A systematic review of near work and myopia: measurement, relationships, mechanisms and clinical corollaries

Slowing of Greater Axial Length Elongation Stemming from the Coronavirus Disease 2019 Pandemic with Increasing Time Outdoors: The Tokyo Myopia Study

Purpose

To investigate the changes in axial length (AL) elongation and other ocular parameters before and during the coronavirus disease 2019 pandemic.

Design

A longitudinal school-based study.

Participants

Public elementary schoolchildren in Tokyo (grades 1-6; age, 6-12 years) participated in this study from 2018 to 2021.

Methods

All participants underwent eye examinations and provided written consent to measurements of the noncycloplegic refraction and ocular biometry including AL, among others. The students' parents also completed a questionnaire about the students' lifestyles. We included the right eye in our analysis and compared the changes in the ocular parameters among the periods using a linear mixed-effects model for repeated measures and examined the univariate and step-wise multiple regression analyses to evaluate the associations between myopia and other covariates.

Main Outcome Measures

Changes in AL elongation and other ocular parameters from 2018 to 2019 (prepandemic), that of 2019 to 2020 (immediately after the pandemic onset), and that of 2020 to 2021 (during the pandemic).

Results

A total of 578 students before the pandemic period, 432 immediately after the pandemic onset, and 457 during the pandemic period were evaluated. The changes in the ALs and spherical equivalents (SEs) a year before, immediately after onset, and during the pandemic were 0.31 mm/-0.20 diopter, 0.38 mm/-0.27 diopter, and 0.28 mm/-0.47 diopter, respectively (ALs, P < 0.001; SEs, P = 0.014). The results of the questionnaire showed that time spent outdoors daily had changed during the 3 years to 79, 63, and 77 minutes/day, respectively (P < 0.001). Time spent using smartphones or tablets increased year by year to 41, 52, and 62 minutes/day (P < 0.001). The greatest AL elongation occurred during the period when the shortest amount of time was spent outdoors during the 3 years.

Conclusions

These results suggested that the school closures and decreasing time spent outdoors might have caused greater AL elongation among schoolchildren in Tokyo; however, it is possible that, although the time spent in near work still increased, the return to the time spent outdoors to the prepandemic levels may have affected the slowing of AL elongation after lockdown.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Sunlight: Time for a Rethink?

UVR is a skin carcinogen, yet no studies link sun exposure to increased all-cause mortality. Epidemiological studies from the United Kingdom and Sweden link sun exposure with reduced all-cause, cardiovascular, and cancer mortality. Vitamin D synthesis is dependent on UVB exposure. Individuals with higher serum levels of vitamin D are healthier in many ways, yet multiple trials of oral vitamin D supplementation show little benefit. Growing evidence shows that sunlight has health benefits through vitamin D-independent pathways, such as photomobilization of nitric oxide from cutaneous stores with reduction in cardiovascular morbidity. Sunlight has important systemic health benefit as well as risks.

Ocular morbidity profiles of out-of-school children in a North Indian urban slum

PURPOSE

This study evaluates the recent trends in ocular morbidities and vision-related practices in "out-of-school" children in urban slums of Gurugram in North India.

METHODS

In this observational study, a validated questionnaire was administered to 161 students from two nonformal slum schools. Sociocultural, demographic data, vision-related practices, and visual acuity with subjective refraction of the children were recorded.

RESULTS

A total of 80 boys and 81 girls (9.17 ± 2.58 years) participated in this study. About 40% of the children were from lower socioeconomic status. The visual acuity recorded for all the children, except three children, was 6/6 in both eyes. One child had a pre-phthisical eye with no light perception, following a childhood trauma, with the other eye having 6/6 vision. Two children had refractive errors (myopia and compound myopic astigmatism), with a best corrected visual acuity (BCVA) of 6/6. Thirteen children (8%) had Bitot's spots and 67 (35.4%) had allergic conjunctivitis. Eight (5%) children complained of dry eye-related symptoms like redness and watering of eyes, while 19 (11.8%) had diffuse headache. Average number of years spent in school for these children was less than 1.7 years (range: 1 month-6 years). Only 10.5% of the children gave the history of watching television more than 30 h/week. Significant association was found between the income of father and use of digital devices in children below 10 years ( P = 0.003) and children playing outdoors ( P = 0.001). There was a significant association noted for age and use of digital devices ( P = 0.037).

CONCLUSION

The prevalence of refractive errors in "out-of-school" children of urban slum was much less than the national average. Almost one in three children suffered from eye allergies, while 8% children had Bitot's spots. The data about the prevalence of ocular comorbidities in underserved areas like urban slums can be used to update and strategize eye health-care delivery models for out-of-school children.

