Regional/ethnic differences in ocular axial elongation and refractive error progression in myopic and non-myopic children.

AIM: To determine the regional and ethnic differences in ocular axial elongation and refractive error progression in myopic and non-myopic children. METHODS: A retrospective analysis of 15 longitudinal clinical and population-based studies was conducted in the UK, Sweden, Australia (classified as European), China, and Vietnam (classified as East Asian) between 2005 and 2021. A total of 14,593 data points from 6208 participants aged 6-16 years with spherical equivalent from +6 to -6 D were analysed. Progression was annualised from longitudinal axial length and cycloplegic spherical equivalent (SE) refraction. Generalised estimating equation models including main effects and interactions were used for model building. Age and region-specific estimates for myopes and non-myopes and confidence intervals are reported. RESULTS: Factors affecting axial elongation and SE progression in children included being myopic, followed by age, region/ethnicity and sex. The magnitude of regional/ethnic differences was dependent on myopia and age. Axial elongation and SE progression were lower in European compared with East Asian children, but differences were reduced with increasing age and differences in axial elongation were larger in myopes than non-myopes. Age-specific regional/ethnic differences indicated that axial elongation for a 6-year-old East Asian myopic child was greater than a European child by 0.15 mm/year (0.58 vs. 0.43 mm/year) and by 0.09 mm/year (0.35 vs. 0.26 mm/year) for a 10-year-old myope. SE progression was lower in a 6-year-old European myope by 0.48 D/year and at 10 years of age by 0.34 D/year compared with an East Asian myope. CONCLUSIONS: There are regional/ethnic differences in age-specific refractive and axial growth patterns in both myopic and non-myopic eyes, with more marked differences in younger East Asian children who demonstrated a higher axial growth and greater negative SE shift than their non-Asian peers. Regional/ethnic differences in progression reflect environmental and ethnic variations. Age and region/ethnicity-specific estimates could contribute as a reference for future comparisons.

Late Bedtime and Altered Diurnal Axial Length Rhythms of the Eye.

PURPOSE: Affecting one-third of the population worldwide and increasing, the sight-threatening condition myopia is causing a significant socio-economic burden. To better understand its etiology, recent studies investigated the role of ocular and systemic rhythms, yet results are conflicting. Here we profiled 24-h variations of axial length of the eye and salivary melatonin concentration in young adults with and without myopia and explored the potential impacts of bedtime on these rhythms. METHODS: A total of 25 healthy young adults (age 25.0 ± 4.8 years, 13 females) completed this study, including 13 myopes (mean spherical equivalent refractive error -2.93 ± 1.46 diopters) and 12 non-myopes (0.14 ± 0.42 diopters). Saliva sample collection and axial length measurements were repeated for seven times over 24 h starting from 8 am. Information on sleep and chronotype was collected at first visit with the Pittsburgh Sleep Quality Index and the Morningness-Eveningness Questionnaire. RESULTS: Significant diurnal rhythms of axial length and salivary melatonin concentration were identified in both refractive groups (both p < 0.001), with no myopia-related rhythm difference (interaction of measurement time-point × myopia, p = 0.9). Late bedtime was associated with altered rhythms (p = 0.009) and smaller diurnal change (p = 0.01) in axial length. Elevated melatonin levels were observed in myopes (p = 0.006) and in late sleepers (p = 0.017). CONCLUSIONS: These findings suggest that sleep/wake cycles may be involved in the regulation of axial length rhythms. Further research is needed to determine if there exists a causal relationship between the two.

Comparison between cycloplegic and noncycloplegic refraction in young adult myopes.

