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.

Trans-ancestral genome-wide association study of longitudinal pubertal height growth and shared heritability with adult health outcomes

BACKGROUND

Pubertal growth patterns correlate with future health outcomes. However, the genetic mechanisms mediating growth trajectories remain largely unknown. Here, we modeled longitudinal height growth with Super-Imposition by Translation And Rotation (SITAR) growth curve analysis on ~ 56,000 trans-ancestry samples with repeated height measurements from age 5 years to adulthood. We performed genetic analysis on six phenotypes representing the magnitude, timing, and intensity of the pubertal growth spurt. To investigate the lifelong impact of genetic variants associated with pubertal growth trajectories, we performed genetic correlation analyses and phenome-wide association studies in the Penn Medicine BioBank and the UK Biobank.

RESULTS

Large-scale growth modeling enables an unprecedented view of adolescent growth across contemporary and 20th-century pediatric cohorts. We identify 26 genome-wide significant loci and leverage trans-ancestry data to perform fine-mapping. Our data reveals genetic relationships between pediatric height growth and health across the life course, with different growth trajectories correlated with different outcomes. For instance, a faster tempo of pubertal growth correlates with higher bone mineral density, HOMA-IR, fasting insulin, type 2 diabetes, and lung cancer, whereas being taller at early puberty, taller across puberty, and having quicker pubertal growth were associated with higher risk for atrial fibrillation.

CONCLUSION

We report novel genetic associations with the tempo of pubertal growth and find that genetic determinants of growth are correlated with reproductive, glycemic, respiratory, and cardiac traits in adulthood. These results aid in identifying specific growth trajectories impacting lifelong health and show that there may not be a single "optimal" pubertal growth pattern.

Topical Atropine for Childhood Myopia Control: The Atropine Treatment Long-Term Assessment Study

Importance

Clinical trial results of topical atropine eye drops for childhood myopia control have shown inconsistent outcomes across short-term studies, with little long-term safety or other outcomes reported.

Objective

To report the long-term safety and outcomes of topical atropine for childhood myopia control.

Design, Setting, and Participants

This prospective, double-masked observational study of the Atropine for the Treatment of Myopia (ATOM) 1 and ATOM2 randomized clinical trials took place at 2 single centers and included adults reviewed in 2021 through 2022 from the ATOM1 study (atropine 1% vs placebo; 1999 through 2003) and the ATOM2 study (atropine 0.01% vs 0.1% vs 0.5%; 2006 through 2012).

Main Outcome Measures

Change in cycloplegic spherical equivalent (SE) with axial length (AL); incidence of ocular complications.

Results

Among the original 400 participants in each original cohort, the study team evaluated 71 of 400 ATOM1 adult participants (17.8% of original cohort; study age, mean [SD] 30.5 [1.2] years; 40.6% female) and 158 of 400 ATOM2 adult participants (39.5% of original cohort; study age, mean [SD], 24.5 [1.5] years; 42.9% female) whose baseline characteristics (SE and AL) were representative of the original cohort. In this study, evaluating ATOM1 participants, the mean (SD) SE and AL were -5.20 (2.46) diopters (D), 25.87 (1.23) mm and -6.00 (1.63) D, 25.90 (1.21) mm in the 1% atropine-treated and placebo groups, respectively (difference of SE, 0.80 D; 95% CI, -0.25 to 1.85 D; P = .13; difference of AL, -0.03 mm; 95% CI, -0.65 to 0.58 mm; P = .92). In ATOM2 participants, the mean (SD) SE and AL was -6.40 (2.21) D; 26.25 (1.34) mm; -6.81 (1.92) D, 26.28 (0.99) mm; and -7.19 (2.87) D, 26.31 (1.31) mm in the 0.01%, 0.1%, and 0.5% atropine groups, respectively. There was no difference in the 20-year incidence of cataract/lens opacities, myopic macular degeneration, or parapapillary atrophy (β/γ zone) comparing the 1% atropine-treated group vs the placebo group.

Conclusions and Relevance

Among approximately one-quarter of the original participants, use of short-term topical atropine eye drops ranging from 0.01% to 1.0% for a duration of 2 to 4 years during childhood was not associated with differences in final refractive errors 10 to 20 years after treatment. There was no increased incidence of treatment or myopia-related ocular complications in the 1% atropine-treated group vs the placebo group. These findings may affect the design of future clinical trials, as further studies are required to investigate the duration and concentration of atropine for childhood myopia control.

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.

Predictors of myopic macular degeneration in a 12-year longitudinal study of Singapore adults with myopia

PURPOSE

To investigate the predictive factors for myopic macular degeneration (MMD) and progression in adults with myopia.

METHODS

We examined 828 Malay and Indian adults (1579 myopic eyes) with myopia (spherical equivalent (SE) ≤-0.5 dioptres) at baseline who participated in both baseline and 12-year follow-up visits of the Singapore Malay Eye Study and the Singapore Indian Eye Study. Eye examinations, including subjective refraction and axial length (AL) measurements, were performed. MMD was graded from fundus photographs following the Meta-Analysis for Pathologic Myopia classification. The predictive factors for MMD development and progression were assessed in adults without and with MMD at baseline, respectively as risk ratios (RR) using multivariable modified Poisson regression models. The receiver operating characteristic curve was used to visualise the performance of the predictive models for the development of MMD, with performance quantified by the area under the curve (AUC).

RESULTS

The 12-year cumulative MMD incidence was 10.3% (95% CI 8.9% to 12.0%) among 1504 myopic eyes without MMD at baseline. Tessellated fundus was a major predictor of MMD (RR=2.50, p<0.001), among other factors including age, worse SE and longer AL (all p<0.001). The AUC for prediction of MMD development was found to be 0.78 (95% CI 0.76 to 0.80) for tessellated fundus and increased significantly to an AUC of 0.86 (95% CI 0.84 to 0.88) with the combination of tessellated fundus with age, race, gender and SE (p<0.001). Older age (p=0.02), worse SE (p<0.001) and longer AL (p<0.001) were found to be predictors of MMD progression.

CONCLUSIONS

In adults with myopia without MMD, tessellated fundus, age, SE and AL had good predictive value for incident MMD. In adults with MMD, 1 in 10 eyes experienced progression over the same period. Older age, more severe myopia and longer AL were independent risk factors for progression.

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.

Posterior scleral birefringence measured by triple-input polarization-sensitive imaging as a biomarker of myopia progression

In myopic eyes, pathological remodelling of collagen in the posterior sclera has mostly been observed ex vivo. Here we report the development of triple-input polarization-sensitive optical coherence tomography (OCT) for measuring posterior scleral birefringence. In guinea pigs and humans, the technique offers superior imaging sensitivities and accuracies than dual-input polarization-sensitive OCT. In 8-week-long studies with young guinea pigs, scleral birefringence was positively correlated with spherical equivalent refractive errors and predicted the onset of myopia. In a cross-sectional study involving adult individuals, scleral birefringence was associated with myopia status and negatively correlated with refractive errors. Triple-input polarization-sensitive OCT may help establish posterior scleral birefringence as a non-invasive biomarker for assessing the progression of myopia.

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.