Mechanisms of emmetropization and what might go wrong in myopia

Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, the myopic retina has reduced ability to inhibit eye growth when positive defocus is imposed. (3) The bi-directional response of the emmetropic retina is elicited with low spatial frequency information below 8 cyc/deg, which makes it unlikely that optical higher-order aberrations play a role. (4) The retinal mechanism for the detection of the sign of defocus involves a comparison of defocus blur in the blue (S-cone) and red end of the spectrum (L + M-cones) but, again, the myopic retina is not responsive, at least not in short-term experiments. This suggests that it cannot fully trigger the inhibitory arm of the emmetropization feedback loop. As a result, with an open feedback loop, myopia development becomes "open-loop".

Development of the University of Houston near work, environment, activity, and refraction (UH NEAR) survey for myopia

CLINICAL RELEVANCE

There is a need to better elucidate demographic and behavioural factors that are contributing to the rising prevalence of myopia. Doing so will aid in developing evidence-based recommendations for behavioural modifications to prevent onset and slow progression of myopia in children.

BACKGROUND

The contributions of environmental and behavioural factors in myopia remain unclear. The goal of this work was to provide a standardised survey to better understand risk factors for myopia.

METHODS

Development of the survey was carried out in 4 phases. In phase 1, three methods (direct, lay terms, and indirect) of parental reporting for the presence of myopia in their child were investigated through a questionnaire (N = 109) to determine sensitivity and specificity. The best method determined from phase 1 was used in phase 2, where questions regarding demographics, ocular history, and visual behaviour were compiled and refined. In phase 3, the survey was administered to focus groups of parents (N = 9). In phase 4, a scoring system was developed.

RESULTS

The highest sensitivity for parental reporting for myopia of their child was the indirect method (0.84), and the lowest sensitivity was the direct method (0.41). The highest specificity was the direct method (0.86), once excluding the 'do not know' responses, and the lowest specificity was the indirect method (0.53). The direct method yielded a 53.2% 'do not know' response rate, 50.5% for the lay method, and 1.8% for the indirect method. Time to complete the survey was 10:09 ± 2:45 minutes.

CONCLUSION

This study provides a comprehensive and up-to-date myopia risk factor survey that can be utilised by researchers and clinicians. Parents found the survey to be easy to understand and relatively quick to answer, and the scoring system allows quantification of behaviours across different categories using provided equations.

Myopia Prevalence in Latin American Children and Adolescents: A Systematic Review and Meta-Analysis

Although myopia is a growing global concern, comprehensive studies on its prevalence among Latin American (LATAM) children and adolescents are still lacking. Thus, we conducted a systematic review and meta-analysis to determine the prevalence of myopia in LATAM children and adolescents aged three to 20. The study conducted a thorough literature search from January 1, 1975, to February 28, 2023, identifying 24 studies on the prevalence of myopia in LATAM that met the inclusion criteria. Quality assessment and standardized data collection were performed. The meta-analysis used a random-effects model due to heterogeneity and calculated prevalence rates. Finally, the analysis of data from 24 eligible studies revealed a myopia prevalence of 8.61% (range 0.80-47.36%, 95% confidence interval (CI): 5.22-13.87%, p < 0.05) among 165,721 LATAM children and adolescents. No significant age-based associations or temporal trends were observed in this study. Studies with non-cycloplegic or objective assessment exhibited a numerically higher, although statistically non-significant, myopia prevalence (10.62%, 95% CI: 4.9-21.6%) compared to studies using cycloplegia (7.17%, 95% CI: 3.40-14.50%). In conclusion, myopia affects approximately one in 11 LATAM children and adolescents. Given the increasing exposure of LATAM youth to known myopia risk factors, such as extensive near-work, online learning, and limited outdoor activities, it is crucial to monitor myopia trends in this region. Further research is imperative to address and prevent myopia in LATAM.

Myopia Control: Are We Ready for an Evidence Based Approach?

INTRODUCTION

Myopia and its vision-threatening complications present a significant public health problem. This review aims to provide an updated overview of the multitude of known and emerging interventions to control myopia, including their potential effect, safety, and costs.

METHODS

A systematic literature search of three databases was conducted. Interventions were grouped into four categories: environmental/behavioral (outdoor time, near work), pharmacological (e.g., atropine), optical interventions (spectacles and contact lenses), and novel approaches such as red-light (RLRL) therapies. Review articles and original articles on randomized controlled trials (RCT) were selected.