SIGNIFICANCE: This study explores the difference between cycloplegic and noncycloplegic refraction in young adult myopes. PURPOSE: From the available literature, it is unclear whether cycloplegia is necessary when refracting young adults. This study investigates the agreement between noncycloplegic autorefraction and cycloplegic autorefraction and investigates factors affecting the agreement between the two methods. METHODS: In total, 125 myopes with ages ranging between 18 and 26 years were included from Australia and Vietnam. Each participant underwent noncycloplegic autorefraction and cycloplegic autorefraction. Cycloplegia was induced with 1% ophthalmic tropicamide. RESULTS: The mean spherical equivalent difference (95% confidence interval) between noncycloplegic autorefraction and cycloplegic autorefraction was -0.20 D (-0.25 to -0.14 D; t124 = -7.18, p<0.0001 ) . A mean difference of >0.25 D was seen in 46.8% of eyes. The lower and upper limits of agreement were -0.80 and 0.41 D, respectively. With univariate analysis, factors including age, degree of refractive error, accommodation amplitude, and distance phorias showed no impact on the average difference between cycloplegic autorefraction and noncycloplegic autorefraction. Yet, eyes with near exophoria ( F2,120 = 6.63, p=0.0019) and Caucasian eyes ( F3,121 = 2.85, p=0.040) exhibited the smallest paired differences. However, in the multivariate analysis, only near exophoria was associated with a lower mean difference. A significantly smaller proportion (34.9%) of eyes with near exophoria had a paired difference of -0.25 D or more compared with esophoria (50%) and orthophoria (65%; χ2 = 6.6, p=0.038). CONCLUSIONS: Noncycloplegic autorefraction results in more myopic refractive error than cycloplegic autorefraction in young adults.

Incidence of myopia in Swedish schoolchildren: A longitudinal study.

PURPOSE: The prevalence of myopia in Scandinavia tends to be lower than in other parts of the world. This study aimed to investigate the incidence of myopia and its predictors in Swedish children to characterise this trend. METHODS: A 2-year longitudinal study was conducted following a cohort of schoolchildren aged 8-16 years. Myopia was defined as a spherical equivalent refraction (SER) ≤ -0.50 D. The study enrolled 128 participants, 70 (55%) females with a mean age of 12.0 years (SD = 2.4). RESULTS: The cumulative incidence of myopia during the follow-up period was 5.5%, and the incidence rate of myopia was 3.2 cases per 100 person-years. Participants with myopia at baseline exhibited a faster increase in refractive error during the follow-up period. Likewise, participants with two myopic parents exhibited a more marked change towards myopia, regardless of their initial refractive error. CONCLUSION: In the current study, similar to prevalence, the incidence of myopia was low when compared with other parts of the world. These results lead us to formulate a new hypothesis that the normal emmetropisation process may be protected by low educational pressure practised in Sweden during early childhood. Further research is necessary to test this new hypothesis.

Epithelial Immune Cell Response to Initial Soft Contact Lens Wear in the Human Corneal and Conjunctival Epithelium.

Purpose: The purpose of this study was to assess the immediate ocular immune response to soft contact lens (CL) wear by examining presumed epithelial immune cell (EIC) density and morphology at the central, peripheral, limbal cornea, and conjunctiva. Methods: Fifty-four participants naïve to CL wear (mean age = 24.8 ± 9.8 years, 44% female participants), were examined using in vivo confocal microscopy at baseline and after 2 hours of CL wear (1-Day ACUVUE MOIST). Images were captured at the central, temporal far peripheral and limbal cornea, and bulbar conjunctiva. EIC density was counted manually and morphology was graded. Differences in EIC parameters pre- and post-CL wear were examined using a generalized estimating equation model with appropriate post hoc analyses. Results: After 2 hours of soft CL wear, there was a significant increase in EIC density in all regions other than the central cornea (all P < 0.001). Cell body size was significantly larger, and a higher proportion of participants exhibited EIC with long dendrites after lens wear at the central and peripheral cornea (both P < 0.001). There was a significant increase in the number of participants displaying EIC with thick dendrites at the peripheral (P = 0.04) and limbal cornea (P < 0.001) after lens wear. Conclusions: EICs were primarily recruited to the peripheral regions, whereas the central cornea shows no significant recruitment after short-term CL wear. Both central and peripheral corneas exhibited an enhanced antigen capture capacity, whereas migratory capacity was increased in the peripheral corneal regions suggesting EIC activation following a short period of CL wear.

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.

Myopia Progression in Adults: A Retrospective Analysis.

