Protective effects of increased outdoor time against myopia: a review

Topical Dopamine Application on Form-Deprivation Myopia in Rabbits

Background/Objectives: This study aimed to investigate the efficacy of topical dopamine administration in inhibiting form deprivation (FD) myopia in a rabbit model. Methods: A total of 16 neonatal New Zealand white rabbits were randomly assigned to two groups: a control group and a dopamine treatment group. FD myopia was induced in both groups by applying a light diffuser to one eye. The dopamine group received daily topical instillations of 4% dopamine in the eye with FD myopia, while the control group received normal saline instillations over a four-week period. Axial length measurements were taken to assess the degree of myopia, and histological analysis was performed to evaluate retinal safety and structural integrity. Results: The results indicated that dopamine treatment significantly inhibited axial elongation of the FD eyes compared to the control group, with measurements of 15.07 ± 0.34 mm for the dopamine group versus 15.63 ± 0.33 mm for the control group (p = 0.015). Histological analysis showed no evidence of structural alterations or apoptosis in the retina, confirming the safety of topical dopamine. Conclusions: Topical dopamine appears to be a promising therapeutic approach for controlling the progression of myopia in a rabbit model, demonstrating significant efficacy in reducing axial elongation without inducing ocular toxicity. These findings highlight the potential of dopamine in managing myopia and warrant further investigation in clinical settings.

Myopia in Children: Epidemiology, Genetics, and Emerging Therapies for Treatment and Prevention

Refractive errors, particularly myopia, are among the most prevalent visual impairments globally, with rising incidence in children and adolescents. This review explores the epidemiology and risk factors associated with the development of refractive errors, focusing on the environmental and lifestyle factors contributing to the current surge in myopia. We provide an overview of key genetic factors and molecular pathways driving the pathogenesis of myopia and other refractive errors, emphasizing the complex interplay between genetic predisposition and environmental triggers. Understanding the underlying mechanisms is crucial for identifying new strategies for intervention. We discuss current approaches to slow myopia progression in pediatric populations, including pharmacological treatment regimens (low-dose atropine), optical interventions, and lifestyle modifications. In addition to established therapies, we highlight emerging innovations, including new pharmacological agents and advanced optical devices, and insights into potential future treatments. Cutting-edge research into gene therapy, molecular inhibitors, and neuroprotective strategies may yield novel therapeutic targets that address the root causes of refractive errors. This comprehensive review underscores the importance of early intervention and highlights promising avenues for future research, aiming to provide pediatricians with guidance to ultimately improve clinical outcomes in managing and preventing myopia progression in children and young adults.

Media Device Use and Vision Disorders in the Pediatric Age: The State of the Art

INTRODUCTION

Evidence is consistent with increased screen viewing time among children and adolescents, and anticipation at the age at which children interact with media devices. Incorrect use of technology, as well as overuse, may lead to serious consequences. This study aims to revise scientific international literature and to describe the potential eye risks correlated to screen viewing time in the pediatric age.

MATERIALS AND METHODS

A review of the literature was performed according to the PRISMA 2020 guidelines, using the search terms "media device" and "eye" with the filter "age 0-18".

RESULTS

Analyzing the international literature, we found 26 articles. Pre-myopia, myopia, digital eye strain, and acute acquired comitant esotropia were listed as potential and time-related consequences associated with the incorrect use of media devices among children and adolescents.

DISCUSSION

Family education on media device exposure and potential risk for children and adolescents' sight in case of prolonged digital/screen exposure is required. During pediatric check controls, a dialogue with families on prolonged media device use at a close distance should be undertaken. Pediatricians and ophthalmologists should consider screen viewing time in case of ocular problems.