RESULTS

From the initial 3224 retrieved records, 18 reviews and 41 original articles reporting results from RCTs were included. While there is more evidence supporting the efficacy of low-dose atropine and certain myopia-controlling contact lenses in slowing myopia progression, the evidence about the efficacy of the newer interventions, such as spectacle lenses (e.g., defocus incorporated multiple segments and highly aspheric lenslets) is more limited. Behavioral interventions, i.e., increased outdoor time, seem effective for preventing the onset of myopia if implemented successfully in schools and homes. While environmental interventions and spectacles are regarded as generally safe, pharmacological interventions, contact lenses, and RLRL may be associated with adverse effects. All interventions, except for behavioral change, are tied to moderate to high expenditures.

CONCLUSION

Our review suggests that myopia control interventions are recommended and prescribed on the basis of accessibility and clinical practice patterns, which vary widely around the world. Clinical trials indicate short- to medium-term efficacy in reducing myopia progression for various interventions, but none have demonstrated long-term effectiveness in preventing high myopia and potential complications in adulthood. There is an unmet need for a unified consensus for strategies that balance risk and effectiveness for these methods for personalized myopia management.

Associations of meeting 24-hour movement behavior guidelines with prescribed eyeglasses/contact lenses among children and adolescents

BACKGROUND

Vision health is crucial for many aspects of life especially in developing populations such as children and adolescents. However, there is a high proportion of children and adolescents who suffer from visual impairments. Notably, accumulating evidence indicates that meeting the 24-hour movement behaviors (24-HMB) guidelines is associated with positive physical and mental health outcomes in children and adolescents. However, the relationship between being prescribed eyeglasses/contact lenses and meeting the 24-HMB guidelines has yet to be investigated. Thus, this study aimed to address this gap in the existing literature by using the 2021 National Survey of Children's Health (NSCH) dataset.

METHODS

In this cross-sectional study, data was retrieved from the 2021 NSCH. A total of 14,193 U.S. children and adolescents aged between 6 and 17 years were included for data analyses. We used items of the NSCH concerning the 24-HMB guidelines (i.e., physical activity, screen time, and sleep duration) and prescription of eyeglasses/contact lenses that were answered by the legal guardian of the children. Binary logistic regression was performed to investigate whether meeting the 24-HMB guidelines is associated with prescription eyeglasses/contact lenses and whether wearing eyeglasses/contact lenses predicts adherence to the 24-HMB guidelines among children and adolescents.

RESULTS

More than half of the participants (59.53%) wore eyeglasses/contact lenses and only 8.40% of them met all three of the 24-HMB guidelines. Compared to meeting none of the 24-HMB guidelines, meeting one (OR = 0.76, 95% CI = 0.62-0.93, p = 0.008), two (OR = 0.54, 95% CI = 0.43-0.67, p < 0.001), and all three 24-HMB guidelines (OR = 0.47, 95% CI = 0.34-0.64, p < 0.001) were associated with a lower risk of being prescribed eyeglasses/contact lenses among children and adolescents.

CONCLUSIONS

The findings of the current study provided evidence that the prevalence of U.S. children and adolescents aged between 6 and 17 years who wore eyeglasses/contact lenses was relatively high. Furthermore, meeting the 24-HMB guidelines was associated with a lower risk of being prescribed eyeglasses/contact lenses. Future studies focusing on the effects of 24-HMB interventions on vision health among children and adolescents are needed to better inform public health actions.

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.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia

PURPOSE

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye.

METHODS

The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length.

RESULTS

This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly.

CONCLUSION

The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

Analysis of factors related to the development of ocular biometric parameters in Chinese children aged 6-10 years: a cross-sectional study

OBJECTIVES

Emmetropia depends on the precise coordination of ocular biometry, including axial length (AL), corneal curvature, lens thickness and anterior chamber depth (ACD). Disruption of this coordination leads to refractive errors such as myopia. This article aimed to determine the factors affecting ocular biometry and myopia development in young children.

DESIGN

A cross-sectional study.

SETTING

This study was conducted in a primary school in the Yanqing district of Beijing, China.

PARTICIPANTS

792 students in grades 1-3 without hyperopia (>+2.00 D), strabismus, or amblyopia were selected.

EXCLUSIONS

students had conditions affecting best corrected visual acuity and whose guardians refused to provide informed consent. Ocular biometric measurements and non-cycloplegia autorefraction were performed. The questionnaire addressed factors such as perinatal factors and environmental factors.

INTERVENTIONS

None.

PRIMARY AND SECONDARY OUTCOMES

Ocular biometry and myopia.