SIGNIFICANCE: Studies on adult myopia progression are limited. This retrospective analysis of a large data set of young adult myopes characterizes myopia progression during adulthood. PURPOSE: This study aimed to determine the mean annual progression of myopia and to estimate the proportion of progressors in adult myopes. METHODS: Longitudinal, noncycloplegic subjective refraction data for young adult myopes (spherical equivalent refractive error, -0.5 D or more), age ranging from 18 to 30 years, were retrospectively analyzed. The mean annual progression, as well as the proportion of progressors (at least -0.50 D shift between visits and annualized progression of -0.25 D or more), was estimated. RESULTS: A total of 354 myopes (230 females [64.7%]), with a mean (standard deviation) age of 22.2 (3.8) years, were considered. The mean (standard deviation) annualized progression was -0.10 (0.21), -0.08 (0.2), and -0.04 (0.21) D in the 18- to 21-year, 22- to 26-year, and 27- to 30-year age groups, respectively ( P = .003). The difference between 18- to 21- and 27- to 30-year age groups was significant ( P = .05), whereas all other pairwise comparisons were not significant. The proportion (95% confidence interval) of progressors in the 18- to 21-, >21- to 26-, and >26- to 30-year age groups was 18.3% (14.9 to 21.7%), 10.9% (7.1 to 14.7%), and 8.8% (4.4 to 13.1%), respectively. The proportion of progressors working or studying in a higher learning/academic environment was 16.2% with an odds ratio (95% confidence interval) for progression of 2.07 (1.15 to 3.74) compared with those in nonacademic environments ( P = .02), with no significant effect of sex or ethnicity. CONCLUSIONS: This study is consistent with other studies on myopia in young adults, which show that myopia does not progress by substantial amounts throughout the adult years, particularly after the age of 21 years. Although future studies may be challenged by the small rates of change and the small proportion of progressors, further research is needed to understand the implications of adult myopia progression on clinical management.

Myopia and sleep in children-a systematic review.

Worldwide, approximately one in three people are myopic or short-sighted. Myopia in children is of particular concern as younger onset age implies a higher risk of progression, and consequently greater risk of developing vision-threatening complications. The importance of sleep in children's health has long been acknowledged, but evidence for its role in childhood myopia is fairly new and mixed results were presented across studies. To facilitate better understanding of this relationship, a broad literature search, up to and including October 31, 2022, was performed using three databases (PubMed, Embase, and Scopus). Seventeen studies were included in the review, covering four main aspects of sleep, namely duration, quality, timing, and efficiency, and their associations with myopia in children. The present literature review discussed these studies, revealed potential limitations in their methodologies, and identified gaps that need to be addressed in the future. The review also acknowledges that current evidence is insufficient, and the role of sleep in childhood myopia is far from being fully understood. Future studies that primarily, objectively, and accurately assess sleep and myopia, taking other characteristics of sleep beyond duration into consideration, with a more diverse sample in terms of age, ethnicity, and cultural/environmental background, and control for confounders such as light exposure and education load are much needed. Although more research is required, myopia management should be a holistic approach and the inclusion of sleep hygiene in myopia education targeting children and parents ought to be encouraged.

Normative data for axial elongation in Asian children.

AIM: To determine the influence of refractive error (RE), age, gender and parental myopia on axial elongation in Chinese children and to develop normative data for this population. METHODS: This is a retrospective analysis of eight longitudinal studies conducted in China between 2007 and 2017. Data of 4701 participants aged 6-16 years with spherical equivalent from +6 to -6D contributed to one, two or three annualised progression data resulting in a dataset of 11,262 eyes of 26.6%, 14.8% and 58.6% myopes, emmetropes and hyperopes, respectively. Longitudinal data included axial length and cycloplegic spherical equivalent RE. Axial elongation was log-transformed to develop an exponential model with generalised estimating equations including main effects and interactions. Model-based estimates and their confidence intervals (CIs) are reported. RESULTS: Annual axial elongation decreased significantly with increasing age, with the rate of decrease specific to the RE group. Axial elongation in myopes was higher than in emmetropes and hyperopes but these differences reduced with age (0.58, 0.45 and 0.27 mm/year at 6 years and 0.13, 0.06 and 0.05 mm/year at 15 years for myopes, emmetropes and hyperopes, respectively). The rate of elongation in incident myopes was similar to that in myopes at baseline (0.33 vs. 0.34 mm/year at 10.5 years; p = 0.32), while it was significantly lower in non-myopes (0.20 mm/year at 10.5 years, p < 0.001). Axial elongation was greater in females than in males and in those with both parents myopic compared with one or no myopic parent, with larger differences in non-myopes than in myopes (p < 0.01). CONCLUSIONS: Axial elongation varied with age, RE, gender and parental myopia. Estimated normative data with CIs could serve as a virtual control group.

