Direct costs of myopia in Singapore

The effect of individualized ocular refraction customized spectacle lenses on myopia control in schoolchildren: A 1-year randomised clinical trial

PURPOSE

The aim of this study was to investigate the effect of individualized ocular refraction customized (IORC) spectacle lenses with different actual amounts of peripheral myopic defocus (MD) on myopia control over 1 year. These lenses compensate for the original peripheral refraction via the free-form surface on the back of the lens.

METHODS

This 1-year, double-masked randomised clinical trial included 184 myopic schoolchildren aged 8-12 years. Participants were randomised to receive IORC lenses with high (IORC-H group, +4.50 D), medium (IORC-M group, +3.50 D) or low (IORC-L group, +2.50 D) MD or single-vision (SV) lenses. The spherical equivalent refractive error (SER) and axial length (AL) were measured at baseline and 6-monthly intervals.

RESULTS

After 1 year, the mean (SD) changes in SER were -0.18 (0.37), -0.36 (0.37), -0.52 (0.39) and -0.60 (0.42) D for the IORC-H, IORC-M, IORC-L and SV groups, respectively. Compared with the SV group, the effects of slowing myopia progression were 70%, 40% and 13% for the IORC-H (difference of 0.47 D, p < 0.001), IORC-M (difference of 0.32 D, p = 0.001) and IORC-L (difference of 0.15 D, p > 0.05) groups, respectively. The mean (SD) changes in AL were 0.12 (0.16), 0.23 (0.17), 0.29 (0.17) and 0.36 (0.17) mm for the IORC-H, IORC-M, IORC-L and SV groups, respectively. The axial elongation was 67%, 36% and 19% lower in the IORC-H (difference of 0.25 mm, p < 0.001), IORC-M (difference of 0.15 mm, p < 0.001) and IORC-L (difference of 0.10 mm, p = 0.04) groups, respectively, compared with the SV group. The IORC-H group exhibited significantly less axial elongation than the IORC-M and IORC-L groups (p = 0.01 and p < 0.001, respectively).

CONCLUSION

Compared with the IORC-M and IORC-L lenses, the IORC-H lens was found to have superior efficacy in inhibiting myopic progression and slowing eye growth in schoolchildren, with better myopia control efficacy in younger children.

A new look at the myopia control efficacy of orthokeratology

PURPOSE

To evaluate the efficacy of orthokeratology contact lens wear in slowing the axial elongation of the eye in myopic children.

METHODS

Data from three prospective studies, which evaluated the use of orthokeratology for slowing myopia progression in children in comparison to a parallel control group of distance, single-vision spectacle lens wearers over a 2-year period, were pooled together for analysis.

RESULTS

Collectively, data from 125 orthokeratology and 118 control subjects were analyzed in this study. Of these, 101 (81 %) and 88 (75 %) orthokeratology and control subjects completed the 2-year follow-up period, respectively. Statistically significant differences in the change in axial length from baseline were found over time, between groups and for the time*group interaction (all p < 0.001), indicating that the rate of increase in axial length over time was significantly lower in the orthokeratology versus the control group. The lower axial elongation of the orthokeratology versus the control group was statistically significant at all time points (all p < 0.001), with significant differences being also present between each of the different pairs of time points (all p < 0.001). The interactions of group with age, gender, mean spherical refractive error and ethnicity at baseline were not significant (p > 0.05). The change in axial length at the 2-year visit in comparison to baseline for the orthokeratology and control groups were 0.41 ± 0.25 and 0.65 ± 0.30 mm, respectively, thus providing a treatment effect following 2-years of lens wear of 0.24 mm (95 % confidence intervals: 0.15 to 0.34 mm). About 40 % and 25 % of the orthokeratology subjects experienced remarkably low and high levels of myopia progression, respectively (2-years axial elongation: ≤0.30 mm and >0.59 mm, respectively).

CONCLUSIONS

Orthokeratology lens wear slows the axial elongation of the eye in comparison to spectacle lens wear in myopic children. The use of these lenses for slowing myopia progression appears to be very effective and not effective at all in 40% and 25% of orthokeratology lens wearers, respectively.

How can we better evaluate paediatric progression of myopia and associated risk factors? Lessons from the COVID-19 pandemic: A systematic review

PURPOSE

During the COVID-19 pandemic, home-based and remote learning-particularly using electronic devices-was rapidly pushed out. Increased near-work, screen time exposure and lack of outdoor time are risk factors that contribute to childhood myopia, but it is difficult to adopt recommendations from prior publications as a consistent limitation in the literature is the heterogeneity of research methodology. This review seeks to systematically evaluate how observational studies published during the pandemic have quantified and measured risk factors and myopia in school-going children and adolescents.

METHODS

Three scientific databases (PubMed, CINAHL, Scopus) were systematically searched from March 2020 to April 2022. Findings from relevant studies were descriptively summarised in relation to the PICOS-based objective of the review.

RESULTS

The final sample of 13 studies included research from six countries and comprised 1 411 908 children and adolescents. The majority of studies (N = 10; 76.9%) used spherical equivalent refraction (SER) of -0.5 dioptres or lower as a common definition of myopia. Most studies (77.8%) measuring screen time exposure found it higher during COVID-19 compared to pre-COVID, but only one study used objective measurement of screen time. The average critical appraisal score of the sample was only 66.1%, with a considerable number of studies failing to identify and adjust for potential confounders.

CONCLUSION

Future studies should consider emergent objective and validated measures of risk factors, account for potential a priori confounders and covariates and ensure more representativeness in the sociodemographic makeup of their samples.

Prevalence of and risk factors for myopia among urban and rural children in Northeast China: protocol for a school-based cross-sectional study

INTRODUCTION

The worldwide prevalence of myopia is high and continues to increase. In this study, a school screening programme for myopia will be implemented using the whole-process information method. The purpose of this study is to investigate the prevalence of myopia in urban and rural areas of Northeast China and to determine the factors related to myopia.

METHODS AND ANALYSIS

This is a school-based cross-sectional study. Our study population will include 6000 school-aged children from 2 urban and 2 rural schools in Jinzhou, China. The study will be conducted using our self-developed internet-based intelligent data collection, transmission, storage and analysis system. Examination parameters include uncorrected distance visual acuity, presenting distance visual acuity, non-cycloplegic autorefraction, height, weight, waist circumference, hip circumference, spinal curvature and dental caries. The examination report will be automatically sent to parents, who will complete the questionnaire, and appropriate statistical analysis will be performed. The main outcome is the prevalence of myopia, defined as an equivalent spherical degree ≤-0.5 D.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Third Affiliated Hospital of Jinzhou Medical University (number: JYDSY-KXYJ-IEC-2023-018). Findings will be published in a peer-reviewed journal. Subjects and their parents (or other authorised agents) give informed consent prior to study participation.

TRIAL REGISTRATION NUMBER

ChiCTR2300072893.

Efficacy of the DRL orthokeratology lens in slowing axial elongation in French children

Background

This study aims to assess and compare the impact of Orthokeratology Double Reservoir Lens (DRL) versus Single Vision Lenses (SVL) on axial elongation and anterior chamber biometric parameters in myopic children over a 6- and 12-month treatment period in France.

Methods

A retrospective study involving 48 patients aged 7 to 17 years, who underwent either orthokeratology treatment or single-vision spectacle correction, was conducted. Changes in refractive error, axial length, and anterior chamber depth were examined.

Results

Twenty-five patients comprised the Orthokeratology (OK) group, while twenty-three were in the control group (single-vision spectacle group). Significant increases in mean axial length were observed over time in both the control (0.12 ± 0.13 mm and 0.20 ± 0.17 mm after 6 and 12 months, respectively; F (2,28.9) = 27.68, p < 0.001) and OK groups (0.02 ± 0.07 mm and 0.06 ± 0.13 mm after 6 and 12 months, respectively; F (2,29.1) = 5.30, p = 0.023). No statistically significant differences in axial length were found between male and female children (p > 0.620). Age-specific analysis revealed no significant axial elongation after 12 months in the 14-17 years group in the OK group. Anterior biometric data analysis at 6 and 12 months showed statistical significance only for the DRL group.