Rare variant analyses across multiethnic cohorts identify novel genes for refractive error

Refractive error, measured here as mean spherical equivalent (SER), is a complex eye condition caused by both genetic and environmental factors. Individuals with strong positive or negative values of SER require spectacles or other approaches for vision correction. Common genetic risk factors have been identified by genome-wide association studies (GWAS), but a great part of the refractive error heritability is still missing. Some of this heritability may be explained by rare variants (minor allele frequency [MAF] ≤ 0.01.). We performed multiple gene-based association tests of mean Spherical Equivalent with rare variants in exome array data from the Consortium for Refractive Error and Myopia (CREAM). The dataset consisted of over 27,000 total subjects from five cohorts of Indo-European and Eastern Asian ethnicity. We identified 129 unique genes associated with refractive error, many of which were replicated in multiple cohorts. Our best novel candidates included the retina expressed PDCD6IP, the circadian rhythm gene PER3, and P4HTM, which affects eye morphology. Future work will include functional studies and validation. Identification of genes contributing to refractive error and future understanding of their function may lead to better treatment and prevention of refractive errors, which themselves are important risk factors for various blinding conditions.

Development and Validation of a Model to Predict Who Will Develop Myopia in the Following Year as a Criterion to Define Premyopia

PURPOSE

To develop and validate models to predict who will develop myopia in the following year based on cycloplegic refraction or ocular biometry and to identify thresholds of premyopia.

METHODS

Prospective longitudinal data of nonmyopic children at baseline from the Guangzhou Twins Eye Study and the Guangzhou Outdoor Activity Longitudinal Study were used as the training set, and the Singapore Cohort Study of the Risk factors for Myopia study formed the external validation set. Age, sex, cycloplegic refraction, ocular biometry, uncorrected visual acuity, and parental myopia were integrated into 3 logistic regression models to predict the onset of myopia in the following year. Premyopia cutoffs and an integer risk score system were derived based on the identified risk.

RESULTS

In total, 2896 subjects with at least 2 visits were included. Cycloplegic refraction at baseline is a better predictor to identify the children with myopia onset [C-statistic=0.91, 95% confidence interval (CI), 0.87-0.94; C-statistic=0.92, 95% CI, 0.92-0.92 for internal and external validation, respectively], comparing to axial length, corneal curvature radius (CR) and anterior chamber depth (C-statistic=0.81, 95% CI, 0.73-0.88; C-statistic=0.80, 95% CI, 0.79-0.80, respectively), and axial length/CR (C-statistic=0.78, 95% CI, 0.71-0.85; C-statistic=0.76, 95% CI, 0.75-0.76). With a risk of >70%, the definitions of premyopia indicating approaching myopia onset were 0.00 D for 6-8 years and -0.25 D for ≥9 years in children with 2 myopic parents.

CONCLUSIONS

Either cycloplegic refraction or ocular biometry can predict 1-year risk of myopia. Premyopia can be successfully defined through risk assessments based on children's age and predict who would require more aggressive myopia prophylaxis.

Association of time outdoors and patterns of light exposure with myopia in children

BACKGROUND/AIMS

To evaluate the association of reported time outdoors and light exposure patterns with myopia among children aged 9 years from the Growing Up in Singapore Towards Healthy Outcomes birth cohort.

METHODS

We assessed reported time outdoors (min/day), light exposure patterns and outdoor activities of children aged 9 years (n=483) with a questionnaire, the FitSight watch and a 7-day activity diary. Light levels, the duration, timing and frequency of light exposure were assessed. Cycloplegic spherical equivalent (SE), myopia (SE≤-0.5 D) and axial length (AL) of paired eyes were analysed using generalised estimating equations.

RESULTS

In this study, 483 (966 eyes) multiethnic children (50.0% boys, 59.8% Chinese, 42.2% myopic) were included. Reported time outdoors (mean±SD) was 100±93 min/day, and average light levels were 458±228 lux. Of the total duration children spent at light levels of ≥1000 lux (37±19 min/day), 76% were spent below 5000 lux. Peak light exposure occurred at mid-day. Children had 1.7±1.0 light exposure episodes/day. Common outdoor activities were walks, neighbourhood play and swimming. Greater reported time outdoors was associated with lower odds of myopia (OR=0.82, 95% CI 0.70 to 0.95/hour increase daily; p=0.009). Light levels, timing and frequency of light exposures were not associated with myopia, SE or AL (p>0.05).

CONCLUSION

Reported time outdoors, light levels and number of light exposure episodes were low among Singaporean children aged 9 years. Reported time outdoors was protective against myopia but not light levels or specific light measures. A multipronged approach to increase time outdoors is recommended in the combat against the myopia epidemic.

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.

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.

Recovery From Form-Deprivation Myopia in Chicks Is Dependent Upon the Fullness and Correlated Color Temperature of the Light Spectrum

Purpose

The purpose of this study was to evaluate the impact of full-spectrum light-emitting diodes mimicking sunlight (Sunlike LEDs) on ocular growth and refractive error development in a chicken model of myopia.

Methods

One-day old chicks (n = 39) were distributed into 3 groups and raised for 28 days in isoluminant (approximately 285 lux) fluorescent (n = 18, [FL-4000], correlated color temperature [CCT] = 4000 K) or Sunlike LED (n = 12, [SL-4000], CCT = 4000 K; n = 9, [SL-6500], CCT = 6500 K) white lighting environments. Form-deprivation myopia was induced monocularly from day 1 post-hatching (D1) until D14. On D14, form deprivation was halted and the recovery of form-deprived (FD) eyes was monitored until D28. Axial length (AL), refraction, choroidal thickness, and anterior chamber depth were measured in vivo on D1, D7, D14, D22, and D28. Differences in outcome measures between eyes and groups were compared using 2-way repeated-measures ANOVA.

Results

AL and myopic refraction of FD eyes increased similarly among groups during form-deprivation. FD eyes of animals raised under SL-4000 (D22: P < 0.001 and D28: P < 0.001) and SL-6500 (D22: P = 0.006 and D28: P < 0.001) recovered faster from axial elongation compared with animals raised under FL-4000. The refractive status of FD eyes reared under SL-6500, not under FL-4000 or SL-4000, was similar to control eyes on D28 (P > 0.05). However, SL-4000 and SL-6500 exhibited similar refraction on D28 than FL-4000 (P > 0.05). Choroidal thickness was significantly greater in FD eyes of chickens raised under SL-6500 than in animals raised under FL-4000 (P = 0.03).

Conclusions

Compared to fluorescent light, moderate intensities of full-spectrum Sunlike LEDs can accelerate recovery from form-deprivation myopia in chickens, potentially through a change in the choroid-mediated pathway.

Incidence and Progression of Myopia in Early Adulthood

IMPORTANCE

Myopia incidence and progression has been described extensively in children. However, few data exist regarding myopia incidence and progression in early adulthood.

OBJECTIVE

To describe the 8-year incidence of myopia and change in ocular biometry in young adults and their association with the known risk factors for childhood myopia.

DESIGN, SETTING, AND PARTICIPANTS

The Raine Study is a prospective single-center cohort study. Baseline and follow-up eye assessments were conducted from January 2010 to August 2012 and from March 2018 to March 2020. The data were analyzed from June to July 2021. A total of 1328 participants attended the baseline assessment, and 813 participants attended the follow-up assessment. Refractive information from both visits was available for 701 participants. Participants with keratoconus, previous corneal surgery, or recent orthokeratology wear were excluded.

EXPOSURES

Participants' eyes were examined at ages 20 years (baseline) and 28 years.