Time outdoors positively associates with academic performance: a school-based study with objective monitoring of outdoor time.

BACKGROUND: To explore the relationship between outdoor time and academic performance among school-aged children. METHODS: This study was designed as a cross-sectional study. Data were derived from a school-based prospective children myopia intervention study (STORM). Outdoor time was recorded by self-developed algorithm-validated wristwatches in real-time and calculated as the cumulative average of 10 months. The academic performance was recorded and provided by the participating schools and further standardized. Other information was collected using an online standardized questionnaire. Mixed-effects model and B-Spline method were used to investigate the association between time spent on different types of daily activity, including outdoor activity and academic performance. RESULTS: A total of 3291 children with mean age 9.25 years were included in the final analysis. Overall, outdoor time was associated with academic performance in a non-linear manner; specifically, not exceeding 2.3 h per day, outdoor time was positively associated with academic performance; exceeding 2.3 h per day, this association became non-significant. Likewise, daily sleep duration and out-of-school learning time were associated with academic performance in a non-linear manner, resulting in turning points of 11.3 and 1.4 h per day, respectively. Separate analysis showed that outdoor time and sleep duration but not out-of-school learning time were positively associated with academic performance in Chinese, mathematics and English. CONCLUSION: Outdoor time, sleep duration and out-of-school learning time were associated with academic performance in a non-linear manner. Promotion of outdoor time may not negatively impact on academic performance. TRIAL REGISTRATION: Our study was registered in ClinicalTrials.gov (Identifier: NCT02980445).

Comparing children's, teenagers' and young adults' subjective responses to myopia control contact lenses.

INTRODUCTION: Myopia control (MC) studies in children link efficacy with subjective performance. There is little MC research in teenagers and young adults. This study compared subjective experience of MC contact lenses in different age groups. METHODS: Data were retrospectively reviewed from two double-masked, bilateral wear, crossover contact lens clinical trials (myopia -0.75D to -3.50D and <1.00 DC; 9-35 years). Participants wore two novel lenses (MC lenses with relative peripheral plus [+1.50D and +2.50D]) and a single-vision (SV) control lens (Clariti® 1 day) for 1 week each. All lenses were made from Somofilcon A material. Data collected included visual acuity (VA), wearing time, subjective ratings of comfort, distance and near vision clarity and overall vision. Generalised estimating equations with subject random intercepts and identity link functions were used in the analysis. RESULTS: A total of 31 participants (10 children, 11 teenagers and 10 adults) were included, with no difference between the age groups for VA with the dispensed lenses (p > 0.05). All groups could discriminate between the SV and MC lenses for vision (distance, near and overall) after 1 week (p < 0.05). There was no difference between groups for comfort or distance and near vision. Children rated the overall vision quality higher than teenagers and adults for both SV and MC lenses (p < 0.05), but there was no difference relative to the SV lens between groups (p > 0.50). Daily wear time was lowest for children for all lens types (all p < 0.02). Wear time was positively associated with ratings of overall vision quality for children and young adults (both p < 0.05). CONCLUSION: All age groups rated SV lenses higher than MC lenses. Subjective ratings of MC lenses appear similar between age groups relative to SV lenses. Wear time was lowest in children and was correlated with overall vision quality ratings in children and young adults.