Conclusion

Orthokeratology resulted in an 86 and 70% reduction in axial elongation after 6 and 12 months of lens wear, respectively, compared to the single-vision spectacles group. Myopia progression was more pronounced in younger children, underscoring the importance of initiating myopia control strategies at early ages.

Spatial epidemiological characteristics and driving factors of myopia among school-age children based on geographical detector: a national study

The present study aimed to examine the spatial characteristics of myopia and identify the socioeconomic and environmental factors influencing its prevalence. Myopia prevalence among children of school age of Han ethnicity in China was 56.6% in 2019, with the highest and lowest prevalence's in Shandong (66.8%) and Guizhou (47.3%), respectively. There was a spatial aggregation of myopia prevalence in China. Environmental factors (atmospheric PM2.5 concentration and forest coverage) and socioeconomic factors (gross domestic product per capita, per capita disposable income, hospital beds per thousand people, and Engel coefficient) have significant influences on myopia prevalence. The interaction of each factor on myopia showed nonlinear enhancement. Myopia prevalence among children of school age was spatially clustered, and environmental and socioeconomic conditions are associated with myopia prevalence. Our findings provide novel perspectives for the comprehensive prevention and control of myopia.

Cost-Effectiveness Analysis of Myopia Progression Interventions in Children

Importance

Several interventions exist for treating myopia progression in children. While these interventions' efficacy has been studied, their cost-effectiveness remains unknown and has not been compared.

Objective

To determine cost-effective options for controlling myopia progression in children.

Design, Setting, and Participants

In this cost-effectiveness analysis, a Markov model was designed to compare the cost-effectiveness of interventions for controlling myopia progression over 5 years from a societal perspective in a simulated hypothetical cohort of patients aged 10 years with myopia. Myopia interventions considered included atropine eye drops, 0.05% and 0.01%, defocus incorporated multiple segment spectacles, outdoor activity, soft contact lenses (daily disposable and multifocal), rigid gas-permeable contact lenses, progressive addition lenses, bifocal spectacle lenses, orthokeratology, highly aspherical lenslets (HALs), and red light therapy; all interventions were compared with single-vision lenses. Deterministic and probabilistic sensitivity analysis determined the association of model uncertainties with the cost-effectiveness. Costs were obtained from the charges of the Hospital Authority of Hong Kong and The Chinese University of Hong Kong Eye Center.

Main Outcome and Measures

The mean costs (in US dollars) per child included the cost of hospital visits, medications, and optical lenses. The outcomes of effectiveness were the annual spherical equivalent refraction (SER) and axial length (AL) reductions. Incremental cost-effectiveness ratios (ICERs) were calculated for each strategy relative to single-vision lenses over a time horizon of 5 years.

Results

Outdoor activity, atropine (0.05%), red light therapy, HALs, and orthokeratology were cost-effective. The ICER of atropine, 0.05%, was US $220/SER reduction; red light therapy, US $846/SER reduction; and HALs, US $448/SER reduction. Outdoor activity yielded a savings of US $5/SER reduction and US $8/AL reduction. Orthokeratology resulted in an ICER of US $2376/AL reduction.

Conclusions and Relevance

These findings suggest that atropine eye drops, 0.05%, and outdoor activity are cost-effective for controlling myopia progression in children. Though more expensive, red light therapy, HALs, and orthokeratology may also be cost-effective. The use of these interventions may help to control myopia in a cost-effective way.

Comparing the effects of highly aspherical lenslets versus defocus incorporated multiple segment spectacle lenses on myopia control

To compare spectacle lenses with highly aspherical lenslets (HAL) versus defocus incorporated multiple segments (DIMS) on myopia progression control in 1 year. This retrospective cohort study involved data from children prescribed HAL or DIMS spectacle lenses in Guangzhou Aier Eye Hospital, China. To address the discrepancy that some children followed up at less than or more than 1 year, the standardized 1-year spherical equivalent refraction (SER) and axial length (AL) changes from baseline were calculated. The mean differences in the changes between the two groups were compared with linear multivariate regression models. Age, sex, baseline SER/AL, and treatment were included in the models. A total of 257 children who qualified for the inclusion criteria were included for the analyses (193 in the HAL group and 64 in the DIMS group). After controlling baseline variates, the adjusted mean (standard error, SE) of the standardized 1-year changes in SER for HAL and DIMS spectacle lens users were - 0.34 (0.04) D and - 0.63 (0.07) D, respectively. HAL spectacle lenses reduced myopia progression by 0.29 D (95% confidence interval [CI] 0.13 to 0.44 D) at 1 year compared to DIMS lenses. Accordingly, the adjusted mean (SE) ALs increased by 0.17 (0.02) and 0.28 (0.04) mm for children wearing HAL lenses and DIMS lenses, respectively. HAL users had 0.11 mm less AL elongation (95% CI - 0.20 to - 0.02 mm) than DIMS users. Age at baseline was significantly associated with AL elongation. Chinese children wearing spectacle lenses designed with HAL had less myopia progression and axial elongation than those wearing spectacle lenses designed with DIMS.

Interventions for myopia control in children: a living systematic review and network meta-analysis

BACKGROUND

Myopia is a common refractive error, where elongation of the eyeball causes distant objects to appear blurred. The increasing prevalence of myopia is a growing global public health problem, in terms of rates of uncorrected refractive error and significantly, an increased risk of visual impairment due to myopia-related ocular morbidity. Since myopia is usually detected in children before 10 years of age and can progress rapidly, interventions to slow its progression need to be delivered in childhood.

OBJECTIVES

To assess the comparative efficacy of optical, pharmacological and environmental interventions for slowing myopia progression in children using network meta-analysis (NMA). To generate a relative ranking of myopia control interventions according to their efficacy. To produce a brief economic commentary, summarising the economic evaluations assessing myopia control interventions in children. To maintain the currency of the evidence using a living systematic review approach.  SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register), MEDLINE; Embase; and three trials registers. The search date was 26 February 2022.  SELECTION CRITERIA: We included randomised controlled trials (RCTs) of optical, pharmacological and environmental interventions for slowing myopia progression in children aged 18 years or younger. Critical outcomes were progression of myopia (defined as the difference in the change in spherical equivalent refraction (SER, dioptres (D)) and axial length (mm) in the intervention and control groups at one year or longer) and difference in the change in SER and axial length following cessation of treatment ('rebound').  DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods. We assessed bias using RoB 2 for parallel RCTs. We rated the certainty of evidence using the GRADE approach for the outcomes: change in SER and axial length at one and two years. Most comparisons were with inactive controls.