RESULTS

According to the multivariate logistic regression analysis, electronic screen use >2 hours/day (OR=2.175, p=0.013), paternal myopia (OR=1.761, p=0.002), maternal myopia (OR=1.718, p=0.005), taller height (OR=1.071, p<0.001), maternal education (OR=0.631, p=0.012) and maternal gestational hypertension (OR=0.330, p=0.042) were associated with myopia. AL was affected by female sex (OR=0.295, p<0.001), older age (OR=1.272, p=0.002) and taller height (OR=1.045, p<0.001). Female sex (OR=0.509, p<0.001), taller height (OR=1.046, p<0.001), use of electronic screens >2 hours each day (OR=3.596, p<0.001) and time spent outdoors >2 hours each day (OR=0.431, p=0.001) influenced ACD incidence. Central corneal thickness (CCT) was associated with older age (OR=1.113, p=0.008), paternal education (OR=1.474, p=0.007), premature birth (OR=0.494, p=0.031), history of blue light therapy in infancy (OR=0.636, p=0.041) and history of incubator therapy in infancy (OR=0.263, p=0.009). Only sex influenced corneal curvature.

CONCLUSIONS

The factors associated with myopia were partly related to ACD and AL, and perinatal factors were associated with myopia and CCT.

TRIAL REGISTRATION NUMBER

ChiCTR2200065398.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

PROSPERO TRIAL REGISTRATION NUMBER

CRD42022333053.

Refractive and corneal astigmatism in Chinese 4-15 years old children: prevalence and risk factors

BACKGROUND

To investigate the prevalence and risk factors of refractive astigmatism (RA) and corneal astigmatism (CA) in preschool children and school-aged children in Shanghai, China.

METHODS

In this school-based, cross-sectional study, 4-15 years old children across three learning stages of kindergarten, primary school, and junior high school underwent noncycloplegic autorefraction and completed comprehensive questionnaires involving time spent on daily homework and outdoor activities. Data from the right eyes were analysed.

RESULTS

Overall, 7084 children (mean ± standard deviation (SD) of age: 8.08 ± 3.11 years) were included, and the prevalence rates of RA/CA ( ≤ - 1.0 D) in children were 15.8%/64% in kindergartens, 16.5%/65% in primary schools, and 32.8%/76.9% in junior high schools. The magnitude and prevalence of RA and CA all increased with age or with learning stage (all P < 0.001). The presence of RA was associated with more myopic spherical power (odds ratio (OR) 0.956, P = 0.021), junior high school (OR 1.973, P < 0.001), longer homework time on weekdays (OR 1.074, P = 0.029), and shorter outdoor activity time on weekends (odds ratio 0.929, P = 0.013).

CONCLUSION

In the wide age range of 4 to 15 years, the magnitude and prevalence of RA and CA increased with the learning stage, and these increases mainly began at the primary school stage. Factors, including longer homework time and shorter outdoor time were correlated with the presence of RA.

Attitudes and knowledge of myopia management by Spanish optometrists

PURPOSE

To investigate the knowledge, training and clinical practice of Spanish optometrists about preventing and controlling myopia progression.

METHODS

A web-based questionnaire was distributed to Spanish optometrists through social networks, optometric professional bodies and one of the major Spanish optometrists' associations to assess practitioner perception, understanding, and self-reported clinical practice behavior related to myopia diagnosis and management.

RESULTS

A total of 534 optometrists with a mean age of 40.8 ± 10.3 years completed the survey. Most respondents have been practicing optometry for more than 20 years (89.8%), report having actively treated childhood myopia (82.4%), and are very concerned about the increasing frequency of pediatric myopia in their daily practice (85.3%). Almost all of the respondents (97.3%) agreed that the efficacy of treatment is related to the age at which it is prescribed, and more than half (53.6%) considered a progression higher than - 0.50 and up to - 1.00D as the minimum necessary to consider a myopia management option. Respondents who reported actively managing childhood myopia considered orthokeratology, atropine and soft-defocus contact lenses the most effective myopia control interventions. However, the most frequently prescribed form of myopia correction by Spanish optometrists was single-vision spectacles, followed by orthokeratology and soft-defocus contact lenses.

CONCLUSIONS

Spanish optometrists are very active in the management of myopia, especially by fitting orthokeratology lenses or dual-focus soft contact lenses for myopia control, but there is still potential for improvement in the methodology they follow for both the diagnosis and management of myopia.