Axial length changes in progressive and non-progressive myopic children in China.

PURPOSE: Due to pubertal development and crystalline lens compensation, axial length (AL) continues to increase among non-progressive myopic children (absolute annual spherical equivalent (SE) progression less than 0.25 diopter), but the amount is unknown. This study was to investigate the cutoff of AL change to accurately differentiate between progressive and non-progressive myopes. METHODS: A total of 8,546 myopic and treatment-naive children aged 6-10 years were enrolled from two cohort studies. AL with optical biometer and cycloplegic SE with auto refraction were evaluated at baseline and annually. Annual AL change was calculated, and the percentiles of annual axial elongation among progressive and non-progressive myopes were estimated by quantile regression with restricted cubic spline. Area under receiver-operating characteristic (ROC) curve (AUROC), positive predictive value (PPV), and negative predictive value (NPV) were applied to evaluate the accuracy of predicting progressive and non-progressive myopes. RESULTS: Among 8,546 myopic children, 603 (7.06%) were non-progressive myopes. Annual AL changes among non-progressive myopes remained stable with the median annual change being 0.25 mm, while the median for progressive myopes decreased with age from 0.58 to 0.42 mm. AUROC for distinguishing between non-progressive and progressive myopes was 0.88 and was > 0.85 for each age group. Annual AL change, the cutoff of 0.20 mm/year, had significantly high PPV and NPV in predicting progressive myopes with high proportion of progressive myopes and non-progressive myopes with low proportions of progressive myopes. CONCLUSION: Myopic children with non-progressive status had markedly less axial elongation than progressive ones. AL changes with cutoff of 0.20 mm/year could differentiate between non-progressive and progressive status and may be an alternative for evaluating progressive status.

Normative data and percentile curves for axial length and axial length/corneal curvature in Chinese children and adolescents aged 4-18 years.

PURPOSE: To develop age-specific and gender-specific reference percentile charts for axial length (AL) and AL/corneal radius of curvature (AL/CR) and, to use percentiles to determine probability of myopia and estimate refractive error (RE). METHODS: Analysis of AL, cycloplegic RE and CR of 14 127 Chinese participants aged 4-18 years from 3 studies. AL and AL/CR percentiles estimated using Lambda-Mu-Sigma method and compared for agreement using intraclass correlation (ICC). Logistic regression was used to model risk of myopia based on age, gender, AL and AL/CR percentiles. Accuracy of AL progression and RE estimated using percentiles was validated using an independent sample of 5742 eyes of children aged 7-10 years. RESULTS: Age-specific and gender-specific AL and AL/CR (3rd, 5th, 10th, 25th, 50th, 75th, 90th and 95th) percentiles are presented. Concordance between AL and AL/CR percentiles improved with age (0.13 at 4 years to >0.75 from 13 years) and a year-to-year change was observed for all except <10th percentile from 15 years. Increasing age, AL and AL/CR was associated with a more myopic RE (r2=0.45,0.70 and 0.83, respectively). The sensitivity and specificity of the model to estimate probability of myopia was 86.0% and 84.5%, respectively. Estimation of 1-year change in AL using percentiles correlated highly with actual AL (ICC=0.98). Concordance of estimated to actual RE was high (ICC=0.80) and within ±0.50D and ±1.0D of actual RE for 47.4% and 78.9% of eyes, respectively. CONCLUSION: Age-specific and gender-specific AL and AL/CR percentiles provide reference data, aid in identifying and monitoring individuals at risk of myopia and have utility in screening for myopia. AL/CR percentiles were more accurate in estimating probability of myopia in younger children.

Spectacle Lenses With Highly Aspherical Lenslets for Slowing Myopia: A Randomized, Double-Blind, Cross-Over Clinical Trial: Parts of these data were presented as a poster at the Annual Research in Vision and Ophthalmology meeting, 2022.