MAIN RESULTS

We included 64 studies that randomised 11,617 children, aged 4 to 18 years. Studies were mostly conducted in China or other Asian countries (39 studies, 60.9%) and North America (13 studies, 20.3%). Fifty-seven studies (89%) compared myopia control interventions (multifocal spectacles, peripheral plus spectacles (PPSL), undercorrected single vision spectacles (SVLs), multifocal soft contact lenses (MFSCL), orthokeratology, rigid gas-permeable contact lenses (RGP); or pharmacological interventions (including high- (HDA), moderate- (MDA) and low-dose (LDA) atropine, pirenzipine or 7-methylxanthine) against an inactive control. Study duration was 12 to 36 months. The overall certainty of the evidence ranged from very low to moderate. Since the networks in the NMA were poorly connected, most estimates versus control were as, or more, imprecise than the corresponding direct estimates. Consequently, we mostly report estimates based on direct (pairwise) comparisons below. At one year, in 38 studies (6525 participants analysed), the median change in SER for controls was -0.65 D. The following interventions may reduce SER progression compared to controls: HDA (mean difference (MD) 0.90 D, 95% confidence interval (CI) 0.62 to 1.18), MDA (MD 0.65 D, 95% CI 0.27 to 1.03), LDA (MD 0.38 D, 95% CI 0.10 to 0.66), pirenzipine (MD 0.32 D, 95% CI 0.15 to 0.49), MFSCL (MD 0.26 D, 95% CI 0.17 to 0.35), PPSLs (MD 0.51 D, 95% CI 0.19 to 0.82), and multifocal spectacles (MD 0.14 D, 95% CI 0.08 to 0.21). By contrast, there was little or no evidence that RGP (MD 0.02 D, 95% CI -0.05 to 0.10), 7-methylxanthine (MD 0.07 D, 95% CI -0.09 to 0.24) or undercorrected SVLs (MD -0.15 D, 95% CI -0.29 to 0.00) reduce progression.  At two years, in 26 studies (4949 participants), the median change in SER for controls was -1.02 D. The following interventions may reduce SER progression compared to controls: HDA (MD 1.26 D, 95% CI 1.17 to 1.36), MDA (MD 0.45 D, 95% CI 0.08 to 0.83), LDA (MD 0.24 D, 95% CI 0.17 to 0.31), pirenzipine (MD 0.41 D, 95% CI 0.13 to 0.69), MFSCL (MD 0.30 D, 95% CI 0.19 to 0.41), and multifocal spectacles  (MD 0.19 D, 95% CI 0.08 to 0.30). PPSLs (MD 0.34 D, 95% CI -0.08 to 0.76) may also reduce progression, but the results were inconsistent. For RGP, one study found a benefit and another found no difference with control. We found no difference in SER change for undercorrected SVLs (MD 0.02 D, 95% CI -0.05 to 0.09). At one year, in 36 studies (6263 participants), the median change in axial length for controls was 0.31 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD -0.33 mm, 95% CI -0.35 to 0.30), MDA (MD -0.28 mm, 95% CI -0.38 to -0.17), LDA (MD -0.13 mm, 95% CI -0.21 to -0.05), orthokeratology (MD -0.19 mm, 95% CI -0.23 to -0.15), MFSCL (MD -0.11 mm, 95% CI -0.13 to -0.09), pirenzipine (MD -0.10 mm, 95% CI -0.18 to -0.02), PPSLs (MD -0.13 mm, 95% CI -0.24 to -0.03), and multifocal spectacles (MD -0.06 mm, 95% CI -0.09 to -0.04). We found little or no evidence that RGP (MD 0.02 mm, 95% CI -0.05 to 0.10), 7-methylxanthine (MD 0.03 mm, 95% CI -0.10 to 0.03) or undercorrected SVLs (MD 0.05 mm, 95% CI -0.01 to 0.11) reduce axial length. At two years, in 21 studies (4169 participants), the median change in axial length for controls was 0.56 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD -0.47mm, 95% CI -0.61 to -0.34), MDA (MD -0.33 mm, 95% CI -0.46 to -0.20), orthokeratology (MD -0.28 mm, (95% CI -0.38 to -0.19), LDA (MD -0.16 mm, 95% CI -0.20 to  -0.12), MFSCL (MD -0.15 mm, 95% CI -0.19 to -0.12), and multifocal spectacles (MD -0.07 mm, 95% CI -0.12 to -0.03). PPSL may reduce progression (MD -0.20 mm, 95% CI -0.45 to 0.05) but results were inconsistent. We found little or no evidence that undercorrected SVLs (MD -0.01 mm, 95% CI -0.06 to 0.03) or RGP (MD 0.03 mm, 95% CI -0.05 to 0.12) reduce axial length. There was inconclusive evidence on whether treatment cessation increases myopia progression. Adverse events and treatment adherence were not consistently reported, and only one study reported quality of life. No studies reported environmental interventions reporting progression in children with myopia, and no economic evaluations assessed interventions for myopia control in children.

AUTHORS' CONCLUSIONS

Studies mostly compared pharmacological and optical treatments to slow the progression of myopia with an inactive comparator. Effects at one year provided evidence that these interventions may slow refractive change and reduce axial elongation, although results were often heterogeneous. A smaller body of evidence is available at two or three years, and uncertainty remains about the sustained effect of these interventions. Longer-term and better-quality studies comparing myopia control interventions used alone or in combination are needed, and improved methods for monitoring and reporting adverse effects.

Characteristics of full compensation and its association with total astigmatism: A cross-sectional study

Objective

To evaluate the characteristics of full compensation and its association with the prevalence of total astigmatism (TA), and to analyze the effects of TA on uncorrected distance visual acuity (UDVA).

Methods

With random cluster sampling based on a school-based cross-sectional design, children aged 4 to 18 years were recruited in September 2020, Shandong Province, China. TA, anterior corneal astigmatism (ACA), and ocular residual astigmatism (ORA) were converted to vectorial components (J0, J45), followed by an assessment of the compensatory effect of ACA by ORA. Astigmatism was defined as a cylinder that was better than or equal to 0.75 diopters (D). Logistic regression analysis was used to assess the related factors for children with full compensation, and the generalized linear model was used to assess the influence of TA on UDVA.

Results

Out of 4,494 eligible children, data of 4,145 children (92.3%, 9.23 ± 3.15 years, 50.4% boys) were included in the statistical analysis. The prevalence of TA (27.9%) increased significantly with age (P_trend < 0.001). The distribution of full compensation in J0 and J45 components were similar (22.1% and 25.6%, respectively), which decreased with age (P_trend < 0.001). The closer the refractive status was to emmetropization, the higher the proportion of full compensation and the lower the prevalence of TA were. Shorter axial length (J0: Odds Ratio (OR) = 0.76, 95% confidence interval (CI): 0.61 to 0.94, P = 0.010), better UDVA (J0: OR = 0.37, 95% CI: 0.21 to 0.65, P < 0.001; J45: OR = 0.34, 95% CI: 0.20 to 0.59, P < 0.001), and longer average corneal curvature radius (J0: OR = 3.72, 95% CI: 2.18 to 6.34, P < 0.001; J45: OR = 2.82, 95% CI: 1.67 to 4.76, P < 0.001) were associated with full compensation. Higher TA was associated with a worse UDVA (β = 0.03, 95% CI: 0.02 to 0.04, P < 0.001).

Conclusions

The prevalence of TA gradually increased with age, and showed a U-shaped distribution with increased refraction. Full compensation was associated with smaller TA and better UDVA. This indicated that considering the compensatory effect of ORA is vital for astigmatism correction in clinical work, which may improve the visual quality.

Cost-effectiveness analysis of myopia management: A systematic review

The rising prevalence of myopia is a major global public health concern. Economic evaluation of myopia interventions is critical for maximizing the benefits of treatment and the healthcare system. This systematic review aimed to evaluate the cost-effectiveness of interventions for treating myopia. Five databases were searched - Embase, Emcare, PubMed, Web of Science, and ProQuest - from inception to July 2022 and a total of 2,099 articles were identified. After careful assessments, 6 studies met the eligibility criteria. The primary outcomes of this systematic review were costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). The secondary outcomes included utility values and net monetary benefits (NMB). One study determined the cost-effectiveness of photorefractive screening plus treatment with 0.01% atropine, 2 studies examined cost-effectiveness of corneal refractive surgery, and 3 studies evaluated cost-effectiveness of commonly used therapies for pathologic myopia. Corneal refractive surgeries included laser in situ keratomileusis (LASIK), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), photorefractive keratectomy (PRK), and small-incision lenticule extraction (SMILE). Interventions for pathologic myopia included ranibizumab, conbercept, and photodynamic therapy (PDT). At an incremental cost of NZ$ 18 (95% CI 15, 20) (US$ 11) per person, photorefractive screening plus 0.01% atropine resulted in an ICER of NZ$ 1,590/QALY (US$ 1,001/QALY) (95% CI NZ$ 1,390, 1,791) for an incremental QALY of 0.0129 (95% CI 0.0127, 0.0131). The cost of refractive surgery in Europe ranged from €3,075 to €3,123 ([US$4,046 to $4,109 - adjusted to 2021 inflation). QALYs associated with these procedures were 23 (FS-LASIK) and 24 (SMILE and PRK) with utility values of 0.8 and ICERs ranging from approximately €14 (US$17)/QALY to €19 (US$23)/QALY. The ICER of LASIK was US$683/diopter gained (inflation-adjusted). The ICER of ranibizumab and PDT were £8,778 (US$12,032)/QALY and US$322,460/QALY respectively, with conbercept yielding a saving of 541,974 RMB (US$80,163)/QALY, respectively. The use of 0.01% atropine and corneal refractive surgery were cost-effective for treating myopia. Treating pathologic myopia with ranibizumab and conbercept were more cost-effective than PDT. Prevention of myopia progression is more cost-effective than treating pathologic myopia.