MAIN OUTCOMES AND MEASURES

Incidence of myopia and high myopia; change in spherical equivalent (SE) and axial length (AL).

RESULTS

A total of 516 (261 male [50.6%]) and 698 (349 male [50.0%]) participants without myopia or high myopia at baseline, respectively, were included in the incidences analyses, while 691 participants (339 male [49%]) were included in the progression analysis. The 8-year myopia and high myopia incidence were 14.0% (95% CI, 11.5%-17.4%) and 0.7% (95% CI, 0.3%-1.2%), respectively. A myopic shift (of 0.50 diopters [D] or greater in at least 1 eye) occurred in 261 participants (37.8%). Statistical significance was found in longitudinal changes in SE (-0.04 D per year; P < .001), AL (0.02 mm per year; P <.001), and lens thickness (0.02 mm per year; P < .001). Incident myopia was associated with self-reported East Asian vs White race (odds ratio [OR], 6.13; 95% CI, 1.06-35.25; P = .04), female vs male sex (OR, 1.81; 95% CI, 1.02-3.22; P = .04), smaller conjunctival ultraviolet autofluorescence area (per 10-mm2 decrease, indicating less sun exposure; OR, 9.86; 95% CI, 9.76-9.97; P = <.009), and parental myopia (per parent; OR, 1.57; 95% CI, 1.03-2.38; P = <.05). Rates of myopia progression and axial elongation were faster in female participants (estimate: SE, 0.02 D per year; 95 % CI, 0.01-0.02 and AL, 0.007 mm per year, 95 % CI, 0.00.-0.011; P ≤ .001) and those with parental myopia (estimate per parent: SE, 0.01 D per year; 95% CI, 0.00-0.02 and AL, 95% CI, 0.002-0.008; P ≤ .001). Education level was not associated with myopia incidence or progression.

CONCLUSIONS AND RELEVANCE

These findings suggest myopia progression continues for more than one-third of adults during the third decade of life, albeit at lower rates than during childhood. The protective effects of time outdoors against myopia may continue into young adulthood.

Cost of Myopia Correction: A Systematic Review

Myopia is one of the leading causes of visual impairment globally. Despite increasing prevalence and incidence, the associated cost of treatment remains unclear. Health care spending is a major concern in many countries and understanding the cost of myopia correction is the first step eluding to the overall cost of myopia treatment. As cost of treatment will reduce the burden of cost of illness, this will aid in future cost-benefit analysis and the allocation of healthcare resources, including considerations in integrating eye care (refractive correction with spectacles) into universal health coverage (UHC). We performed a systematic review to determine the economic costs of myopia correction. However, there were few studies for direct comparison. Costs related to myopia correction were mainly direct with few indirect costs. Annual prevalence-based direct costs for myopia ranged from $14-26 (USA), $56 (Iran) and $199 (Singapore) per capita, respectively (population: 274.63 million, 75.15 million and 3.79 million, respectively). Annually, the direct costs of contact lens were $198.30-$378.10 while spectacles and refractive surgeries were $342.50 and $19.10, respectively. This review provides an insight to the cost of myopia correction. Myopia costs are high from nation-wide perspectives because of the high prevalence of myopia, with contact lenses being the more expensive option. Without further interventions, the burden of illness of myopia will increase substantially with the projected increase in prevalence worldwide. Future studies will be necessary to generate more homogenous cost data and provide a complete picture of the global economic cost of myopia.

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.

Multi-task learning approach for volumetric segmentation and reconstruction in 3D OCT images

The choroid is the vascular layer of the eye that supplies photoreceptors with oxygen. Changes in the choroid are associated with many pathologies including myopia where the choroid progressively thins due to axial elongation. To quantize these changes, there is a need to automatically and accurately segment the choroidal layer from optical coherence tomography (OCT) images. In this paper, we propose a multi-task learning approach to segment the choroid from three-dimensional OCT images. Our proposed architecture aggregates the spatial context from adjacent cross-sectional slices to reconstruct the central slice. Spatial context learned by this reconstruction mechanism is then fused with a U-Net based architecture for segmentation. The proposed approach was evaluated on volumetric OCT scans of 166 myopic eyes acquired with a commercial OCT system, and achieved a cross-validation Intersection over Union (IoU) score of 94.69% which significantly outperformed (p<0.001) the other state-of-the-art methods on the same data set. Choroidal thickness maps generated by our approach also achieved a better structural similarity index (SSIM) of 72.11% with respect to the groundtruth. In particular, our approach performs well for highly challenging eyes with thinner choroids. Compared to other methods, our proposed approach also requires lesser processing time and has lower computational requirements. The results suggest that our proposed approach could potentially be used as a fast and reliable method for automated choroidal segmentation.

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.

A Web-Based Time-Use Application to Assess Diet and Movement Behavior in Asian Schoolchildren: Development and Usability Study of My E-Diary for Activities and Lifestyle (MEDAL)

Background

Web-based time-use diaries for schoolchildren are limited, and existing studies focus mostly on capturing physical activities and sedentary behaviors but less comprehensively on dietary behaviors.

Objective

This study aims to describe the development of My E-Diary for Activities and Lifestyle (MEDAL)—a self-administered, web-based time-use application to assess diet and movement behavior—and to evaluate its usability in schoolchildren in Singapore.

Methods

MEDAL was developed through formative research and an iterative user-centric design approach involving small groups of schoolchildren (ranging from n=5 to n=15, aged 7-13 years). To test the usability, children aged 10-11 years were recruited from 2 primary schools in Singapore to complete MEDAL for 2 weekdays and 2 weekend days and complete a 10-item usability questionnaire.

Results

The development process revealed that younger children (aged <9 years) were less able to complete MEDAL independently. Of the 204 participants (118/204, 57.8% boys, and 31/201, 15.4% overweight) in the usability study, 57.8% (118/204) completed 3 to 4 days of recording, whereas the rest recorded for 2 days or less. The median time taken to complete MEDAL was 14.2 minutes per day. The majority of participants agreed that instructions were clear (193/203, 95.1%), that MEDAL was easy to use (173/203, 85.2%), that they liked the application (172/202, 85.1%), and that they preferred recording their activities on the web than on paper (167/202, 82.7%). Among all the factors evaluated, recording for 4 days was the least satisfactory component reported. Compared with boys, girls reported better recall ability and agreed that the time spent on completing 1-day entry was appropriate.

Conclusions

MEDAL appears to be a feasible application to capture diet and movement behaviors in children aged 10-12 years, particularly in the Asian context. Some gender differences in usability performance were observed, but the majority of the participants had a positive experience using MEDAL. The validation of the data collected through the application is in progress.

Assessment of the Macular Microvasculature in High Myopes With Swept Source Optical Coherence Tomographic Angiography

Background: The risk of pathologic myopia (PM) increases with worsening myopia and may be related to retinal microvasculature alterations. To evaluate this, we analyzed the macular microvasculature of myopes with swept source-optical coherence tomographic angiography (SS-OCTA) in adolescent and young adult Singaporeans.

Methods: This is a prevalent case-control study including 93 young Chinese from the Strabismus, Amblyopia and Refractive error in Singaporean children (STARS, N = 45) study and the Singapore Cohort Study of Risk Factors for Myopia (SCORM, N = 48) studies. Macular vessel density (VD) measurements were obtained from 3 × 3 mm SS-OCTA scans and independently assessed using ImageJ. These measurements were compared between individuals with non-high myopia [non-HM, N = 40; SE >-5.0 diopter (D)] and HM (SE ≤-5.0D, N = 53).