Blue light stimulation of the blind spot in human: from melanopsin to clinically relevant biomarkers of myopia

The protective effects of time spent outdoors emphasize the major role of daylight in myopia. Based on the pathophysiology of myopia, the impact of blue light stimulation on the signaling cascade, from melanopsin at the blind spot to clinically relevant biomarkers for myopia, was investigated. Parameters and site of light stimulation are mainly defined by the photopigment melanopsin, that is sensitive to blue light with a peak wavelength of 480 nm and localized on the intrinsically photosensitive retinal ganglion cells (ipRGC) whose axons converge to the optic disc, corresponding to the physiological blind spot. Blue light at the blind spot (BluSpot) stimulation provides the opportunity to activate the vast majority of ipRGC and avoids additional involvement of rods and cones which may exert incalculable effects on the signaling cascade.Experimental studies have applied anatomical, histochemical, electrophysiological, imaging, and psychophysical methods to unravel the mode of action of BluSpot stimulation. Results indicate activation of melanopsin, improvement of contrast sensitivity, gain in electrical retinal activity, and increase of choroidal thickness following BluSpot stimulation. Short-term changes of clinically relevant biomarkers lead to the hypothesis that BluSpot stimulation may exert antimyopic effects with long-term application.

Effects of wearing myopia glasses on eye movement and scleral blood supply

The present study examined the effect of wearing myopia glasses on eye movement and scleral blood supply. For this purpose, a total of 30 individuals were recruited for the present self-control study. Under the same fixation distance, the individuals wore 0.00 D and -10.00 D glasses. The amount of eye movement generated when shifting from gazing at a central point to a point light source located at the left or right was measured and compared between the two glasses. The results revealed that the range of eye movement was significantly reduced after wearing -10.00 D glasses. When gazing at the right point light source from the central point, the difference between the rotation distances of the right eye when wearing the 0.00 D glasses and the -10.0 D glasses was 0.73±0.45 mm (t=8.93, P<0.01) and that of the left eye was 0.73±0.43 mm (t=9.34, P<0.01). Similar results were obtained when the left point light source was viewed from a shift in gaze from the central point. On the whole, the present study demonstrates that wearing concave lenses limits eyeball movement. Restricted eyeball movement can affect vascular changes within the extraocular muscles and blood flow, thereby affecting the blood supply to the anterior segment and sclera of the eye, potentially accelerating the development of myopia.

Association between weekend catch-up outdoor duration and prevalence of myopia: evidence from a cross-sectional, multi-center study in China

BACKGROUND

This study aimed at investigating the relationship between the weekend catch-up outdoor duration (WCOD) and prevalence of myopia among students in China.

METHODS

This cross-sectional study recruited participants in 107 schools (six cities, 30 districts) from China from May to June 2021. Demographic characteristics (age, grade, sex, ethnicity, BMI, resident, and parents' myopia), optically habits (bad writing habits, working/studying time per day, continuous working/studying time per day, and screen time per day) and outdoor duration (weekday and weekend) were obtained from questionnaire. WCOD was defined as outdoor time 1 h longer on weekends than on weekdays. Spherical equivalent (SE) of refractive error were measured with non-cycloplegic refraction. Adjusted multivariate logistic regression analysis was performed to evaluate the relationship between WCOD and prevalence of myopia.

RESULTS

Students with myopia had shorter WCOD compared with those without myopia (P < 0.001). Adjusted multivariate logistic regression analyses showed negative associations between WCOD and prevalence of myopia in Chinese students, especially in students with WCOD of 2-3 h (OR = 0.577, P < 0.001) and 3-4 h (OR = 0.571, P = 0.004) when the weekday outdoor duration was 0.5-1 h, as well as students with WCOD of 2-3 h (OR = 0.614, P = 0.003) when the weekday outdoor duration was 1-2 h. Similar results were observed in students with high myopia. Students with high myopia had shorter WCOD compared with those without high myopia (P = 0.001). Negative associations between WCOD and prevalence of high myopia were significant in students with WCOD of 1-2 h when the weekday outdoor duration was < 0.5 h (OR = 0.585, P = 0.007) and 0.5-1 h (OR = 0.537, P = 0.018).

CONCLUSION

Our study, for the first time, reported that a WCOD have a potential to reduce the prevalence of myopia and high myopia in Chinese students.

Effect of virtual reality-based visual training for myopia control in children: a randomized controlled trial

BACKGROUND

To assess the efficacy and safety of virtual reality-based visual training (VRVT) in myopia control among children.