Advances in myopia prevention strategies for school-aged children: a comprehensive review

Myopia has significantly risen in East and Southeast Asia, and the pathological outcomes of this condition, such as myopic maculopathy and optic neuropathy linked to high myopia, have emerged as leading causes of irreversible vision loss. Addressing this issue requires strategies to reduce myopia prevalence and prevent progression to high myopia. Encouraging outdoor activities for schoolchildren and reducing near-work and screen time can effectively prevent myopia development, offering a safe intervention that promotes healthier habits. Several clinical approaches can be employed to decelerate myopia progression, such as administering low-dose atropine eye drops (0.05%), utilizing orthokeratology lenses, implementing soft contact lenses equipped with myopia control features, and incorporating spectacle lenses with aspherical lenslets. When choosing an appropriate strategy, factors such as age, ethnicity, and the rate of myopia progression should be considered. However, some treatments may encounter obstacles such as adverse side effects, high costs, complex procedures, or limited effectiveness. Presently, low-dose atropine (0.05%), soft contact lenses with myopia control features, and orthokeratology lenses appear as promising options for managing myopia. The measures mentioned above are not necessarily mutually exclusive, and researchers are increasingly exploring their combined effects. By advocating for a personalized approach based on individual risk factors and the unique needs of each child, this review aims to contribute to the development of targeted and effective myopia prevention strategies, thereby minimizing the impact of myopia and its related complications among school-aged children in affected regions.

Optical Biometry Changes Throughout Childhood and Adolescence in Patients Wearing Ortho-K Lenses

Background

Orthokeratology has been shown to suppress progressive myopia in some children. We examine the changes in optical biometry parameters in orthokeratology (Ortho-K) patients, in a retrospective longitudinal study at a tertiary eye care center in Ann Arbor, MI, USA.

Methods

Optical biometry measurements obtained with the Lenstar LS 900 (Haag-Streit USA Inc, EyeSuite software version i9.1.0.0) were aggregated from 170 patients who had undergone Ortho-K for myopia correction between 5 and 20 years of age. Pre-intervention biometry measurements were compared with follow-up measurements done 6-18 months after initiation of Ortho-K. Linear mixed models were used to quantify associations in biometry changes with age of intervention allowing for correlation between measurements on two eyes of the same patient.

Results

A total of 91 patients were included in the study. Axial length increased through the age of 15.7 ± 0.84 years for Ortho-K patients at our center. The growth curve in our Ortho-K population was comparable to previously published normal growth curves in Wuhan and Germany populations. Corneal thickness and keratometry decreased at a stable rate regardless of age of intervention (-7.9 µm, 95% CI [-10.2, -5.7], p < 0.001).

Conclusion

In our population, Ortho-K did not appear to affect the overall trajectory of axial length progression when compared to normal growth curves, despite showing a previously described reduction in corneal thickness. As Ortho-K has been shown to have varying effects that differ from individual to individual, it continues to be important to reassess its effects on new populations to better understand its ideal uses.

Myopia in elementary school students in Eastern China during the COVID-19 pandemic

Background

Myopia is an increasingly serious public concern, particularly among primary school students. The prevalence of myopia and its influencing factors in primary school pupils in Eastern China during the COVID-19 pandemic had not been explored.

Methods

A randomly clustered sampling method was performed, and selected pupils from grade 1 to grade 3 in 15 primary schools in the Fenghua District of Zhejiang Province were included and given myopia screening and uniform questionnaire survey 1 year later.

Results

A total of 4,213 students completed the myopia screening and questionnaire survey. Myopia was diagnosed in 1,356 pupils, with a myopia incidence of 32.19%. The spherical equivalent (SE) refraction of the included pupils decreased on average by 0.50 ± 2.15 D 1 year later. The myopia rate was positively correlated with the increase of grade, in which the myopia rate among grade 3 students was the highest at 39.69%. The myopia rate among female students was higher than that among male students. Students residing in urban areas had a higher myopia rate than in rural areas. Maintaining an near work distance ≥33 cm was a significant protective factor (OR = 0.84, 95% CI: 0.74-0.96). Students with two myopic parents had a higher risk of myopia (OR = 1.61, 95% CI: 1.34-1.92).

Conclusion

During the COVID-19 pandemic, the myopia rate among early primary school students in Eastern China was high. More attention and implementation of interventions from health and education departments, such as training the development of good eye behavior, should be considered to strengthen the intervention of myopia in primary school students.