Results: The mean macular VD was 40.9 ± 0.6% and 38.2 ± 0.5% in the non-HM and HM, groups, respectively (p = 0.01 adjusted for age and gender). Mean FAZ area in the superficial layer was 0.22 ± 0.02 mm² in the HM group, which was smaller compared to non-HM group (0.32 ± 0.03 mm², p = 0.04). Mean deep FAZ area was similar between the two groups (0.45 ± 0.03 mm² and 0.48 ± 0.04 mm² in the HM and non-HM groups, respectively, p = 0.70).

Conclusions: VD was lower and superficial FAZ area was smaller, in adolescents and young adults with HM compared to non-HM. These findings require validation in prospective studies to assess their impact on the subsequent development of PM.

Retinal photograph-based deep learning algorithms for myopia and a blockchain platform to facilitate artificial intelligence medical research: a retrospective multicohort study

BACKGROUND

By 2050, almost 5 billion people globally are projected to have myopia, of whom 20% are likely to have high myopia with clinically significant risk of sight-threatening complications such as myopic macular degeneration. These are diagnoses that typically require specialist assessment or measurement with multiple unconnected pieces of equipment. Artificial intelligence (AI) approaches might be effective for risk stratification and to identify individuals at highest risk of visual loss. However, unresolved challenges for AI medical studies remain, including paucity of transparency, auditability, and traceability.

METHODS

In this retrospective multicohort study, we developed and tested retinal photograph-based deep learning algorithms for detection of myopic macular degeneration and high myopia, using a total of 226 686 retinal images. First we trained and internally validated the algorithms on datasets from Singapore, and then externally tested them on datasets from China, Taiwan, India, Russia, and the UK. We also compared the performance of the deep learning algorithms against six human experts in the grading of a randomly selected dataset of 400 images from the external datasets. As proof of concept, we used a blockchain-based AI platform to demonstrate the real-world application of secure data transfer, model transfer, and model testing across three sites in Singapore and China.

FINDINGS

The deep learning algorithms showed robust diagnostic performance with areas under the receiver operating characteristic curves [AUC] of 0·969 (95% CI 0·959-0·977) or higher for myopic macular degeneration and 0·913 (0·906-0·920) or higher for high myopia across the external testing datasets with available data. In the randomly selected dataset, the deep learning algorithms outperformed all six expert graders in detection of each condition (AUC of 0·978 [0·957-0·994] for myopic macular degeneration and 0·973 [0·941-0·995] for high myopia). We also successfully used blockchain technology for data transfer, model transfer, and model testing between sites and across two countries.

INTERPRETATION

Deep learning algorithms can be effective tools for risk stratification and screening of myopic macular degeneration and high myopia among the large global population with myopia. The blockchain platform developed here could potentially serve as a trusted platform for performance testing of future AI models in medicine.

FUNDING

None.

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.

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.

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.

Visual field defects and myopic macular degeneration in Singapore adults with high myopia

AIMS

To characterise the association between visual field (VF) defects and myopic macular degeneration (MMD) in highly myopic adults without glaucoma.

METHODS

Participants (n=106; 181 eyes) with high myopia (HM; spherical equivalent ≤-5.0 D or axial length (AL) ≥26 mm), after excluding glaucoma and glaucoma suspects, from the Singapore Epidemiology of Eye Diseases-HM study were included in this cross-sectional study. Humphrey VF (central 24-2 threshold), cup-disc ratio (CDR) and intraocular pressure (IOP) measurements were performed. Mean deviation (MD) and pattern SD (PSD), VF defects (normal or abnormal; p<0.05 in ≥3 non-edge contiguous locations) and pattern (eg, generalised sensitivity loss) were analysed. MMD presence was diagnosed from fundus photographs. Generalised estimating equations were used for analysing factors (MD, PSD, VF defects, CDR and IOP) associated with MMD.

RESULTS

Mean age was 55.4±9.9 years and 51.9% were women (AL=26.7±1.1 mm). MMD eyes had lower MD (-3.8±2.9 dB vs -1.1±1.4 dB) and higher PSD (2.8±1.7 dB vs 1.7±0.6 dB). A higher percentage of MMD eyes (n=48) had abnormal VF (62.5% vs 28.6%; p<0.001) compared with no MMD (n=133 eyes). VF pattern in MMD eyes was significantly different from eyes without MMD (p=0.001) with greater generalised sensitivity loss (53.3% vs 10.5%) and arcuate defects (16.7% vs 10.5%). In multivariate analyses, MD (OR=1.52) and PSD (OR=1.67) were significantly (p=0.003) associated with MMD, but VF defects were not associated with MMD.

CONCLUSION

Highly myopic adults with MMD may have VF loss when compared with highly myopic patients without MMD even in adults without glaucoma.

A synopsis of the prevalence rates and environmental risk factors for myopia

The prevalence rates of myopia are higher in urban Asian cities such as Hong Kong and Singapore. One observation over the past few decades is that the prevalence rates of myopia have been rising and there is an epidemic of myopia in Asia. The age-old question of the roles of nature and nurture in this process remains unanswered. The strongest evidence for an environmental link to myopia is near work activity. Childhood exposure to night lighting has also been explored in different studies but the results have been mixed. Twin studies, segregation analysis and association studies have demonstrated that hereditary factors play an important role in myopia development. The exact nature and interplay of genetic and environmental factors is not known and data suggest that environmental factors may interact with genetic factors to increase the risks of developing myopia. Future research is needed to identify specific modifiable lifestyle factors and genetic markers for myopia. This will enable preventive measures such as health education to be instituted.

Deep Learning Approach for Automated Detection of Myopic Maculopathy and Pathologic Myopia in Fundus Images

PURPOSE

To determine whether eyes with pathologic myopia can be identified and whether each type of myopic maculopathy lesion on fundus photographs can be diagnosed by deep learning (DL) algorithms.

DESIGN

A DL algorithm was developed to recognize myopic maculopathy features and to categorize the myopic maculopathy automatically.

PARTICIPANTS

We examined 7020 fundus images from 4432 highly myopic eyes obtained from the Advanced Clinical Center for Myopia.

METHODS

Deep learning (DL) algorithms were developed to recognize the key features of myopic maculopathy with 5176 fundus images. These algorithms were also used to develop a Meta-analysis for Pathologic Myopia (META-PM) study categorizing system (CS) by adding a specific processing layer. Models and the system were evaluated by 1844 fundus image. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were used to determine the performance of each DL algorithm. The rate of correct predictions was used to determine the performance of the META-PM study CS.

MAIN OUTCOME MEASURES

Four trained DL models were able to recognize the lesions of myopic maculopathy accurately with high sensitivity and specificity. The META-PM study CS also showed a high accuracy and was qualified to be used in a semiautomated way during screening for myopic maculopathy in highly myopic eyes.