METHODS

The randomized, parallel-group, single-blind clinical trial conducted at the Department of Ophthalmology of Shanghai Tenth People's Hospital enrolled 65 low-myopic children (aged 8 to 13 years) with cycloplegic spherical equivalent (SE) between - 0.50 and - 3.00 diopters (D), astigmatism less than - 1.00 D, anisometropia less than 1.50D, and best corrected visual acuity (BCVA) more than 0.0 logarithm (LogMAR) of the minimum angle of resolution. The participants were enrolled in December 2020, and the follow-up of this study concluded on August 2021. Children were assigned randomly to the intervention group (VRVT plus single-vision spectacle [SVS]) and the control group (only SVS without receiving VRVT). The intervention group was administered for 20 min per day with VRVT under parental supervision at home. The primary outcome was changes in axial length (AL) at 3 months. Macular choroidal thickness (mCT) was regarded as a key secondary outcome.

RESULTS

Among 65 participants (mean age: 10.8 years, 52.3% male), 60 children (92.3%) who completed the 3-month intervention and 6-month follow-up were included in the analysis (30 in the intervention group and 30 in the control group). The changes of AL were 0.063 ± 0.060 mm (95% confidence interval [CI], 0.074 to 0.119 mm) in the intervention group and 0.129 ± 0.060 mm (95% CI, 0.107 to 0.152 mm) and in the control group at 3 months (t = - 2.135, P = 0.037), and the mean difference between the two groups was 0.066 mm. The change of mCT were 22.633 ± 36.171 μm (95% CI, 9.127 to 36.140 μm) in the intervention group and - 3.000 ± 31.056 μm (95% CI, - 14.597 to 8.597 μm) in the control group at 3 months (t = 2.945, P = 0.005). VR vertigo was the most common adverse event which was occurred in two children (2/30, 6.67%) in the intervention group.

CONCLUSIONS

VRVT is a promising method for myopia control in children with good user acceptability. Among children aged 8 to 13 years with low-myopia, nightly use of VRVT resulted in slowing myopia progression.

TRIAL REGISTRATION

This protocol was registered with ClinicalTrials.gov (NCT06250920), retrospectively registered on 01 February 2024.

Regional disparities in the prevalence and correlated factors of myopia in children and adolescents in Gansu, China

Background

Myopia is a significant public health problem across the globe. This study aimed to examine the regional disparity in prevalence and correlated factors of myopia in children and adolescents in two typical regions, Gannan Tibetan Autonomous Prefecture (Gannan Prefecture for short, a Tibetan residential area) and Wuwei City (a Han residential area) in Gansu Province, China, and to provide a reference for the prevention and control of regional myopia.

Methods

The study was a cross-sectional study of children and adolescents in Gansu Province, China. A total of 6,187 (Wuwei City: 3,266, Gannan Tibetan Autonomous Prefecture: 2,921) students were selected by stratified cluster sampling. Eye examinations and questionnaires were administered to the participants. Myopia is defined as a condition in which the spherical equivalent refractive error of an eye is less than or equal to -0.50 D when ocular accommodation is relaxed. The χ2 test and multivariate logistic regression analysis were used to analyze the correlated factors of myopia.

Results

The myopia rate of 6,187 students was 71.4%, and students had a higher rate of myopia (77.5%) in Wuwei City compared to Gannan Prefecture (64.6%) (p < 0.001). The results of multivariate analysis in Wuwei City showed that girls (odds ratio (OR) = 1.325), junior students (OR = 2.542), senior students(OR = 4.605), distance between eyes and book less than one foot (OR = 1.291), and parents with myopia (one, OR = 2.437; two, OR = 4.453) had higher risks of myopia (all, p < 0.05). For Gannan Prefecture, girls (OR = 1.477), senior students (OR = 1.537), daily time spent doing homework ≥2 h (OR = 1.420), the distance between eyes and book less than one foot (OR = 1.205), mean time continuous eye use (0.25-<0.5 h, OR = 1.345, 0.5-<1 h, OR = 1.317, ≥1 h, OR = 1.313), average daily sleep duration <8 h (OR = 1.399), and parents with myopia (one, OR = 1.852; two, OR = 2.913) had higher risks of myopia (all, p < 0.05).

