 0.42-0.76, p = 0.0002) in participants physically active 3-6 hr/week (n = 502) and 0.56 (CI95% 0.42-0.76, p = 0.0002) if active >6 hr/week (n = 506), both compared with participants physically active <3 hr/week (n = 396). The use of screen devices >6 hr/day was associated with increased OR for myopia compared with screen device use <2 hr/day in both weekdays (OR = 1.95, CI95% 1.16-3.30, p = 0.012) and weekends (OR = 2.10, CI95% 1.17-3.77, p = 0.013).

CONCLUSION

In this cohort of healthy 16-17-year olds, lower physical activity and more use of screen devices contributed significantly to the observed 25% prevalence of myopia with a roughly doubled risk of having myopia if physically active <3 hr/week or if using screen devices >6 hr/day. Our results support physical activity being a protective factor and near work a risk factor for myopia in adolescents.

Prevalence of myopia and associated risk factors among primary students in Chongqing: multilevel modeling

Background

The prevalence of myopia and associated risk factors among children in Chongqing has not yet been determined. This study investigated the prevalence of myopia and possible relationships between myopia and several related factors among school children in Chongqing.

Methods

This cross-sectional study assessed a sample of 997 children (7–13 years of age) attending primary school in Chongqing. Data were obtained from visual acuity and refractive error measurements and a structured questionnaire. Myopia was defined as visual acuity < 5.0 and refractive error (spherical equivalent) of < − 0.50 diopters (D) in either eye. Multilevel modeling was applied to investigate potential risk factors.

Results

The overall prevalence of myopia was 33.9% [95% confidence interval (CI) = 31.0–36.8]; myopia prevalence significantly increased with age. Girls were at a higher risk of myopia than boys [odds ratio (OR) = 1.449, 95% CI = 1.060–1.979]. Children with paternal myopia (OR = 2.130, 95% CI = 1.376–3.297) or maternal myopia (OR = 1.861, 95% CI =1.153–3.002) had a higher risk of myopia than those without myopic parents. Children who spent more than 1 h daily outdoors were less likely to have myopia; meanwhile, children who did homework more than 3 h daily (OR = 2.237, 95% CI = 1.041–4.804), watched television more than 3 h daily (OR = 2.106, 95% CI = 1.200–3.697), or played electronics more than 1 h daily (OR = 2.983, 95% CI = 2.088–4.262) had a higher risk of myopia.

Conclusions

Myopia in school children is a serious public health problem in Chongqing. Myopia was significantly positively associated with higher age, female sex, parental myopia, and spending a long time indoors; notably, playing with electronics had the greatest influence on the risk of myopia.

Protective effects of increased outdoor time against myopia: a review

Myopia has become a major cause for concern globally, particularly in East Asian countries. The increasing prevalence of myopia has been associated with a high socioeconomic burden owing to severe ocular complications that may occur with progressive myopia. There is an urgent need to identify effective and safe measures to address the growing number of people with myopia in the general population. Among the numerous strategies implemented to slow the progression of myopia, longer time spent outdoors has come to be recognized as a protective factor against this disorder. Although our understanding of the protective effects of outdoor time has increased in the past decade, considerably more research is needed to understand the mechanisms of action. Here, we summarize the main potential factors associated with the protective effects against myopia of increased outdoor time, namely, exposure to elevated levels and shorter wavelengths of light, and increased dopamine and vitamin D levels. In this review, we aimed to identify safe and effective therapeutic interventions to prevent myopia-related complications and vision loss.

Associations between near work, outdoor activity, parental myopia and myopia among school children in Aba, Nigeria

AIM

To assess the influence of near work, time outdoor and parental myopia on the prevalence of myopia in school children in Aba, Nigeria.

METHODS

Primary and secondary school children aged between 8 and 15y were randomly recruited from 12 schools in Aba. Information on family history, near work and outdoor activity was obtained using myopia risk factor questionnaire. Cycloplegic refraction was performed using autorefraction technique. Myopia was defined as spherical equivalent refraction (SER) ≤-0.50 D in the poorer eye. Data were analysed for 1197 (male: 538 and female: 659) children with full relevant data.

RESULTS

Risk of developing myopia was positively associated with parental myopia [odds ratio (OR): 6.80; 95%CI, 2.76-16.74; P<0.01) for one myopic parent and (OR: 9.47; 95%CI, 3.88-23.13; P<0.01) for two myopic parents, longer daily reading hour (OR: 1.21; 95%CI, 1.03-1.42; P=0.02) and less time outdoors (OR: 0.8; 95%CI, 0.74-0.87; P<0.01).

CONCLUSION

Parental history of myopia is the most important risk factor associated with myopia. In addition, children with both parents being myopic has increased odds of developing myopia than those with one myopic parent. It is recommended therefore, that children spend more time outdoors as this could reduce the prevalence and progression of myopia.

Morphological ciliary muscle changes associated with form deprivation-induced myopia

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.

Role of Parental Refractive Status in Myopia Progression: 12-Year Annual Observation From the Guangzhou Twin Eye Study

Purpose

We investigate the impact of parental myopia on spherical equivalent (SE) progression and axial length (AL) elongation.

Methods

Children and their parents were invited for annual examinations from 2006 (baseline). Cycloplegic autorefraction and AL were measured at each visit. Parental refractive status was determined using refraction data from their baseline visit. Children were classified into five groups: no myopic parents (non-non), only one moderately myopic parent (non-moderate), only one highly myopic parent (non-high), two moderately myopic parents (moderate-moderate), and one moderately myopic or more severe and one highly myopic parent (moderate-high/high-high). The relationship between progression of SE and AL with parental refractive status was estimated by linear mixed-effects models. Data from 2006 to 2017 were analyzed in the current study.

Results

A total of 1831 children were enrolled (mean age, 11 ± 2.7 years; mean standard error, -0.49 ± 2.16 diopters [D] at baseline. Myopia progressed faster for children with parental myopia (non-non group as reference, all P < 0.05), while AL elongation mirrored the change in SE (all P < 0.001 except for non-mod group P = 0.12). As for the age-specific change in SE and AL, children in the mod-high/high-high group presented with the fastest progression. Children with highly myopic parents were at higher risks of being highly myopic during adulthood (odds ratio = 13.98 and 25.71 for non-high and mod-high/high-high groups; both P < 0.001).

Conclusions

SE progresses and AL elongates at a faster rate at an earlier age in children with parental myopia. Children with highly-myopic parents have higher risks of being highly myopic during adulthood.