Eye Habits Affect the Prevalence of Asthenopia in Patients with Myopia

Purpose

This study aims to explore the risk factors of asthenopia in the myopic population.

Methods

In this cross-sectional study, myopia patients were inquired about their eye habits and were requested to complete an asthenopia questionnaire and ocular examinations. Age, gender, occupation, anisometropia, eye care education, weekly outdoor activity time, duration of continuous near work, daily screen time, dry eye, near phoria, and binocular accommodative facility were calculated using the Student's test-test, Mann Whitney U test, and Pearson's chi-square test. Spherical equivalents and astigmatism were calculated using a generalized estimating equation. Binary logistic regression was performed on factors with a p-value <0.05.

Results

Of the 65 myopic patients, 57% showed asthenopia, 52% experienced blurry vision, 37% felt their eyes hurt or sore, and 28% felt tired when performing close work. Asthenopia patients were older than patients without asthenopia (Z = −2.887, p=0.004). Daily screen time, continuous near-work time, eye care education, and dry eye were positively correlated with asthenopia (χ² = 8.64, p=0.003; χ2 = 13.873, p < 0.001, χ2 = 9.643, p=0.002; χ2 = 7.035, p=0.008). After eliminating collinearity, eye care education and continuous near-work time were identified as independent risk factors of asthenopia, with odds ratios of 0.115 and 4.227, respectively.

Conclusion

This study shows that receiving eye care education from schools and hospitals and limiting near-work duration to less than 45 minutes per session could reduce the occurrence of asthenopia in myopic patients. This approach may be a more economical and convenient way for myopic people to relieve asthenopia.

Will treating progressive myopia overwhelm the eye care workforce? A workforce modelling study

Purpose

Treatments for myopia progression are now available, but implementing these into clinical practice will place a burden on the eye care workforce. This study estimated the full‐time equivalent (FTE) workforce required to implement myopia control treatments in the UK and Ireland.

Methods

To estimate the number of 6‐ to 21‐year‐olds with myopia, two models utilising separate data sources were developed. The examination‐based model used: (1) the number of primary care eye examinations conducted annually and (2) the proportion of these that are for myopic young people. The prevalence‐based model used epidemiological data on the age‐specific prevalence of myopia. The proportion of myopic young people progressing ≥0.25 dioptres (D)/year or ≥0.50 D/year was obtained from Irish electronic health records and the recommended review schedule from clinical management guidelines.

Results

Using the examination and prevalence models, respectively, the estimated number of young people with myopia was 2,469,943 and 2,235,713. The extra workforce required to provide comprehensive myopia management for this target population was estimated at 226–317 FTE at the 0.50 D/year threshold and 433–630 FTE at the 0.25 D/year threshold. Extra visits required for myopia control treatment represented approximately 2.6% of current primary eye care examinations versus 13.6% of hospital examinations.

Conclusions

Implementing new myopia control treatments in primary care settings over the medium‐term is unlikely to overwhelm the eye care workforce completely. Further increases to workforce, upskilling of current workforce and tools to reduce chair time will help to ensure sustainability of the eye care workforce into the future.

Longitudinal Changes in Refractive Error Among Preschool Children Aged 1–6 Years: The Changsha Children Eye Study

Purpose

To investigate the longitudinal changes in refractive error of preschool children and explore the factors related to these changes and the timing of intervention.

Methods

The refractive data of preschool children aged 1–6 years were collected from 16 community Health Service Centers in Changsha during April 2016 to July 2019 for the retrospective cohort study. The refractive data of each participant was measured with a hand-held vision screener without cycloplegia. A follow-up for all the included participants was performed. The spherical equivalent change was calculated, subsequently, an analysis of risk factors related to the change was performed.

Results

Four thousand nine hundred twenty-one cases were included in the study with the follow-up for 1–2 years. The refractive status was found smoothly changed in 67.8% of children. The overall initial SE was 0.62 ± 1.13 D, and the average SE change was −0.20 ± 1.23 D per year. However, profound myopic shift was observed in 32.2% of children. The change of SE in 3-year-old group is most overt. The proportions of 1–6 years old who showed moderate and severe myopic shift (SE change ≥–1.00 D) were 21.6, 18.9, 28.2, 25.5, 13.4, and 10%, respectively. At the first visit, the younger children with greater hyperopic state exhibited more noticeable myopic shift, no significant difference was found in gender.

Conclusion

The shift from hyperopia to myopia in preschool children is smooth, with −0.20D change on average per year. We suggest that an optometry screening should start at 3-year-old to track children's refractive status. We recommend that preschool children whose SE changes more than −1.00 D per year go to the ophthalmology department for further examination. Our study also found that at the first visit, the younger the child is and the more positive initial SE is, the degree of shift of myopia is greater.

Healthcare utilization and economic burden of myopia in urban China: A nationwide cost-of-illness study

Background

China contributes to a significant proportion of the myopia in the world. The study aims to investigate the utilization of various correction methods and health service in urban China, and to estimate the cost of myopia treatment and prevention. In addition, we aimed to estimate the cost of productivity loss due to myopia.

Methods

The study was a cross-sectional investigation carried out in urban areas in three provinces located in the east (Shanghai), middle (Anhui) and west part (Yunnan) of China, in 2016. A total of 23819 people aged between 5 to 50 years were included. Health utilization and the cost of myopia were analyzed from patients’ perspective.

Results

The total number of people with myopia in the urban China was estimated to be 143.6 million. The correction rate was 89.5%, 92.1%, and 92.7% for Anhui, Shanghai, and Yunnan (χ² = 19.5, P < 0.01). Over the recent year, 20.6%, 16.8%, and 28.8% of myopic subjects visited hospital due to myopia, in Anhui, Shanghai and Yunnan. The annual cost of treatment and prevention of myopia was 10.1 billion US dollar (US$, floating from 9.2 to 11.2 billion US$), and the cost per person was 69US$. The annual cost of loss of productivity was estimated to be 6.7 billion US$ for those with mild to moderate visual impairment (floating from 6.1 to 7.4 billion US$), and 9.4 billion US$ (floating from 8.5 to 10.4 billion US$) for those with severe visual impairment to blindness. Therefore, the total economic burden of myopia was estimated as 173.6 billion CNY (26.3 billion US$).

Conclusions

The present study shows that myopia leads to substantial economic burden in China. The loss of productivity caused by myopia is an important part of the disease burden compared to the cost of correction and treatment paid by individuals. Therefore, the focus of myopia prevention and control should be to decrease the myopia prevalence, and prevent the uncorrected refractive errors and the irreversible damage of visual acuity by high myopia.

Time spent outdoors as an intervention for myopia prevention and control in children: an overview of systematic reviews

PURPOSE

Outdoor light exposure is considered a safe and effective strategy to reduce myopia development and aligns with existing public health initiatives to promote healthier lifestyles in children. However, it is unclear whether this strategy reduces myopia progression in eyes that are already myopic. This study aims to conduct an overview of systematic reviews (SRs) reporting time spent outdoors as a strategy to prevent myopia or slow its progression in children.

METHODS

We searched the Cochrane Library, EMBASE, MEDLINE and CINAHL from inception to 1 November 2020 to identify SRs that evaluated the association between outdoor light exposure and myopia development or progression in children. Outcomes included incident myopia, prevalent myopia and change in spherical equivalent refraction (SER) and axial length (AL) to evaluate annual rates of myopia progression. The methodological quality and risk of bias of included SRs were assessed using the AMSTAR-2 and ROBIS tools, respectively.

RESULTS

Seven SRs were identified, which included data from 47 primary studies with 63,920 participants. Pooled estimates (risk or odds ratios) consistently demonstrated that time outdoors was associated with a reduction in prevalence and incidence of myopia. In terms of slowing progression in eyes that were already myopic, the reported annual reductions in SER and AL from baseline were small (0.13-0.17 D) and regarded as clinically insignificant. Methodological quality assessment using AMSTAR-2 found that all reviews had one or more critical flaws and the ROBIS tool identified a low risk of bias in only two of the included SRs.