Conclusion

The prevalence of myopia is at a relatively high level in Gansu Province. The prevalence and risk factors for myopia vary by region.

Bi-Gaussian analysis reveals distinct education-related alterations in spherical equivalent and axial length-results from the Gutenberg Health Study

PURPOSE

The aim of this study is to investigate the distribution of spherical equivalent and axial length in the general population and to analyze the influence of education on spherical equivalent with a focus on ocular biometric parameters.

METHODS

The Gutenberg Health Study is a population-based cohort study in Mainz, Germany. Participants underwent comprehensive ophthalmologic examinations as part of the 5-year follow-up examination in 2012-2017 including genotyping. The spherical equivalent and axial length distributions were modeled with gaussian mixture models. Regression analysis (on person-individual level) was performed to analyze associations between biometric parameters and educational factors. Mendelian randomization analysis explored the causal effect between spherical equivalent, axial length, and education. Additionally, effect mediation analysis examined the link between spherical equivalent and education.

RESULTS

A total of 8532 study participants were included (median age: 57 years, 49% female). The distribution of spherical equivalent and axial length follows a bi-Gaussian function, partially explained by the length of education (i.e., < 11 years education vs. 11-20 years). Mendelian randomization indicated an effect of education on refractive error using a genetic risk score of education as an instrument variable (- 0.35 diopters per SD increase in the instrument, 95% CI, - 0.64-0.05, p = 0.02) and an effect of education on axial length (0.63 mm per SD increase in the instrument, 95% CI, 0.22-1.04, p = 0.003). Spherical equivalent, axial length and anterior chamber depth were associated with length of education in regression analyses. Mediation analysis revealed that the association between spherical equivalent and education is mainly driven (70%) by alteration in axial length.

CONCLUSIONS

The distribution of axial length and spherical equivalent is represented by subgroups of the population (bi-Gaussian). This distribution can be partially explained by length of education. The impact of education on spherical equivalent is mainly driven by alteration in axial length.

Is Spending More Time Outdoors Able to Prevent and Control Myopia in Children and Adolescents? A Meta-Analysis

INTRODUCTION

Spending more time outdoors was treated as a safe and cost-effective method to prevent and control myopia. While prior research has established an inverse association between outdoor time and the risk of myopia onset, the effect of increasing outdoor time in delaying the progression of myopia remains a subject of debate. The present meta-analysis aimed to assess the relationship between outdoor time and the myopia onset, and further examine whether there is a dose-response relationship between outdoor time and the risk of myopia onset. Meanwhile, perform whether the outdoor time is related to delaying the progression of myopia.

METHODS

Studies were retrieved from PubMed, Web of Science, Embase, Medline, and the Cochrane Database, spanning from their inception to February 2023. Three cohort studies and 5 prospective intervention studies were included, with a total of 12,922 participants aged 6-16 years.

RESULTS

Comparing the highest with the lowest exposure levels of time spent outdoors, the highest outdoor time was strongly associated with a reduced risk of myopia onset (odds ratio [OR]: 0.53; 95% confidence interval [CI]: 0.34, 0.82). A nonlinear dose-response relationship was found between outdoor time and myopia onset risk. Compared to 3.5 h of outdoor time per week, an increase to 7, 16.3, and 27 h per week corresponded with a respective reduction in the risk of myopia onset by 20%, 53%, and 69%. Among children and adolescents who were not myopic, spending more time outdoors significantly slowed down the speed of change in spherical equivalent refractive (weighted mean difference [WMD] = 0.10D, 95% CI: 0.07, 0.14) and axial length (WMD = -0.05 mm, 95% CI: -0.06, -0.03). Among children and adolescents who were already myopic, spending more time outdoors did not slow myopia progression.

CONCLUSIONS

Overall, spending more time outdoors can prevent the onset of myopia, but it does not seem to slow its progression. Further studies are needed to better understand these trends.