RESULTS

The sensitivity of the DL models was 84.44% for diffuse atrophy, 87.22% for patchy atrophy, 85.10% for macular atrophy, and 37.07% for choroidal neovascularization, and the AUC values were 0.970, 0.978, 0.982, and 0.881, respectively. The rate of total correct predictions from the META-PM study CS was 87.53%, with rates of 90.18%, 95.28%, 97.50%, and 91.14%, respectively, for each type of lesion. The META-PM study CS showed an overall rate of 92.08% in detecting pathologic myopia correctly, which was defined as having myopic maculopathy equal to or more serious than diffuse atrophy.

CONCLUSIONS

The novel DL models and system can achieve high sensitivity and specificity in identifying the different types of lesions of myopic maculopathy. These results will assist in the screening for pathologic myopia and subsequent protection of patients against low vision and blindness caused by myopic maculopathy.

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

Importance

Parental myopia is an important risk factor for preschool myopia in Asian children. Further investigation of the association between parental myopia and early-onset myopia risk in other racial/ethnic groups, such as African American and Hispanic white children, could improve understanding of the etiology and treatment of this condition.

Objective

To investigate the association of parental myopia with refractive error and ocular biometry in multiethnic children aged 6 to 72 months.

Design, Setting, and Participants

This cohort study pooled data from children in 3 population-based studies with comparable design from the US, Singapore, and Australia. Parental myopia was defined as the use of glasses or contact lenses for distance viewing by the child's biological parent(s). Multivariable regressions were conducted to assess the association of parental myopia. Data were collected from 2003 to 2011 and analyzed from 2017 to 2019.

Main Outcomes and Measures

Cycloplegic refraction and prevalence of myopia (spherical equivalent refractive error of≤-0.5 diopters [D]) in the more myopic eye.

Results

The analysis cohort included 9793 children, including 4003 Asian, 2201 African American, 1998 Hispanic white, and 1591 non-Hispanic white participants (5106 boys [52.1%]; mean [SD] age, 40.0 [18.9] months). Compared with children without parental myopia, the odds ratios for early-onset myopia were 1.42 (95% CI, 1.20-1.68) for children with 1 parent with myopia, 2.70 (95% CI, 2.19-3.33) for children with 2 parents with myopia, and 3.39 (95% CI, 1.99-5.78) for children with 2 parents with childhood-onset myopia. Even among children without myopia, parental myopia was associated with a greater ratio of axial length to corneal curvature radius (regression coefficient for myopia in both parents, 0.023; P < .001) and more myopic refractive error (regression coefficient for myopia in both parents, -0.20 D; P < .001). Effects of parental myopia were observed in all 4 racial/ethnic groups and across age groups except those younger than 1 year. However, parental myopia was not associated with the age-related trends of refractive error (regression coefficient for children without parental myopeia, 0.08; for children with 2 parents with myopia, 0.04; P = .31 for interaction) and ratio of axial length to corneal curvature radius (regression coefficient for children without parental myopeia, 0.031; for children with 2 parents with myopia, 0.032; P = .89 for interaction) beyond infancy.

Conclusions and Relevance

Parental myopia, especially childhood-onset parental myopia, was associated with a greater risk of early-onset myopia in Asian, Hispanic, non-Hispanic white, and African American children. The observed associations of parental myopia in children as early as 1 year of age and in children without myopia suggests that genetic susceptibility may play a more important role in early-onset myopia and that parental myopia may contribute to myopia in children by setting up a more myopic baseline before school age.

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.

Six-Year Changes in Myopic Macular Degeneration in Adults of the Singapore Epidemiology of Eye Diseases Study

Purpose

To examine the 6-year incidence, progression, associated risk factors, and impact of myopic macular degeneration (MMD) in a myopic population in Singapore.

Methods

We examined myopic (spherical equivalent ≤-0.5 diopters) adults (N = 2157 persons and 3661 eyes) who were phakic at baseline and participated in both baseline and 6-year follow-up visits of the Singapore Epidemiology of Eye Diseases study. Eye examinations, including visual acuity, subjective refraction and axial length (AL) measurements, were performed. MMD was graded from fundus photographs following the META-PM classification. Vision-related quality of life was assessed with Rasch-transformed scores from reading, mobility, and emotional domains of the Impact of Vision Impairment questionnaire.

Results

The 6-year eye-specific incidence of MMD among myopic eyes was 1.2% (95% CI, 0.9%-1.6%). Older age, worse spherical equivalent, and longer AL at baseline were associated with MMD incidence (all P < 0.001). The 6-year eye-specific progression of MMD in 288 eyes with baseline MMD was 17.0% (95% CI, 12.6%-21.4%). More severe MMD at baseline, worse spherical equivalent, and longer AL (all P < 0.05) were associated with MMD progression. Patients with Meta-PM categories 3 and 4 had worse best-corrected visual acuity and poorer vision-related quality of life outcomes than those without MMD (all P < 0.05).

Conclusions

Over a 6-year period, one in 80 myopic eyes developed MMD and one in six with existing MMD had MMD progression. Myopia severity and AL were strong predictors of MMD development and progression. Eyes with severe MMD were at higher risk of MMD progression than those with less severe MMD, and were associated with poorer visual acuity and vision-related quality of life.

Highlights from the 2019 International Myopia Summit on 'controversies in myopia'

Myopia is an emerging public health issue with potentially significant economic and social impact, especially in East Asia. However, many uncertainties about myopia and its clinical management remain. The International Myopia Summit workgroup was convened by the Singapore Eye Research Institute, the WHO Regional Office for the Western Pacific and the International Agency for the Prevention of Blindness in 2019. The aim of this workgroup was to summarise available evidence, identify gaps or unmet needs and provide consensus on future directions for clinical research in myopia. In this review, among the many 'controversies in myopia' discussed, we highlight three main areas of consensus. First, development of interventions for the prevention of axial elongation and pathologic myopia is needed, which may require a multifaceted approach targeting the Bruch's membrane, choroid and/or sclera. Second, clinical myopia management requires co-operation between optometrists and ophthalmologists to provide patients with holistic care and a tailored approach that balances risks and benefits of treatment by using optical and pharmacological interventions. Third, current diagnostic technologies to detect myopic complications may be improved through collaboration between clinicians, researchers and industry. There is an unmet need to develop new imaging modalities for both structural and functional analyses and to establish normative databases for myopic eyes. In conclusion, the workgroup's call to action advocated for a paradigm shift towards a collaborative approach in the holistic clinical management of myopia.

Volumetric Choroidal Segmentation Using Sequential Deep Learning Approach in High Myopia Subjects

Many ocular diseases are associated with choroidal changes. Therefore, it is crucial to be able to segment the choroid to study its properties. Previous methods for choroidal segmentation have focused on single cross-sectional scans. Volumetric choroidal segmentation has yet to be widely reported. In this paper, we propose a sequential segmentation approach using a variation of U-Net with a bidirectional C-LSTM(Convolutional Long Short Term Memory) module in the bottleneck region. The model is evaluated on volumetric scans from 40 high myopia subjects, obtained using SS-OCT(Swept Source Optical Coherence Tomography). A comparison with other U-Net-based variants is also presented. The results demonstrate that volumetric segmentation of the choroid can be achieved with an accuracy of IoU(Intersection over Union) 0.92.Clinical relevance- This deep learning approach can automatically segment the choroidal volume, which can enable better evaluation and monitoring at ocular diseases.

Genome-Wide Association Study in Asians Identifies Novel Loci for High Myopia and Highlights a Nervous System Role in Its Pathogenesis

PURPOSE

To identify novel susceptibility loci for high myopia.