CONCLUSION

This overview found that increased exposure to outdoor light reduces myopia development. However, based on annual change in SER and AL, there is insufficient evidence for a clinically significant effect on myopia progression. The poor methodological quality and inconsistent reporting of the included systematic reviews reduce confidence in the estimates of effect.

How to Conduct School Myopia Screening: Comparison Among Myopia Screening Tests and Determination of Associated Cutoffs

PURPOSE

To compare the accuracy for various screening tests and their combined uses for myopia screening among children and adolescents and explore age-specific cutoffs.

DESIGN

Cross-sectional study.

METHODS

A total of 6017 children and adolescents aged 4 to 15 years participated in the study. Uncorrected visual acuity (UCVA, recorded in decimal notation), cycloplegic and noncycloplegic refraction (NCR), axial length (AL), and corneal curvature radius (CR) examinations were performed. Cycloplegic spherical equivalent ≤-0.50 D was considered as the gold standard for myopia. Receiver operating characteristic (ROC) curves were drawn to determine optimal cutoffs for all age groups, and sensitivity, specificity, as well as screening prevalence of myopia were calculated.

RESULTS

The overall estimate of myopia prevalence was 31.8% using the gold standard. The sensitivity and specificity of the UCVA alone for the commonly used cutoff (1.0) were 97.7% and 33.1%, respectively. The areas under the ROC curve were optimally estimated to be 0.985 (95% CI, 0.982-0.988) for the combined use of UCVA and NCR tests, and 0.987 (95% CI, 0.983-0.989) for the combined use of AL/CR and NCR tests, with no significant difference (P = 0.208). The best cutoffs for UCVA-NCR combinations were UCVA <1.0 and NCR <-0.25 D in 4 to 6 years; UCVA <1.0 and NCR <-0.50 D in 7 to 12 years; UCVA <0.8 and NCR <-0.75 D in 13 to 15 years. If those screening positive were all referred to clinics and corrected with cycloplegic autorefraction data, the relative difference between screening prevalence and the actual prevalence by the gold standard would reduce from 13.2% to 4.7%.

CONCLUSIONS

UCVA test alone for detecting myopia demonstrated a poorer accuracy among these tests. The combined use of UCVA and NCR tests and the combined use of AL/CR and NCR tests achieved optimal accuracy for myopia screening. Setting age-specific cutoffs would increase the accuracy, and the prevalence obtained from primary screening should be corrected according to the data of cycloplegic refraction after referral, especially in younger ages.

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.

The influence of the choroid on the onset and development of myopia: from perspectives of choroidal thickness and blood flow

Myopia is the most common type of refractive errors characterized by excessive elongation of the ocular globe. With the increasing prevalence of myopia, improved knowledge of factors involved in myopia development is of particular importance. There are growing evidence suggesting that the choroid plays an important role in the regulation of eye growth and the development of myopia. Studies have demonstrated that thinning choroid is a structural feature of myopia, with a negative correlation between choroidal thickness and axial length, suggesting that the change in choroidal thickness may be a predictive biomarker for long-term changes in ocular elongation. Given the fact that the choroid is primarily a vascular structure capable of rapidly changing blood flow, variations of choroidal thickness might be primarily caused by changes in choroidal blood flow. Considering that hypoxia is associated with myopia and choroidal blood flow is the main source of oxygen and nourishment supply, apart from the effect on myopia possibly by changing choroidal thickness, decreasing choroidal blood flow may contribute to scleral ischaemia and hypoxia, resulting in alterations in the scleral structure and thus leading to myopia. This review aims to provide an overview of recent work exploring the influence of the choroid on myopia from perspectives of choroidal thickness and blood flow, which may present new predictive indicators for the onset of myopia and new targets for the development of novel therapeutic approaches for myopia.

Risk factors for rapid axial length elongation with low concentration atropine for myopia control

Three hundred and twenty-eight myopic children, randomized to use either 0.01% (N = 166) or 0.02% (N = 162) atropine were enrolled in this study. Gender, age, body mass index(BMI), parental myopia status, atropine concentration used, pupil diameter, amplitude of accommodation, spherical equivalent refractive error (SER), anterior chamber depth (ACD) and axial length (AL) were collected at baseline and 1 year after using atropine. Rapid AL elongation was defined as > 0.36 mm growth per year. Univariate analyses showed that children with rapid AL elongation tend to be younger, have a smaller BMI, use of 0.01% atropine, narrow ACD, lower SER, shorter AL, smaller change in pupil diameter between 1 year and baseline (all P < 0.05). Multivariate logistic regression analyses confirmed that rapid AL elongation was associated with children that were younger at baseline (P < 0.0001), use of 0.01% atropine (P = 0.04), a shorter baseline AL (P = 0.03) and a smaller change in pupil diameter between 1 year and baseline (P = 0.04). Younger children with shorter AL at baseline, less change in their pupil diameter with atropine treatment and using the lower of the two atropine concentrations may undergo rapid AL elongation over a 12 months myopia control treatment period.

IMI Impact of Myopia

The global burden of myopia is growing. Myopia affected nearly 30% of the world population in 2020 and this number is expected to rise to 50% by 2050. This review aims to analyze the impact of myopia on individuals and society; summarizing the evidence for recent research on the prevalence of myopia and high myopia, lifetime pathological manifestations of myopia, direct health expenditure, and indirect costs such as lost productivity and reduced quality of life (QOL). The principal trends are a rising prevalence of myopia and high myopia, with a disproportionately greater increase in the prevalence of high myopia. This forecasts a future increase in vision loss due to uncorrected myopia as well as high myopia-related complications such as myopic macular degeneration. QOL is affected for those with uncorrected myopia, high myopia, or complications of high myopia. Overall the current global cost estimates related to direct health expenditure and lost productivity are in the billions. Health expenditure is greater in adults, reflecting the added costs due to myopia-related complications. Unless the current trajectory for the rising prevalence of myopia and high myopia change, the costs will continue to grow. The past few decades have seen the emergence of several novel approaches to prevent and slow myopia. Further work is needed to understand the life-long impact of myopia on an individual and the cost-effectiveness of the various novel approaches in reducing the burden.

Under-correction or full correction of myopia? A meta-analysis

PURPOSE

To compare the effect of full-correction versus under-correction on myopia progression.

METHODS

A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality assessment of the literature was evaluated according to the Critical Appraisal Skills Program. Statistical analysis was performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA).

RESULTS

The present meta-analysis included six studies (two randomized controlled trials [RCTs] and four non-RCTs) with 695 subjects (full-correction group, n=371; under-correction group, n=324) aged 6 to 33 years. Using cycloplegic refraction, the pooled difference in mean of myopia progression was - 0.179 D [lower and higher limits: -0.383, 0.025], which was higher but not in full correction group as compared to under correction group (p=0.085). Regarding studies using non-cycloplegic subjective refraction according to maximum plus for maximum visual acuity, the pooled difference in myopia progression was 0.128 D [lower and higher limits: -0.057, 0.312] higher in under-correction group compared with full-correction group (p=0.175). Although, difference in myopia progression did not reach significant level in either cycloplegic or non-cycloplegic refraction.

CONCLUSIONS

Our findings suggest that, myopic eyes which are fully corrected with non-cycloplegic refraction with maximum plus sphere, are less prone to myopia progression, in comparison to those which were under corrected. However, regarding cycloplegic refraction, further studies are needed to better understand these trends.

Sleep Duration, Bedtime, and Myopia Progression in a 4-Year Follow-up of Chinese Children: The Anyang Childhood Eye Study

Purpose

To investigate the relationship between sleep duration and bedtime with myopia progression and axial elongation during a 4-year follow-up in primary school children.