Baseline characteristics in the Israel refraction, environment, and devices (iREAD) study

The purpose of this study is to present baseline data from a longitudinal study assessing behavioral factors in three groups of boys in Israel with varying myopia prevalence. Ultra-Orthodox (N = 57), religious (N = 67), and secular (N = 44) Jewish boys (age 8.6 ± 1.4 years) underwent cycloplegic autorefraction and axial-length measurement. Time-outdoors and physical-activity were assessed objectively using an Actiwatch. Ocular history, educational factors, and near-work were assessed with a questionnaire. Group effects were tested and mixed effects logistic and linear regression were used to evaluate behaviors and their relationship to myopia. The prevalence of myopia (≤ - 0.50D) varied by group (ultra-Orthodox: 46%, religious: 25%, secular: 20%, P < 0.021). Refraction was more myopic in the ultra-Orthodox group (P = 0.001). Ultra-Orthodox boys learned to read at a younger age (P < 0.001), spent more hours in school (P < 0.001), spent less time using electronic devices (P < 0.001), and on weekdays, spent less time outdoors (P = 0.02). Increased hours in school (OR 1.70) and near-work (OR 1.22), increased the odds of myopia. Being ultra-Orthodox (P < 0.05) and increased near-work (P = 0.007) were associated with a more negative refraction. Several factors were associated with the prevalence and degree of myopia in young boys in Israel, including being ultra-Orthodox, learning to read at a younger age, and spending more hours in school.

Myopia risk behaviour related to the COVID-19 lockdown in Europe: The generation R study

PURPOSE

To battle the spreading of the COVID-19 virus, nationwide lockdowns were implemented during 2020 and 2021. Reports from China revealed that their strict home confinements led to an increase in myopia incidence. The Netherlands implemented a more lenient lockdown, which allowed children to go outside. We evaluated the association between COVID-19 restrictions, myopia risk behaviour and myopia progression in Dutch teenagers.

METHOD

A total of 1101 participants (mean age 16.3 ± 3.65 yrs) completed questionnaires about their activities before, during and after lockdown (March-October 2020). We used a repeated-measures ANOVA to compare time use between these time periods. Ocular measurements were acquired before the COVID-19 pandemic when participants were 13 years old; only 242 participants had ocular measurements at 18 years of age at the time of this analysis. Linear regression analyses were used to evaluate the association between lifestyle factors and myopia progression.

RESULTS

Children were on average 16.2 (1.03) years of age during lockdown. Total nearwork increased from 8.11 h/day to 11.79 h/day, and remained higher after lockdown at 9.46 h/day (p < 0.001). Non-educational nearwork increased by 2.22 h/day (+49%) during lockdown and was associated with faster axial length progression (B 0.002 mm/h/year; SE 0.001 p = 0.03). Before and during lockdown, the mean time spent outdoors was similar (1.78 h/day and 1.80 h/day, respectively). After lockdown, time spent outdoors decreased to 1.56 h/day (p < 0.001).

CONCLUSION

The Dutch lockdown significantly increased digitised nearwork in adolescents but did not affect outdoor exposure. The changes in time spent performing nearwork remained after the lockdown measures had ended. We expect that the COVID-19 pandemic may lead to an increase in myopia prevalence and progression in European children.

Near work, light levels and dioptric profile - Which factor dominates and influences the short-term changes in axial length?

PURPOSE

Given the agonistic nature of near work to promote axial elongation and the antagonistic nature of time outdoors to prevent myopia, we aimed to investigate the following: (a) how the short-term effect of near work performed outdoors (Experiment 1) influences axial length and (b) how near work performed in two different dioptric profiles (uncluttered and cluttered) alters the changes in central axial length (Experiment 2).

METHODS

Forty-six adults (age range: 19-32 years) participated in the study. In Experiment 1, 22 participants completed a 15-min distance task and a reading task in both the outdoor (~30,000 lux) and indoor (~70 lux) locations. In Experiment 2, 24 participants performed the same reading task at a study desk in uncluttered and cluttered reading environments. Pre- and post-task ocular biometry measurements were performed for each session using a non-contact biometer.

RESULTS

In Experiment 1, a significant increase in axial length from baseline was found after performing reading tasks in both outdoor (mean ± SEM: +12.3 ± 3.4 μm, p = 0.001) and indoor locations (+11.9 ± 3.1 μm, p = 0.001). In Experiment 2, axial length increased significantly from baseline to post reading task, in both uncluttered (+17.9 ± 3.5 μm, p < 0.001) and cluttered reading environments (+19.2 ± 2.9 μm, p < 0.001). No significant changes in axial length were observed either between outdoor and indoor locations (p = 0.92) or between the uncluttered and cluttered reading environment (p = 0.75).

CONCLUSION

Independent of light intensity (outdoor or indoor location) and dioptric profile of the near-work environment (uncluttered or cluttered), a 15-min reading task led to a significant increase in axial length. While the long-term effects of these findings need to be evaluated, practitioners should emphasise how near work can reduce the beneficial effects of time outdoors, while providing recommendations related to time outdoors for myopia control.