DESIGN

Genome-wide association study (GWAS) followed by replication and meta-analysis.

PARTICIPANTS

A total of 14 096 samples from East and Southeast Asian populations (2549 patients with high myopia and 11 547 healthy controls).

METHODS

We performed a GWAS in 3269 Japanese individuals (1668 with high myopia and 1601 control participants), followed by replication analysis in a total of 10 827 additional samples (881 with high myopia and 9946 control participants) from Japan, Singapore, and Taiwan. To confirm the biological role of the identified loci in the pathogenesis of high myopia, we performed functional annotation and Gene Ontology (GO) analyses.

MAIN OUTCOME MEASURES

We evaluated the association of single nucleotide polymorphisms with high myopia and GO terms enriched among genes identified in the current study.

RESULTS

We identified 9 loci with genome-wide significance (P < 5.0 × 10^-8). Three loci were previously reported myopia-related loci (ZC3H11B on 1q41, GJD2 on 15q14, and RASGRF1 on 15q25.1), and the other 6 were novel (HIVEP3 on 1p34.2, NFASC/CNTN2 on 1q32.1, CNTN4/CNTN6 on 3p26.3, FRMD4B on 3p14.1, LINC02418 on 12q24.33, and AKAP13 on 15q25.3). The GO analysis revealed a significant role of the nervous system related to synaptic signaling, neuronal development, and Ras/Rho signaling in the pathogenesis of high myopia.

CONCLUSIONS

The current study identified 6 novel loci associated with high myopia and demonstrated an important role of the nervous system in the disease pathogenesis. Our findings give new insight into the genetic factors underlying myopia, including high myopia, by connecting previous findings and allowing for a clarified interpretation of the cause and pathophysiologic features of myopia at the molecular level.

Mendelian randomization analysis does not support causal associations of birth weight with hypertension risk and blood pressure in adulthood

Epidemiology studies suggested that low birthweight was associated with a higher risk of hypertension in later life. However, little is known about the causality of such associations. In our study, we evaluated the causal association of low birthweight with adulthood hypertension following a standard analytic protocol using the study-level data of 183,433 participants from 60 studies (CHARGE-BIG consortium), as well as that with blood pressure using publicly available summary-level genome-wide association data from EGG consortium of 153,781 participants, ICBP consortium and UK Biobank cohort together of 757,601 participants. We used seven SNPs as the instrumental variable in the study-level analysis and 47 SNPs in the summary-level analysis. In the study-level analyses, decreased birthweight was associated with a higher risk of hypertension in adults (the odds ratio per 1 standard deviation (SD) lower birthweight, 1.22; 95% CI 1.16 to 1.28), while no association was found between genetically instrumented birthweight and hypertension risk (instrumental odds ratio for causal effect per 1 SD lower birthweight, 0.97; 95% CI 0.68 to 1.41). Such results were consistent with that from the summary-level analyses, where the genetically determined low birthweight was not associated with blood pressure measurements either. One SD lower genetically determined birthweight was not associated with systolic blood pressure (β = - 0.76, 95% CI - 2.45 to 1.08 mmHg), 0.06 mmHg lower diastolic blood pressure (β = - 0.06, 95% CI - 0.93 to 0.87 mmHg), or pulse pressure (β = - 0.65, 95% CI - 1.38 to 0.69 mmHg, all p > 0.05). Our findings suggest that the inverse association of birthweight with hypertension risk from observational studies was not supported by large Mendelian randomization analyses.

Caries Risk Prediction Models in a Medical Health Care Setting

Despite development of new technologies for caries control, tooth decay in primary teeth remains a major global health problem. Caries risk assessment (CRA) models for toddlers and preschoolers are rare. Among them, almost all models use dental factors (e.g., past caries experience) to predict future caries risk, with limited clinical/community applicability owing to relatively uncommon dental visits compared to frequent medical visits during the first year of life. The objective of this study was to construct and evaluate risk prediction models using information easily accessible to medical practitioners to forecast caries at 2 and 3 y of age. Data were obtained from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) mother-offspring cohort. Caries was diagnosed using modified International Caries Detection and Assessment System criteria. Risk prediction models were constructed using multivariable logistic regression coupled with receiver operating characteristic analyses. Imputation was performed using multiple imputation by chained equations to assess effect of missing data. Caries rates at ages 2 y (n = 535) and 3 y (n = 721) were 17.8% and 42.9%, respectively. Risk prediction models predicting overall caries risk at 2 and 3 y demonstrated area under the curve (AUC) (95% confidence interval) of 0.81 (0.75-0.87) and 0.79 (0.74-0.84), respectively, while those predicting moderate to extensive lesions showed 0.91 (0.85-0.97) and 0.79 (0.73-0.85), respectively. Postimputation results showed reduced AUC of 0.75 (0.74-0.81) and 0.71 (0.67-0.75) at years 2 and 3, respectively, for overall caries risk, while AUC was 0.84 (0.76-0.92) and 0.75 (0.70-0.80), respectively, for moderate to extensive caries. Addition of anterior caries significantly increased AUC in all year 3 models with or without imputation (all P < 0.05). Significant predictors/protectors were identified, including ethnicity, prenatal tobacco smoke exposure, history of allergies before 12 mo, history of chronic maternal illness, maternal brushing frequency, childbearing age, and so on. Integrating oral-general health care using medical CRA models may be promising in screening caries-susceptible infants/toddlers, especially when medical professionals are trained to "lift the lip" to identify anterior caries lesions.

Rationale and protocol for the 7- and 8-year longitudinal assessments of eye health in a cohort of young adults in the Raine Study

INTRODUCTION

Eye diseases and visual impairment more commonly affect elderly adults, thus, the majority of ophthalmic cohort studies have focused on older adults. Cohort studies on the ocular health of younger adults, on the other hand, have been few. The Raine Study is a longitudinal study that has been following a cohort since their birth in 1989-1991. As part of the 20-year follow-up of the Raine Study, participants underwent a comprehensive eye examination. As part of the 27- and 28-year follow-ups, eye assessments are being conducted and the data collected will be compared with those of the 20-year follow-up. This will provide an estimate of population incidence and updated prevalence of ocular conditions such as myopia and keratoconus, as well as longitudinal change in ocular parameters in young Australian adults. Additionally, the data will allow exploration of the environmental, health and genetic factors underlying inter-subject differential long-term ocular changes.

METHODS AND ANALYSIS

Participants are being contacted via telephone, email and/or social media and invited to participate in the eye examination. At the 27-year follow-up, participants completed a follow-up eye screening, which assessed visual acuity, autorefraction, ocular biometry and ocular sun exposure. Currently, at the 28-year follow-up, a comprehensive eye examination is being conducted which, in addition to all the eye tests performed at the 27-year follow-up visit, includes tonometry, optical coherence tomography, funduscopy and anterior segment topography, among others. Outcome measures include the incidence of refractive error and pterygium, an updated prevalence of these conditions, and the 8-year change in ocular parameters.

ETHICS AND DISSEMINATION

The Raine Study is registered in the Australian New Zealand Clinical Trials Registry. The Gen2 20-year, 27-year and 28-year follow-ups are approved by the Human Research Ethics Committee of the University of Western Australia. Findings resulting from the study will be published in health or medical journals and presented at conferences.

TRIAL REGISTRATION NUMBER

ACTRN12617001599369; Active, not recruiting.