Methods

This study included 1887 children (aged 7.09 ± 0.41 years) who had cycloplegic refractions data at baseline and a fourth visit and 2209 children (aged 7.10 ± 0.41 years) for axial length. All children underwent comprehensive ophthalmologic examinations, including cycloplegic refraction and ocular biometry, and standardized questionnaires, including average night-time sleep duration (h/d) and bedtime (time to bed). Myopia was defined as spherical equivalent < –0.5 diopters.

Results

At the last follow-up, the mean myopia progression and axial elongation for all children were –1.89 ± 1.28 diopters and 1.22 ± 0.57 mm. After stratifying the sleep duration into tertile groups, myopia progression and axial elongation were slower in children with highest sleep duration tertile (P = 0.04 and P =0.014) in girls but not in boys, compared with the middle sleep duration tertile. However, after adjusting for potential confounders, no significant association was found for sleep duration with myopia progression and axial elongation for the children (P = 0.255 and P = 0.068), and the association with axial elongation was only of borderline significance in girls (P = 0.045). The bedtime was not associated with myopia progression and axial elongation in the regression analyses (P = 0.538; P = 0.801).

Conclusions

These results show that there was no significant association between sleep duration and bedtime with myopia progression and axial elongation among children. The findings in girls might be related to the earlier onset of puberty.

Myopia and its progression in children in London, UK: a retrospective evaluation

PURPOSE

Worldwide, the prevalence of myopia is increasing. Myopia begins at younger ages and progresses faster, leading to more adults with high myopia and risk of sight-threatening complications. No data are available about myopia trends in children in urban areas in the UK. We present a 10-year review of children attending a secondary and tertiary eye care facility in London, focussing on the proportion of glasses prescriptions for myopia and progression rates.

METHODS

We collated refraction and demographic data from children under the age of 17 years seen at Moorfields Eye Hospital, London, UK, between 2008 and 2017.

RESULTS

We included 63,854 datasets from 23,593 children (51.2% boys, median age 5.4 years, interquartile range IQR 3.8-7.1). The proportion of myopic prescriptions increased from 24 to 32%. In n = 3355 with initial mild/moderate myopia, median progression rate was -0.16 (-0.5 to 0.04) D/year. In those with progression (n = 2095), the rate was -0.40 (-0.19 to -0.74) D/year, slightly higher in girls than in boys (-0.42 vs -0.38 D/year; p = 0.02). Progression was faster in initial moderate than initial mild myopia (-0.54 vs -0.37 D/year; p < 0.001), and before than after average age of onset of puberty (-0.41 vs -0.35 D/year; p = 0.013). There was no statistically significant difference between children of different ethnic backgrounds.

CONCLUSIONS

In this cohort, the proportion of glasses prescriptions for myopia and the rate of progression are higher than previously reported for European countries. Living in an urban environment may result in similar progression rates despite different genetic backgrounds.

Protective effects of increased outdoor time against myopia: a review

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

The Effect of Treatment Zone Decentration on Myopic Progression during Or-thokeratology

Purpose: To evaluate the relationship between magnitude of orthokeratology (OrthoK) treatment zone decentration and 2-year axial length (AL) elongation in myopic children.Methods: One-hundred and one Chinese children who wore OrthoK contact lenses for 2 years. The magnitude and direction of the OrthoK treatment zone center from the entrance pupil center were recorded after 3 and 24 months of lens wear along with AL measurement. Stepwise multiple linear regression analysis was performed to assess which factors significantly affected an increase in AL.Results: After 3 and 24 months of OrthoK treatment, the mean (± standard deviation [SD]) magnitude of the OrthoK treatment zone decentration was 0.64 ± 0.38 mm and 0.68 ± 0.32 mm, respectively. There were no significant differences between the two time points (P > .05). After 2 years of OrthoK contact lenses wear, the mean (± SD) AL growth was 0.36 ± 0.34 mm. The axial elongation was slightly correlated with baseline age of subjects (r = -0.073, P < .001), baseline spherical equivalent refractive error (r = -0.088, P < .001) and magnitude decentration of treatment zone (r = -0.190, P = .027).Conclusions: The decentration of OrthoK treatment zone stabilizes after 3 months of lens wear and slightly decreases AL growth.

Association between serum 25-hydroxyvitamin D levels and myopia in general Korean adults

Purpose

We performed this study to determine the association between serum 25-hydroxyvitamin D [25(OH) D] level and myopia in adults.

Methods

A total of 25,199 subjects aged ≥20 years were included from the National Health and Nutrition Examination Survey 2008-2012. Blood 25(OH)D levels were evaluated from blood samples. Refractive error was measured without cycloplegia. Myopia and high myopia were defined as ≥-0.50 diopters (D) and ≥-6.0 D, respectively. Other covariates such as education, physical activity, and economic status were obtained from interviews.

Results

Linear regression analysis showed that as 25(OH) D level increased by 1 ng/mL, myopic refractive error significantly decreased by 0.01 D (P < 0.001) after adjusting for potential confounders including sex, age, height, education level, economic status, physical activity, and sunlight exposure time. The odds ratios for myopia was 0.75 (95% Confidence interval [CI]; 0.67-0.84, P < 0.001) in the highest 25(OH) D quintile compared to the lowest quintile. The odds ratios for high myopia was 0.63 (95% CI; 0.47-0.85, P < 0.001) in the highest 25(OH)D quintile compared to the lowest quintile.

Conclusion

: Serum 25(OH)D level was inversely associated with myopia in Korean adults.

Dose-Response Relationship of Outdoor Exposure and Myopia Indicators: A Systematic Review and Meta-Analysis of Various Research Methods

Myopia in children has dramatically increased worldwide. A systematic review and meta-analysis were conducted to evaluate the effects of outdoor light exposure on myopia. According to research data from 13 studies of 15,081 children aged 4-14 at baseline, outdoor light exposure significantly reduced myopia incidence/prevalence (odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.80-0.91, p < 0.00001; I2 = 90%), spherical equivalent refractive error (SER) by 0.15 D/year (0.09-0.27, p < 0.0001), and axial elongation by 0.08 mm/year (-0.14 to -0.02, p = 0.02). The benefits of outdoor light exposure intervention, according to pooled overall results, included decreases in three myopia indicators: 50% in myopia incidence, 32.9% in SER, and 24.9% in axial elongation for individuals in Asia. Daily outdoor light exposure of more than 120 min was the most effective intervention, and weekly intervention time exhibited a dose-response relationship with all three indicators. Subgroup comparisons revealed that interventional studies report greater benefits from outdoor light exposure compared with cohort and cross-sectional studies, and individuals with myopia in intervention studies experienced slightly greater benefits than individuals without, in terms of SER and axial elongation. Therefore, this study suggests 120 min/day of outdoor light exposure at school.

Changes in Choroidal Thickness and Choroidal Blood Perfusion in Guinea Pig Myopia

Purpose

The purpose of this study was to study changes in choroidal thickness (ChT) and choroidal blood perfusion (ChBP), and the correlation between them, in guinea pig myopia.

Methods

The reliability of optical coherence tomography angiography (OCTA) for measuring ChT and ChBP was verified in guinea pigs, after cervical dislocation (n = 7) or temporal ciliary artery transection (n = 6). Changes in refraction, axial length, ChT, and ChBP were measured during spontaneous myopia (n = 9), monocular form-deprivation myopia (FDM, n = 13), or lens-induced myopia (LIM, n = 14), and after 4 days of recovery from FDM and LIM.

Results

The abolition (by cervical dislocation) or reduction (by temporal ciliary artery transection) of ChBP, and of the associated changes in ChT, were verified by OCTA, thus validating the method of measurement. In the spontaneous myopia group, ChT and ChBP were reduced by 25.2% and 31.9%, respectively. In FDM eyes, mean ± SD ChT and ChBP decreased significantly compared with the untreated fellow eyes (ChT fellow: 76.13 ± 9.34 μm versus 64.76 ± 11.15 μm for FDM; ChBP fellow: 37.87 ± 6.37 × 103 versus 30.27 ± 6.06 × 103 for FDM) and increased after 4 days of recovery (ChT: 77.94 ± 12.57 μm; ChBP: 37.41 ± 6.11 × 103). Effects of LIM were similar to those of FDM. Interocular differences in ChT and ChBP were significantly correlated in each group (FDM: R = 0.71, P < 0.001; LIM: R = 0.53, P < 0.001).