[Recommendations for Progressive Myopia in Childhood and Adolescence. Statement of the DOG, BVA and the Bielschowsky Society for Strabismus Research and Neuroophthalmology - Status June 2022]

Since the last and at the same time first statement of the German ophthalmological societies on the possibilities of reducing myopia progression in childhood and adolescence, many new details and aspects have emerged in clinical research. This second statement updates the previous document and specifies the recommendations on visual and reading behavior as well as on pharmacological and optical therapy options, which have been both refined and newly developed in the meantime.

[Recommendations for progressive myopia in childhood and adolescence. Statement of the DOG, BVA and the Bielschowsky Society for Strabismus Research and Neuroophthalmology : Status June 2022]

Since the last and at the same time first statement of the German ophthalmological societies on the possibilities of reducing myopia progression in childhood and adolescence, many new details and aspects have emerged in clinical research. This second statement updates the previous document and specifies the recommendations on visual and reading behavior as well as on pharmacological and optical therapy options, which have been both refined and newly developed in the meantime.

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

SIGNIFICANCE

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

Myopia: why the retina stops inhibiting eye growth

In myopia, the eye grows too long, and the image projected on the retina is poorly focused when subjects look at a distance. While the retina normally controls eye growth by visual processing, it seems to give up during myopia development. But what has changed? To determine whether the sharp image is in front or behind the retinal plane, a comparison of image sharpness in red and blue would provide a reliable cue because focal planes are about 1.3 D apart due to longitudinal chromatic aberration (LCA). However, up to now, it could not be demonstrated that the retina does, in fact, such a comparison. We used a new approach: movies were digitally filtered in real time to present either the blue channel of the RGB color format unfiltered while green and red were blurred ("blue in focus"), or the red channel was unfiltered while green and blue were blurred ("red in focus") accordingly to the human LCA function. Here we show that, even though filtered movies looked similar, eyes became significantly shorter when the movie was sharp in the red plane but became longer when it was presented sharp in the blue plane. Strikingly, the eyes of young subjects who were already myopic did not respond at all-showing that their retina could no longer decode the sign of defocus based on LCA. Our findings resolve a long-standing question as to how the human retina detects the sign of defocus. It also suggests a new non-invasive strategy to inhibit early myopia development: keeping the red image plane on a computer screen sharp but low pass filtering the blue.

Short-Term Exposure to Violet Light Emitted from Eyeglass Frames in Myopic Children: A Randomized Pilot Clinical Trial

Violet light (VL), 360−400 nm wavelength, is contained in the sunlight and is an effective element for myopia suppression. This study is to investigate the safety and efficacy of novel eyeglasses that emit VL from the frames. This is a double-masked, randomized, pilot clinical trial conducted in a clinic in Japan. Forty-three children with myopia were enrolled. Participants were randomly assigned to two groups, wearing VL-emitting eyeglass frames (VLf) that emitted VL of 310 μW/cm2 (VLf group, n = 22) or pseudo-placebo eyeglass frames with a minimal emission of VL (<10 μW/cm2) (control group, n = 21). The exposure time was 3 h per day. The primary outcomes were visual acuity, tear film break-up time, corneal endothelial cell density, and the slit-lamp/fundus examinations. The secondary outcome was the 6-month changes in the axial lengths and cycloplegic refractions. Forty-one (95%) participants were included; twenty-one in the VLf group and twenty in the control group. No significant differences were seen in any safety evaluation. Significant changes were seen in axial elongation, choroidal thickness, and cycloplegic refractions in the subgroup analysis of 8- to 10-year-old children (p < 0.05), but otherwise no significant differences were seen. The VLf showed short-term safety and effectiveness against myopia progression.

Associations between reading and writing postures and myopia among school students in Ningbo, China

Background

We conducted this study to investigate the prevalence of myopia among school students in Ningbo and to explore the associations between reading and writing postures and myopia.

Methods

A population-based and cross-sectional study was conducted, and 3,256 school students aged 8-19 years were recruited. Each enrolled subject was assessed for uncorrected distance visual acuity (UDVA) using a standard logarithmic visual acuity E-chart and a non-cycloplegic autorefraction examination. Self-administered questionnaires were used to investigate myopia-related reading and writing postures and behavioral habits among school students.

Results

The prevalence of myopia among primary school, middle school, and high school students was 61.49, 81.43, and 89.72%, respectively. Regarding the associations between reading and writing postures and myopia, we identified that a reading distance >33 cm is a protective factor for myopia in female students [odds ratio (OR) = 0.31, 95% confidence interval (CI) = 0.15-0.64], in both primary school (OR = 0.55, 95% CI = 0.30-0.99) and middle school (OR = 0.37, 95% CI = 0.15-0.90).