A review on the epidemiology of myopia in school children worldwide

Background

Due to high prevalence myopia has gained importance in epidemiological studies. Children with early onset are at particular risk of complications associated with myopia, as progression over time might result in high myopia and myopic macular degeneration. Both genetic and environmental factors play a role in the increasing prevalence of myopia. The aim of this study is to review the current literature on epidemiology and risk factors for myopia in school children (aged 6–19 years) around the world.

Main body

PubMed and Medline were searched for the following keywords: prevalence, incidence, myopia, refractive error, risk factors, children and visual impairment. English language articles published between Jan 2013 and Mar 2019 were included in the study. Studies were critically reviewed for study methodology and robustness of data. Eighty studies were included in this literature review.

Myopia prevalence remains higher in Asia (60%) compared with Europe (40%) using cycloplegic refraction examinations. Studies reporting on non-cycloplegic measurements show exceptionally high myopia prevalence rates in school children in East Asia (73%), and high rates in North America (42%). Low prevalence under 10% was described in African and South American children. In recent studies, risk factors for myopia in schoolchildren included low outdoor time and near work, dim light exposure, the use of LED lamps for homework, low sleeping hours, reading distance less than 25 cm and living in an urban environment.

Conclusion

Low levels of outdoor activity and near work are well-established risk factors for myopia; this review provides evidence on additional environmental risk factors. New epidemiological studies should be carried out on implementation of public health strategies to tackle and avoid myopia. As the myopia prevalence rates in non-cycloplegic studies are overestimated, we recommend considering only cycloplegic measurements.

Axial Growth and Lens Power Loss at Myopia Onset in Singaporean Children

Purpose

We studied biometry changes before and after myopia onset in a cohort of Singaporean children.

Methods

All data were taken from the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). Participants underwent refraction and biometry measurements with a follow-up of 3 to 6 years. The longitudinal ocular biometry (spherical equivalent refraction, axial length, and lens power) changes were compared between children who suffered myopia during the study (N = 303), emmetropic children (N = 490), and children myopic at baseline (N = 509).

Results

At myopia onset, the myopic shift increased to 0.50 diopters (D)/y or more in new myopes compared to the minor changes in emmetropes of the same age. New myopes had higher axial growth rates than emmetropes, even years before myopia onset (0.37 and 0.14 mm/y, respectively; ANOVA with Bonferroni post hoc test, P < 0.001). After onset, the change in both parameters slowed down gradually, but significantly (P < 0.05). In new myopes, lens power loss (-0.71 D/y) was significantly higher up to 1 year before myopia onset compared to emmetropes (-0.46 D/y), after which lens power loss slows down rapidly. At age 7 years, (future) new myopes had lens power values close to those of emmetropes (25.12 and 25.23 D, respectively), while later these values approached those of children who were myopic at baseline (23.06 and 22.79 D, respectively, compared to 23.71 D for emmetropes; P < 0.001).

Conclusions

New myopes have higher axial growth rates and lens power loss before myopia onset than persistent emmetropes.

Behavioral Heterogeneity in Relation with Brain Functional Networks in Young Children

This study aimed to identify distinct behavioral profiles in a population-based sample of 654 4-year-old children and characterize their relationships with brain functional networks using resting-state functional magnetic resonance imaging data. Young children showed 7 behavioral profiles, including a super healthy behavioral profile with the lowest scores across all Child Behavior CheckList (CBCL) subscales (G1) and other 6 behavioral profiles, respectively with pronounced withdrawal (G2), somatic complaints (G3), anxiety and withdrawal (G4), somatic complaints and withdrawal (G5), the mixture of emotion, withdrawal, and aggression (G6), and attention (G7) problems. Compared with children in G1, children with withdrawal shared abnormal functional connectivities among the sensorimotor networks. Children in emotionally relevant problems shared the common pattern among the attentional and frontal networks. Nevertheless, children in sole withdrawal problems showed a unique pattern of connectivity alterations among the sensorimotor, cerebellar, and salience networks. Children with somatic complaints showed abnormal functional connectivities between the attentional and subcortical networks, and between the language and posterior default mode networks. This study provides novel evidence on the existence of behavioral heterogeneity in early childhood and its associations with specific functional networks that are clinically relevant phenotypes for mental illness and are apparent from early childhood.

A trans-ancestral meta-analysis of genome-wide association studies reveals loci associated with childhood obesity

Although hundreds of genome-wide association studies-implicated loci have been reported for adult obesity-related traits, less is known about the genetics specific for early-onset obesity and with only a few studies conducted in non-European populations to date. Searching for additional genetic variants associated with childhood obesity, we performed a trans-ancestral meta-analysis of 30 studies consisting of up to 13 005 cases (≥95th percentile of body mass index (BMI) achieved 2-18 years old) and 15 599 controls (consistently <50th percentile of BMI) of European, African, North/South American and East Asian ancestry. Suggestive loci were taken forward for replication in a sample of 1888 cases and 4689 controls from seven cohorts of European and North/South American ancestry. In addition to observing 18 previously implicated BMI or obesity loci, for both early and late onset, we uncovered one completely novel locus in this trans-ancestral analysis (nearest gene, METTL15). The variant was nominally associated with only the European subgroup analysis but had a consistent direction of effect in other ethnicities. We then utilized trans-ancestral Bayesian analysis to narrow down the location of the probable causal variant at each genome-wide significant signal. Of all the fine-mapped loci, we were able to narrow down the causative variant at four known loci to fewer than 10 single nucleotide polymorphisms (SNPs) (FAIM2, GNPDA2, MC4R and SEC16B loci). In conclusion, an ethnically diverse setting has enabled us to both identify an additional pediatric obesity locus and further fine-map existing loci.

IMI - Interventions Myopia Institute: Interventions for Controlling Myopia Onset and Progression Report

Myopia has been predicted to affect approximately 50% of the world's population based on trending myopia prevalence figures. Critical to minimizing the associated adverse visual consequences of complicating ocular pathologies are interventions to prevent or delay the onset of myopia, slow its progression, and to address the problem of mechanical instability of highly myopic eyes. Although treatment approaches are growing in number, evidence of treatment efficacy is variable. This article reviews research behind such interventions under four categories: optical, pharmacological, environmental (behavioral), and surgical. In summarizing the evidence of efficacy, results from randomized controlled trials have been given most weight, although such data are very limited for some treatments. The overall conclusion of this review is that there are multiple avenues for intervention worthy of exploration in all categories, although in the case of optical, pharmacological, and behavioral interventions for preventing or slowing progression of myopia, treatment efficacy at an individual level appears quite variable, with no one treatment being 100% effective in all patients. Further research is critical to understanding the factors underlying such variability and underlying mechanisms, to guide recommendations for combined treatments. There is also room for research into novel treatment options.

Genetic variants linked to myopic macular degeneration in persons with high myopia: CREAM Consortium

Purpose

To evaluate the roles of known myopia-associated genetic variants for development of myopic macular degeneration (MMD) in individuals with high myopia (HM), using case-control studies from the Consortium of Refractive Error and Myopia (CREAM).