Conclusions

ChT and ChBP were significantly decreased in all three models of guinea pig myopia, and they both increased during recovery. Changes in ChT were positively correlated with changes in ChBP. Therefore, it is possible that the changes of ChT are responsible for the changes of ChBP or vice versa.

Retardation of Myopia Progression by Multifocal Soft Contact Lenses

Myopia is an important public health problem due to its prevalence and significant public health cost. Elevating levels of myopia increase the risk of vision impairment, and therefore, high myopia has become one of the main causes of untreatable vision loss throughout the world due to its irreversible complications. At present, many options for slowing progression of myopia have already been proposed and evaluated such as progressive addition of executive bifocal spectacle lenses, peripheral defocusing lenses, overnight orthokeratology, pharmacological agents such as atropine eye drops, and multifocal soft contact lenses (MFSCLs). Use of MFSCLs has especially increased in recent years due to the growing demand to slow myopia progression during patient's adolescent growth period to avoid pathological myopia in adulthood. Compared with the other traditional methods of controlling myopia, MFSCLs allow myopic patients to better maintain their clear visual quality and slow myopia progression. In this manuscript, we aim to review the basics of myopia, recent advances in contact lenses to control myopia with emphasis on MFSCLs, define the elements for proper MFSCL fittings (such as pupil size, aberrations, accommodation and centering), discuss the potential rebound effect after discontinuation of contact lenses, and future directions for improvements of contact lenses for the control of myopia.

A genetic risk score and number of myopic parents independently predict myopia

PURPOSE

To investigate whether a genetic risk score (GRS) improved performance of predicting refractive error compared to knowing a child's number of myopic parents (NMP) alone.

METHODS

This was a retrospective analysis of data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort study. Refractive error was assessed longitudinally between age 7-15 using non-cycloplegic autorefraction. Genetic variants (n = 149) associated with refractive error from a Consortium for Refractive Error And Myopia (CREAM) genome-wide association study were used to calculate a GRS for each child. Using refractive error at ages 7 and 15 years as the outcome variable, coefficient of determination (R² ) values were calculated via linear regression models for the predictors: NMP, GRS and a combined model.

RESULTS

Number of myopic parents was weakly predictive of refractive error in children aged 7 years, R²  = 3.0% (95% CI 1.8-4.1%, p < 0.0001) and aged 15 years, R²  = 4.8% (3.1-6.5%, p < 0.0001). The GRS was also weakly predictive; age 7 years, R²  = 1.1% (0.4-1.9%, p < 0.0001) and 15 years R²  = 2.6% (1.3-3.9%, p < 0.0001). Combining the 2 variables gave larger R² values at age 7, R²  = 3.7% (2.5-5.0%, p < 0.0001) and 15, R²  = 7.0% (5.0-9.0%, p < 0.0001). The combined model improved performance at both ages (both p < 0.0001).

CONCLUSION

A GRS improved the ability to detect children at risk of myopia independently of knowing the NMP. We speculate this may be because NMP captures information concerning environmental risk factors for myopia. Nevertheless, further gains are required to make such predictive tests worthwhile in the clinical environment.

Influence of severity and types of astigmatism on visual acuity in school-aged children in southern China

AIM

To investigate the influence of astigmatism on visual acuity in school-aged children, and to define a cutoff for clinically significant astigmatism.

METHODS

This is a population-based, cross-sectional study. Among 5053 enumerated children aged 5-15y in Guangzhou, 3729 (73.8%) children aged 7-15 with successful cycloplegic auto-refraction (1% cyclopentolate) and a reliable visual acuity measurement were included. Ocular measurement included external eye, anterior segment, media and fundus and cycloplegic auto-refraction. Primary outcome measures included the relationship between severity and subtypes of astigmatism and the prevalence of visual impairment. Three criteria for visual impairment were adopted: best-corrected visual acuity (BCVA) ≤0.7, uncorrected visual acuity (UCVA) ≤0.5 or <0.7 in the right eye.

RESULTS

Increases of cylinder power was significantly associated with worse visual acuity (UCVA: β=0.051, P<0.01; BCVA: β=0.025, P<0.001). A substantial increase in UCVI and BCVI was seen with astigmatism of 1.00 diopter (D) or more. Astigmatism ≥1.00 D had a greater BCVI prevalence than cylinder power less than 1.00 D (OR=4.20, 95%CI: 3.08-5.74), and this was also true for hyperopic, emmetropic and myopic refraction categories. Oblique astigmatism was associated with a higher risk of BCVI relative to with the rule astigmatism in myopic refractive category (OR=12.87, 95%CI: 2.20-75.38).

CONCLUSION

Both magnitude and subtypes of astigmatism influence the prevalence of visual impairment in school children. Cylinder ≥1.00 D may be useful as a cutoff for clinically significant astigmatism.

The measurement of time spent outdoors in child myopia research: a systematic review

The purpose of this article is to summarize the methods most commonly used to measure time spent outdoors and provide a comprehensive review of time and activity recording methods with the aim of encouraging the development of new methods. PubMed, Embase and the Cochrane Library were searched from Jan. 1^st, 1990 to Aug. 31^th, 2017. Studies including the following specific terms: "outdoor", "outside", "outdoor activity", "outside activity", "outdoor time", "outside time", and "outdoor AND measurement of time spent outdoors" were considered for this review. In total, three kinds of outdoor time measurements were discussed. Questionnaires have the longest history and are the most thoroughly revised instruments for assessing time spent outdoors, but recall bias is their most substantial drawback. Global positioning system (GPS) tracking can distinguish between indoor and outdoor locations, but its utility is limited due to several factors such as subject compatibility. Light exposure measurement devices are newly emerging, but all of these devices require good subject cooperation. Further efforts and exploration are needed to develop better methods and new tools to record exposure to the outdoors in real time. Moreover, inventing a new device by combining two or more types of devices mentioned above and using the latest technology of en ergy supplementation and autoswitching may make the best use of the advantages and bypass the disadvantages of each tool.

Refractive surgery: the most cost-saving technique in refractive errors correction

AIM

To compare the lifetime and annual economic burden of spectacles, contact lenses, and refractive surgery in correction of refractive errors.

METHODS

This is a cross-sectional study with convenience sampling which 120 patients were interviewed in a tertiary referral hospital in the Iranian health care system. The bottom-up based cost of illness approach was estimated using a face-to-face interview to assess the direct and indirect cost of different refractive errors correction of any correction technologies.

RESULTS

Correction with spectacle imposes a total direct cost of US dollar (US$) 342.5 (±8.41) per year and US$9373.5 (±230.1) per lifetime to each patient. These figures for the contact lenses were obtained US$198.3 (±0.12) and US$5203.1 (±256.3) and for refractive surgery were obtained US$19.1 (±1.2) and US$568.1 (±64.6), respectively. Overall, based on age-adjusted prevalence rates, astigmatism had the highest share of refractive errors economic burden with a lifetime direct cost of slightly less than US$5.49 billion, while hyperopia and myopia imposed less than US$5.24 and 4.2 billion on patients, respectively. The annually imposed cost on each individual Iranian patient with refractive errors is US$308.5.

CONCLUSION

Based on 18mo post refractive surgery course observation, which is generalized to whole life, refractive surgery significantly imposed much less cost compared with spectacles and contact lenses. Refractive errors among Iranians result in considerable economic burden. Using the refractive surgery instead of other two correction methods has the ability to reduce this economic loss in the future.

Cost and quality of life of overlooked eye care needs of children

Background

The objective of this research was to conduct a systematic review and cost analysis to summarize, from the Ministry of Health perspective, the costs families might incur because of their child’s prescription for refractive errors and amblyopia correction.

Methods

Databases including MEDLINE, Embase, BIOSIS, CINAHL, HEED, ISI Web of Science, and the Cochrane Library as well as the gray literature were searched. Systematic review was conducted using EPPI-Reviewer 4. Percentage difference in cost of glasses and patches per patient per various diagnoses were computed. The cost of glasses and patches was projected over a 5-year time horizon. Cost-utility analysis was performed.