Conclusions

A reading distance >33 cm can be used as an additional measure to prevent and control myopia. Proper postural measures for reading and writing may have educational and public health benefits.

Outbreak of COVID-19-Related Myopia Progression in Adults: A Preliminary Study

PURPOSE

The COVID-19 pandemic has necessitated specific public health measures, resulting in the alteration of lifestyles, such as increased digital screen time and fewer outdoor activities. Such conditions have increased the progression of myopia in children. However, no investigation of myopia progression in early adulthood has been conducted during this period. Consequently, this study aimed to evaluate the outbreak of COVID-19-related myopia progression among adults at an optometry clinic during the COVID-19 pandemic.

MATERIALS AND METHODS

This was a retrospective cohort study in which participants aged 18-25 years who first visited (baseline) the optometry clinic between June 2019 and March 2020 were recruited for follow-up from November 2021 to March 2022. Spherical equivalent refraction (SER), uncorrected distance visual acuity (UCDVA), and binocular cross cylinder (BCC) were recorded at baseline and a follow-up visit. Using questionnaires, a survey was conducted to assess the lifestyle changes that transpired during the COVID-19 pandemic.

RESULTS

In total, 37 participants with a mean age of 22.5±1.4 years were enrolled, of which 89.2% were female. Following the outbreak of the COVID-19 pandemic, most participants self-reported increased daily use of digital devices (89.2%), online education (86.5%), and spending more time at home (94.6%), which increased by approximately 7.6±3.2 hours, 5.9±1.7 hours, and 13.2±7.5 hours, respectively. There were statistically significant differences between SER and BCC at baseline and after approximately 2 years of the COVID-19 pandemic (p < 0.05). The mean two-year myopia progression was -0.59±0.67 D (Maximum = 0.00 D, Minimum = -3.38 D).

CONCLUSION

This study revealed that myopia could progress during adulthood among those who have lived under public health measures intended to address the COVID-19 pandemic.

Systematic review and meta-analysis of myopia prevalence in African school children

Purpose

Increased prevalence of myopia is a major public health challenge worldwide, including in Africa. While previous studies have shown an increasing prevalence in Africa, there is no collective review of evidence on the magnitude of myopia in African school children. Hence, this study reviews the evidence and provides a meta-analysis of the prevalence of myopia in African school children.

Methods

This review was conducted using the 2020 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Five computerized bibliographic databases, PUBMED, Scopus, Web of Science, ProQuest, and Africa Index Medicus were searched for published studies on the prevalence of myopia in Africa from 1 January 2000 to 18 August 2021. Studies were assessed for methodological quality. Data were gathered by gender, age and refraction technique and standardized to the definition of myopia as refractive error ≥ 0.50 diopter. A meta-analysis was conducted to estimate the prevalence. Significant heterogeneity was detected among the various studies (I² >50%), hence a random effect model was used, and sensitivity analysis was performed to examine the effects of outliers.

Results

We included data from 24 quality assessed studies, covering 36,395 African children. The overall crude prevalence of myopia over the last two decades is 4.7% (95% CI, 3.9–5.7) in African children. Although the prevalence of myopia was slightly higher in females (5.3%, 95%CI: 4.1, 6.5) than in males (3.7%, 95% CI, 2.6–4.7; p = 0.297) and higher in older [12–18 years 5.1% (95% CI, 3.8–6.3) than younger children (aged 5–11 years, 3.4%, 95% CI, 2.5–4.4; p = 0.091), the differences were not significant. There was a significantly lower prevalence of myopia with cycloplegic compared with non-cycloplegic refraction [4.2%, 95%CI: 3.3, 5.1 versus 6.4%, 95%CI: 4.4, 8.4; p = 0.046].

Conclusions

Our results showed that myopia affects about one in twenty African schoolchildren, and it is overestimated in non-cycloplegic refraction. Clinical interventions to reduce the prevalence of myopia in the region should target females, and school children who are aged 12–18 years.

Recent understanding of binocular vision in the natural environment with clinical implications

Technological advances in recent decades have allowed us to measure both the information available to the visual system in the natural environment and the rich array of behaviors that the visual system supports. This review highlights the tasks undertaken by the binocular visual system in particular and how, for much of human activity, these tasks differ from those considered when an observer fixates a static target on the midline. The everyday motor and perceptual challenges involved in generating a stable, useful binocular percept of the environment are discussed, together with how these challenges are but minimally addressed by much of current clinical interpretation of binocular function. The implications for new technology, such as virtual reality, are also highlighted in terms of clinical and basic research application.