PURPOSE: To evaluate myopia progression with highly aspherical lenslet (HAL) spectacles vs conventional single vision (SV) spectacles. DESIGN: Prospective, double-blind, single-center, randomized, cross-over trial. METHOD: A total of 119 Vietnamese children (7-13 years of age, spherical equivalent refractive error [SE] = -0.75 to -4.75D) were randomized to wear either HAL or SV, and after 6 months (stage 1) crossed over to the other lens for another 6 months (stage 2). At the end of stage 2, both groups wore HAL for a further 6 months. In the order that lenses were worn at each stage, group 1 was designated HSH (HAL-SV-HAL) and group 2 SHH (SV-HAL-HAL). The main outcome measures were a comparison between HAL and SV for change (Δ) in SE and axial length (AL) during each stage; and a comparison of ΔSE/AL with SV between HSH and SHH groups to determine whether myopia rebounded when switched from HAL to SV (HSH group). RESULTS: Myopia progressed more slowly with HAL than with SV during stages 1 and 2 (SEΔ stage 1: -0.21 vs -0.27D, P = .317, stage 2: -0.05 vs -0.32D, P < .001; ALΔ stage 1: 0.07 vs 0.14 mm, P = .004; stage 2: 0.04 vs 0.17 mm, P < .001). ΔSE/AL with SV was not different between the HSH and SHH groups (ΔSE -0.33 ± 0.27D vs -0.27 ± 0.42D, P = .208; ΔAL 0.17 ± 0.13mm vs 0.13 ± 0.15 mm, P = .092). An average of 14 hours per day of lens wear was reported with both lenses. CONCLUSIONS: In this cross-over trial, intergroup and intragroup comparisons indicate that HAL slows myopia. Children were compliant with lens wear, and data were not suggestive of rebound when patients were switched from HAL to SV.

Establishing a method to estimate the effect of antimyopia management options on lifetime cost of myopia.

BACKGROUND: Informed decisions on myopia management require an understanding of financial impact. We describe methodology for estimating lifetime myopia costs, with comparison across management options, using exemplars in Australia and China. METHODS: We demonstrate a process for modelling lifetime costs of traditional myopia management (TMM=full, single-vision correction) and active myopia management (AMM) options with clinically meaningful treatment efficacy. Evidence-based, location-specific and ethnicity-specific progression data determined the likelihood of all possible refractive outcomes. Myopia care costs were collected from published sources and key informants. Refractive and ocular health decisions were based on standard clinical protocols that responded to the speed of progression, level of myopia, and associated risks of pathology and vision impairment. We used the progressions, costs, protocols and risks to estimate and compare lifetime cost of myopia under each scenario and tested the effect of 0%, 3% and 5% annual discounting, where discounting adjusts future costs to 2020 value. RESULTS: Low-dose atropine, antimyopia spectacles, antimyopia multifocal soft contact lenses and orthokeratology met our AMM inclusion criteria. Lifetime cost for TMM with 3% discounting was US$7437 (CI US$4953 to US$10 740) in Australia and US$8006 (CI US$3026 to US$13 707) in China. The lowest lifetime cost options with 3% discounting were antimyopia spectacles (US$7280, CI US$5246 to US$9888) in Australia and low-dose atropine (US$4453, CI US$2136 to US$9115) in China. CONCLUSIONS: Financial investment in AMM during childhood may be balanced or exceeded across a lifetime by reduced refractive progression, simpler lenses, and reduced risk of pathology and vision loss. Our methodology can be applied to estimate cost in comparable scenarios.

Prevalence and Patterns of Refractive Errors in Children and Young Adults in an Urban Region in South India: the Hyderabad Eye Study.