Results

In total, 302 records were retrieved from multiple databases and an additional 48 records were identified through gray literature search. From these, a total of 14 studies (10,388 subjects) were eligible for quantitative analysis. The cost of glasses increased significantly for congenital cataract patients to US$1,820, esotropia patients to US$840, myopes to US$411, amblyopes (mixed) to US$916, anisometropes to US$521, and patients with strabismus to US$728 over a 5-year period making them unaffordable for low-income families. Incremental cost of glasses of congenital cataract patients with delayed treatment was computed to be US$1,690 per health utility gained. Incremental cost of glasses for high refractive error was US$93 per health utility gained in non-compliant children. For amblyopia patients, incremental cost of glasses per quality-adjusted life years gained was US$3,638.

Conclusion

Cost of corrective lenses is associated with significant financial burden and thus other means of mitigating costs should be considered. Eyesight problems in children are perceived as low-priority health needs. Thus, educational interventions on substantial visual deficits of not wearing glasses should be offered to families and governmental health agencies.

Isotope-coded protein label based quantitative proteomic analysis reveals significant up-regulation of apolipoprotein A1 and ovotransferrin in the myopic chick vitreous

This study used isotope-coded protein label (ICPL) quantitative proteomics and bioinformatics analysis to examine changes in vitreous protein content and associated pathways during lens-induced eye growth. First, the vitreous protein profile of normal 7-day old chicks was characterized by nano-liquid chromatography electrospray ionization tandem mass spectrometry. A total of 341 unique proteins were identified. Next, myopia and hyperopia were induced in the same chick by attaching -10D lenses to the right eye and +10D lenses to the left eye, for 3 and 7 days. Protein expression in lens-induced ametropic eyes was analyzed using the ICPL approach coupled to LCMS. Four proteins (cystatin, apolipoprotein A1, ovotransferrin, and purpurin) were significantly up-regulated in the vitreous after 3 days of wearing -10D lenses relative to +10D lens contralateral eyes. The differences in protein expression were less pronounced after 7 days when the eyes approached full compensation. In a different group of chicks, western blot confirmed the up-regulation of apolipoprotein A1 and ovotransferrin in the myopic vitreous relative to both contralateral lens-free eyes and hyperopic eyes in separate animals wearing +10D lenses. Bioinformatics analysis suggested oxidative stress and lipid metabolism as pathways involved in compensated ocular elongation.

[Secondary diseases in high myopia]

BACKGROUND

Eyes with high myopia (axial length ≥ 26.5 mm) do not just have a different size. Due to morphological and structural changes there is a considerably increased risk for many different secondary diseases.

OBJECTIVE

Determination of the incidence and mortality in high myopia, discussion of effects and clinical signs, presentation of treatment recommendations and counselling.

MATERIAL AND METHODS

A systematic search of the literature was carried out and a discussion on basic principles and epidemiological investigations is presented.

RESULTS

Findings due to high myopia are not in a closed state but undergo continuous changes. Choroidal neovascularization (adjusted prevalence 2.5-5%), staphyloma, foveoschisis and peripheral retinal degeneration are examples of problems contributing to the increased rate of visual impairment and blindness related to myopia. High myopia is associated with a clearly increased risk of retinal detachment after lens surgery (hazard ratio 6.1) and particularly more frequently in younger people. The associated primary open-angle glaucoma (odds ratio 2.46) is often recognized too late due to relatively low values of intraocular pressure.

CONCLUSION

Understanding of atrophic areas and staphyloma has benefited from recent advances in imaging (e.g. magnetic resonance imaging, optical coherence tomography and wide-field imaging) that complement and explain histological findings. Knowledge of the associated risk profile is of major clinical relevance.

Relationship between higher-order wavefront aberrations and natural progression of myopia in schoolchildren

This study investigated the relationship between higher-order aberrations (HOAs) and myopia progression as well as axial elongation in schoolchildren. We examined cycloplegic refraction, axial length, and wavefront aberrations prospectively in 71 myopic children. Changes in cycloplegic refraction and axial length during a 2-year study period were assessed, and their correlations with HOA components were analyzed. Sixty-four subjects ([mean ± SD] 9.2 ± 1.6 years) completed the 2-year examinations. Cycloplegic refraction was significantly changed after 2 years (P < 0.0001), and the average change (myopia progression) was -1.60 ± 1.04 D. Axial length also increased significantly (P < 0.0001), and the average increase (axial elongation) was 0.77 ± 0.40 mm. Myopia progression and axial elongation showed significant correlations with many components of corneal HOA (P < 0.0001 to P = 0.0270). Multivariate analysis showed that the total HOA of the cornea was the most relevant variable to myopia progression and axial elongation (P < 0.0001). Eyes with larger amounts of corneal HOAs showed less myopia progression and smaller axial elongation, suggesting that corneal HOAs play a role in the refractive and ocular developments in children.

Development of the FitSight Fitness Tracker to Increase Time Outdoors to Prevent Myopia

Purpose

To develop a fitness tracker (FitSight) to encourage children to increase time spent outdoors. To evaluate the wear pattern for this tracker and outdoor time pattern by estimating light illumination levels among children.

Methods

The development of the FitSight fitness tracker involved the designing of two components: (1) the smartwatch with custom-made FitSight watch application (app) to log the instant light illuminance levels the wearer is exposed to, and (2) a companion smartphone app that synchronizes the time outdoors recorded by the smartwatch to smartphone via Bluetooth communication. Smartwatch wear patterns and tracker-recorded daily light illuminance levels data were gathered over 7 days from 23 Singapore children (mean ± standard deviation age: 9.2 ± 1.4 years). Feedback about the tracker was obtained from 14 parents using a three-level rating scale: very poor/poor/good.

Results

Of the 14 parents, 93% rated the complete “FitSight fitness tracker” as good and 64% rated its wearability as good. While 61% of 23 children wore the watch on all study days (i.e., 0 nonwear days), 26% had 1 nonwear day, and 4.5% children each had 3, 4, and 5 nonwear days, respectively. On average, children spent approximately 1 hour in light levels greater than 1000 lux on weekdays and 1.3 hours on weekends (60 ± 46 vs. 79 ± 53 minutes, P = 0.19). Mean number of outdoor “spurts” (light illuminance levels >1000 lux) per day was 8 ± 3 spurts with spurt duration of 34 ± 32 minutes.

Conclusion

The FitSight tracker with its novel features may motivate children to increase time outdoors and play an important role in supplementing community outdoor programs to prevent myopia.

Translational Relevance

If the developed noninvasive, wearable, smartwatch-based fitness tracker, FitSight, promotes daytime outdoor activity among children, it will be beneficial in addressing the epidemic of myopia.

Epidemiology of Pathologic Myopia in Asia and Worldwide

The myopia epidemic in Asia is evident because the prevalence of high myopia among young adults is higher among Asian (6.8%-21.6%) compared with non-Asian populations (2.0%-2.3%). High myopia is linked to pathologic myopia (PM), which may cause irreversible visual impairment (VI). This review will highlight updates on the prevalence of PM and the associated VI from PM. The prevalence of PM among the middle-aged and elderly (0.9%-3.1%) is higher than the prevalence among children and adolescents (<0.2%). The PM lesions detected among older adults include advanced lesions, such as posterior staphyloma, chorioretinal atrophy, lacquer cracks, and Fuchs spot (in descending frequency of occurrence). A relatively high prevalence of PM (8%) was recently reported among highly myopic young adults. As young individuals grow older, the early grades of PM lesions are likely to progress to advanced grades. Two longitudinal changes that occur frequently in PM include the enlargement of beta peripapillary atrophy and the development of chorioretinal atrophy. The lack of longitudinal changes in PM limits the causal inferences of PM. The prevalence of VI attributed to PM seems to be higher among Asian populations compared with Western and European populations. Pathologic myopia is ranked as a more important cause of blindness and low vision in Asian populations compared with Western and European populations. With the lack of effective treatment strategies and poor prognosis, PM threatens the vision health of populations in Asia and worldwide. To control this future epidemic, the prevention of myopia onset and progression is necessary.