Methods

A candidate gene approach tested 50 myopia-associated loci for association with HM and MMD, using meta-analyses of case-control studies comprising subjects of European and Asian ancestry aged 30 to 80 years from 10 studies. Fifty loci with the strongest associations with myopia were chosen from a previous published GWAS study. Highly myopic (spherical equivalent [SE] ≤ -5.0 diopters [D]) cases with MMD (N = 348), and two sets of controls were enrolled: (1) the first set included 16,275 emmetropes (SE ≤ -0.5 D); and (2) second set included 898 highly myopic subjects (SE ≤ -5.0 D) without MMD. MMD was classified based on the International photographic classification for pathologic myopia (META-PM).

Results

In the first analysis, comprising highly myopic cases with MMD (N = 348) versus emmetropic controls without MMD (N = 16,275), two SNPs were significantly associated with high myopia in adults with HM and MMD: (1) rs10824518 (P = 6.20E-07) in KCNMA1, which is highly expressed in human retinal and scleral tissues; and (2) rs524952 (P = 2.32E-16) near GJD2. In the second analysis, comprising highly myopic cases with MMD (N = 348) versus highly myopic controls without MMD (N = 898), none of the SNPs studied reached Bonferroni-corrected significance.

Conclusions

Of the 50 myopia-associated loci, we did not find any variant specifically associated with MMD, but the KCNMA1 and GJD2 loci were significantly associated with HM in highly myopic subjects with MMD, compared to emmetropes.

Prevention and Management of Myopia and Myopic Pathology

Myopia is fast becoming a global public health burden with its increasing prevalence, particularly in developed countries. Globally, the prevalence of myopia and high myopia (HM) is 28.3% and 4.0%, respectively, and these numbers are estimated to increase to 49.8% for myopia and 9.8% for HM by 2050 (myopia defined as -0.50 diopter [D] or less, and HM defined as -5.00 D or less). The burden of myopia is tremendous, as adults with HM are more likely to develop pathologic myopia (PM) changes that can lead to blindness. Accordingly, preventive measures are necessary for each step of myopia progression toward vision loss. Approaches to prevent myopia-related blindness should therefore attempt to prevent or delay the onset of myopia among children by increased outdoor time; retard progression from low/mild myopia to HM, through optical (e.g., defocus incorporated soft contact lens, orthokeratology, and progressive-additional lenses) and pharmacological (e.g., low dose of atropine) interventions; and/or retard progression from HM to PM through medical/surgical treatments (e.g., anti-VEGF therapies, macula buckling, and scleral crosslinking). Recent clinical trials aiming for retarding myopia progression have shown encouraging results. In this article, we highlight recent findings on preventive and early interventional measures to retard myopia, and current and novel treatments for PM.

The Effects of Different Outdoor Environments, Sunglasses and Hats on Light Levels: Implications for Myopia Prevention

Purpose

Lack of outdoor time is a known risk factor for myopia. Knowledge of the light levels reaching the eye and exposure settings, including sun-protective measures, is essential for outdoor programs and myopia. We evaluated the impact of sun-protective strategies (hat and sunglasses) on maintaining high illuminance levels to prevent myopia.

Methods

A child-sized mannequin head was developed to measure light illuminance levels with and without sun-protective equipment, across a wide range of environments in Singapore, outdoors (open park, under a tree, street) and indoors (under a fluorescent illumination with window, under white LED-based lighting without window). A comparison was made between indoor and outdoor light levels that are experienced while children are involved in day-to-day activities.

Results

Outdoor light levels were much higher (11,080-18,176 lux) than indoors (112-156 lux). The higher lux levels protective of myopia (>1000 lux) were measured at the tree shade (5556-7876 lux) and with hat (4112-8156 lux). Sunglasses showed lux levels between 1792 and 6800 lux. Although with sunglasses readings were lower than tree shade and hat, light levels were still 11 to 43 times higher than indoors.

Conclusions

Recommendations on spending time outdoors for myopia prevention with adequate sun protection should be provided while partaking in outdoor activities, including protection under shaded areas, wearing a hat or sunglasses, sunscreen, and adequate hydration.

Translational Relevance

Light levels outdoors were higher than indoors and above the threshold illuminance for myopia prevention even with adequate sun-protective measures.

Maternal and fetal genetic effects on birth weight and their relevance to cardio-metabolic risk factors

Birth weight variation is influenced by fetal and maternal genetic and non-genetic factors, and has been reproducibly associated with future cardio-metabolic health outcomes. In expanded genome-wide association analyses of own birth weight (n = 321,223) and offspring birth weight (n = 230,069 mothers), we identified 190 independent association signals (129 of which are novel). We used structural equation modeling to decompose the contributions of direct fetal and indirect maternal genetic effects, then applied Mendelian randomization to illuminate causal pathways. For example, both indirect maternal and direct fetal genetic effects drive the observational relationship between lower birth weight and higher later blood pressure: maternal blood pressure-raising alleles reduce offspring birth weight, but only direct fetal effects of these alleles, once inherited, increase later offspring blood pressure. Using maternal birth weight-lowering genotypes to proxy for an adverse intrauterine environment provided no evidence that it causally raises offspring blood pressure, indicating that the inverse birth weight-blood pressure association is attributable to genetic effects, and not to intrauterine programming.

Prevalence, Characteristics, and Risk Factors of Moderate or High Hyperopia among Multiethnic Children 6 to 72 Months of Age: A Pooled Analysis of Individual Participant Data

PURPOSE

To describe the prevalence, ocular characteristics, and associated risk factors of moderate to high hyperopia in early childhood.

DESIGN

Pooled analysis of individual participant data from population-based studies.

PARTICIPANTS

Six- to 72-month-old multiethnic children who participated in 4 population-based studies of pediatric eye diseases.

METHODS

The pooled studies conducted comparable parental interviews and ocular examinations including cycloplegic autorefraction. Presence of hyperopia was defined based on cycloplegic refractive error in the worse eye. Multivariate analyses were performed to evaluate the association of potential risk factors with hyperopia risk.

MAIN OUTCOME MEASURES

Prevalence and odds ratios of moderate to high hyperopia (≥4.0 diopters [D]).

RESULTS

Cycloplegic refraction was completed in 15 051 children 6 to 72 months of age. Among these children, the overall prevalence of moderate to high hyperopia (≥4.0 D) in the worse eye was 3.2% (95% confidence interval, 2.9%-3.5%), accounting for 15.6% of all hyperopia (≥2.0 D). Among children with moderate to high hyperopia, both eyes were affected in 64.4%, 28.9% showed spherical anisometropia of 1.0 D or more, and 19.5% showed astigmatism of 1.5 D or more. Among 36- to 72-month-old children with moderate to high hyperopia, 17.6% wore glasses. Prevalence of moderate to high hyperopia was slightly less in 12- to 23-month-old children and was relatively stable in children 24 months of age and older. Non-Hispanic and Hispanic white race and ethnicity, family history of strabismus, maternal smoking during pregnancy, and being a participant in the United States studies were associated with a higher risk of moderate to high hyperopia (P < 0.05).

CONCLUSIONS

By assembling similarly designed studies, our consortium provided robust estimates of the prevalence of moderate to high hyperopia in the general population and showed that in 6- to 72-month-old children, moderate to high hyperopia is not uncommon and its prevalence does not decrease with age. Risk factors for moderate to high hyperopia differ from those for low to moderate hyperopia (2.0-<4.0 D) in preschool children, with family history of strabismus and maternal smoking during pregnancy more strongly associated with moderate to high hyperopia than low to moderate hyperopia.