PURPOSE: To determine the prevalence of refractive error (RE) and associated risk factors for myopic refractive errors in children and young adults from the urban region of Hyderabad, South India. METHODS: Four thousand sixty-five (4,065) participants aged 6-22 years were enrolled and examined in this cross-sectional study conducted from October 2013 to January 2015. Participants were enrolled from a random sample of schools and universities in regions representative of urban Hyderabad. RE was determined using cycloplegic autorefraction. The association of demographic factors such as age, gender, and socio-economic category (SEC) (low/mid/high) with myopia was explored with logistic regression with robust standard error. RESULTS: Of the total participants, 2,259 were children aged 6-15 years and 1,806 were adolescents and young adults aged 16-22 years. Overall prevalence of myopia, high myopia (≤ -5.00D and ≤ -6.00 D), hyperopia, emmetropia, and astigmatism was 29.8% (95% CI: 26.0% to 33.6%, n = 1,216), 2.9% (95% CI: 1.9% to 3.9%, n = 120), 1.1% (95%CI: 0.7% to 1.5%, n = 46), 14.7% (95% CI: 12.4% to 17.0%, n = 599), 46.9% (95% CI: 43.7% to 50.1%, n = 1913) and 8.6% (95% CI: 7.4% to 9.9%, n = 352) respectively. A strong correlation existed between age and prevalence of myopia (R2 = 0.88, p < .001) and high myopia (R2 = 0.71, p < .001). Children from schools of low SEC (34.7%) had higher prevalence of myopia compared to the mid SEC (16.8%) (p = .043). CONCLUSION: Myopia was the most prevalent refractive error and increased with age in this urban population. More myopia was observed in schools of low SEC.

Efficacy of contact lenses for myopia control: Insights from a randomised, contralateral study design.

PURPOSE: To determine the efficacy of two myopia control contact lenses (CL) compared with a single-vision (SV) CL. METHODS: Ninety-five Chinese children with myopia, aged 7-13 years in a 1-year prospective, randomised, contralateral, cross-over clinical trial with 3 groups; bilateral SVCL (Group I); randomised, contralateral wear of an extended depth of focus (EDOF) CL and SVCL (Group II) and MiSight® CL and SVCL (Group III). In Groups II and III, CL were crossed over at the 6-month point (Stage 1) and worn for a further 6 months (Stage 2). Group I wore SVCL during both stages. At baseline and the end of each stage, cycloplegic spherical equivalent refractive error (SE) and axial length (AL) were measured. Six-monthly ΔSE/ΔAL across groups was analysed using a linear mixed model (CL type, stage, eye and eye* stage included as factors). Intra-group paired differences between eyes were determined. RESULTS: In Group I, mean (SD) ΔSE/ΔAL with SVCL was -0.41 (0.28) D/0.13 (0.09) mm and -0.25 (0.27) D/0.16 (0.09) mm for stages 1 and 2, with a mean paired difference between eyes of 0.01 D/0.01 mm and 0.05 D/-0.01 mm, respectively. ΔSE/ΔAL with SVCL was similar across Groups I to III (Stage 1: p = 0.89/0.44, Stage 2: p = 0.70/ 0.64). In Groups II and III, ΔSE/ΔAL was lower with the EDOF and MiSight® CL than the contralateral SVCL in 68% to 94% of participants, and adjusted 6-month ΔSE/ΔAL with EDOF was similar to MiSight® (p = 0.49/0.56 for ΔSE/ΔAL, respectively). Discontinuations across the three groups were high, but not different between the groups (33.3%, 48.4% and 50% for Groups I to III, respectively [p = 0.19]) and most discontinuations occurred immediately after baseline. CONCLUSIONS: Extended depth of focus and MiSight® CL demonstrated similar efficacy in slowing myopia. When switched from a myopia control CL to SVCL, myopia progression was similar to that observed with age-matched wearers in SVCL and not suggestive of rebound.

Time Outdoors in Reducing Myopia: A School-Based Cluster Randomized Trial with Objective Monitoring of Outdoor Time and Light Intensity.

PURPOSE: To evaluate the efficacy of time outdoors per school day over 2 years on myopia onset and shift. DESIGN: A prospective, cluster-randomized, examiner-masked, 3-arm trial. PARTICIPANTS: A total of 6295 students aged 6 to 9 years from 24 primary schools in Shanghai, China, stratified and randomized by school in a 1:1:1 ratio to control (n = 2037), test I (n = 2329), or test II (n = 1929) group. METHODS: An additional 40 or 80 minutes of outdoor time was allocated to each school day for test I and II groups. Children in the control group continued their habitual outdoor time. Objective monitoring of outdoor and indoor time and light intensity each day was measured with a wrist-worn wearable during the second-year follow-up. MAIN OUTCOME MEASURES: The 2-year cumulative incidence of myopia (defined as cycloplegic spherical equivalent [SE] of ≤-0.5 diopters [D] in the right eye) among the students without myopia at baseline and changes in SE and axial length (AL) after 2 years. RESULTS: The unadjusted 2-year cumulative incidence of myopia was 24.9%, 20.6%, and 23.8% for control, test I, and II groups, respectively. The adjusted incidence decreased by 16% (incidence risk ratio [IRR], 0.84; 95% confidence interval [CI], 0.72-0.99; P = 0.035) in test I and 11% (IRR = 0.89; 95% CI, 0.79-0.99; P = 0.041) in test II when compared with the control group. The test groups showed less myopic shift and axial elongation compared with the control group (test I: -0.84 D and 0.55 mm, test II: -0.91 D and 0.57 mm, control: -1.04 D and 0.65 mm). There was no significant difference in the adjusted incidence of myopia and myopic shift between the 2 test groups. The test groups had similar outdoor time and light intensity (test I: 127 ± 30 minutes/day and 3557 ± 970 lux/minute; test II: 127 ± 26 minutes/day and 3662 ± 803 lux/minute) but significantly more outdoor time and higher light intensity compared with the control group (106 ± 27 minutes/day and 2984 ± 806 lux/minute). Daily outdoor time of 120 to 150 minutes at 5000 lux/minutes or cumulative outdoor light intensity of 600 000 to 750 000 lux significantly reduced the IRR by 15%～ 24%. CONCLUSIONS: Increasing outdoor time reduced the risk of myopia onset and myopic shifts, especially in nonmyopic children. The protective effect of outdoor time was related to the duration of exposure and light intensity. The dose-response effect between test I and test II was not observed probably because of insufficient outdoor time achieved in the test groups, which suggests that proper monitoring on the compliance on outdoor intervention is critical if one wants to see the protective effect.

Automated analysis of corneal nerve tortuosity in diabetes: implications for neuropathy detection.

CLINICAL RELEVANCE: There is potential benefit in analysing corneal nerve tortuosity as a marker for assessment and progression of systemic diabetic neuropathy. BACKGROUND: The aim of this work was to determine whether tortuosity significantly differs in participants with type 1 (T1DM) and type 2 (T2DM) diabetes compared to controls and whether tortuosity differed according to neuropathy status. METHODS: Corneal nerves of 164 participants were assessed across T1DM, T2DM and control groups. Images of corneal nerves were captured via in vivo corneal confocal microscopy. Diabetic neuropathy status was examined using the Total Neuropathy Score (TNS). Tortuosity was assessed with Cfibre v0.097. Results were compared between groups with a linear mixed model accounting for location of image and controlling for age, producing Tortuosity Factor (TF), an estimate of the marginal means of each group. RESULTS: Tortuosity was significantly reduced in the T1DM group compared to controls (TF = 0.241, 95%CI = 0.225-0.257 vs. TF = 0.272, 95%CI = 0.252-0.292; mean difference = -0.031, p = 0.02) and in the T2DM group compared to controls (TF = 0.261, 95%CI = 0.244-0.278 vs. TF = 0.289, 95%CI = 0.270-0.308; mean difference = -0.029, p = 0.03). Tortuosity did not significantly differ between participants with T1DM and T2DM accounting for age and TNS (TF = 0.240, 95%CI = 0.215-0.265 vs. 0.269, 95%CI = 0.244-0.293, mean difference = -0.029, p = 0.11). Tortuosity was significantly reduced in participants with neuropathy (TNS≥2) compared to participants with no neuropathy (TNS< 2) (TF = 0.248, 95%CI = 0.231-0.265 vs. TF = 0.272, 95%CI = 0.260-0.283; mean difference = -0.024, p = 0.03). CONCLUSIONS: Tortuosity is significantly reduced in participants with T1DM and T2DM compared to age matched controls and in participants with neuropathy compared to those without neuropathy.