Investigation and analysis of the status of myopia and related behavior in children and adolescents in Northeast Sichuan

PURPOSE

In this study, we examined the current status of myopia among primary and secondary school children in northeastern Sichuan to analyze the factors connected to myopia and provide data support and a theoretical foundation for the prevention and control of myopia.

METHODS

Using a cross-sectional study and a comprehensive sampling survey, 34,138 students aged 5-19 years were screened for refraction in 22 primary and secondary schools in Langzhong, and 4000 behavioral questionnaires were delivered at random. After evaluation and rational problem-solving, a total of 3764 valid questionnaires were obtained. SPSS 23.0 statistical software was used for data analysis.

RESULTS

The percentage of myopia among primary and secondary school students in Langzhong was 65.61%, with female students having a higher rate than male students ( P < 0.05); 52.81% of primary school students, 86.26% of secondary school students, and 88.17% of high school students had myopia. The incidence of myopia detection increased with school age ( P < 0.001), indicating a correlation between age and myopia prevalence. The prevalence of myopia was mainly low (40.53%) and moderate myopia (19.89%). The prevalence of high myopia (5.19%) was relatively high. The prevalence of myopia among female students (5.54%) was greater than that in male students ( P < 0.05) and increased with age ( P < 0.001). The proportion of students who wore eyeglasses was 24.36%, with a larger proportion of female students (25.93%) than male students (22.61%) ( P < 0.001). In addition, the rate of eyeglass use increased with school age ( P < 0.001). A logistic regression analysis revealed that higher grade point averages, female gender, and long-term usage of electronic items were risk factors for myopia. The results of the questionnaire survey revealed that students in this region were under immense pressure to perform well academically, spent a lot of time engaged in near-work activities, and had a low rate of myopia awareness; 24.43% of the students had not had a vision examination in the previous year, indicating that parents did not pay sufficient attention to eye health.

CONCLUSION

The incidence of myopia among children and teenagers is high in Northeast Sichuan, and the outlook for addressing the problem is bleak. Therefore, it is critical to improve vision monitoring and eye health education.

Vitamin D and myopia: a review

Myopia is a worldwide public health problem of vision disorder caused by multiple factors, which has posed a huge socioeconomic burden, raising concerns about sight-threatening ocular complications. Vitamin D, as a kind of fat-soluble vitamin, related to time-spent-outdoors, has been considered by extensive studies to have potential relationship with myopia. We reviewed studies published in a decade which estimated the association of blood vitamin D status with myopia and summarized the universality and individuality of all research articles. Several research articles suggested the known environmental risk factors of myopia, including age, gender, ethnicity, education level, parental and school conditions, time-spent-outdoors, and sunlight exposure, and recent epidemiological studies demonstrate that increased vitamin D levels, by virtue of the extended outdoor time, may be an important modifiable factor and a protective effect that delay the progression of myopia in children and adolescents rather than in adults. The genetic studies have been conducted to get access to the evidence of gene polymorphism for explaining the association of serum vitamin D status and myopia, but the precise genetic interpretation of vitamin D and myopia remains unclear so far; on the other hand, the possible mechanisms are various like copolymerization mechanism, calcium homeostasis and imbalance of ciliary muscle function regulation, but nearly all of the investigators are inclined to remain skeptical. This article reviews the age-related epidemiological proofs, existent genetics correlations, possible underlying biological mechanisms and further values for the protective association between vitamin D and myopia, providing the possibility of prevention or postponement for myopia.

Acupuncture modulates development of myopia by reducing NLRP3 inflammasome activation via the dopamine-D1R signaling pathway

BACKGROUND

Dopamine has been suggested to be a stop signal for eye growth and affects the development of myopia. Acupuncture is known to increase dopamine secretion and is widely used to treat myopia clinically.

OBJECTIVE

The aim of this study was to determine if acupuncture inhibits myopia progression in form deprived Syrian hamsters by inducing rises in dopamine content that in turn suppress inflammasome activation.

METHODS

Acupuncture was applied at LI4 and Taiyang every other day for 21 days. The levels of molecules associated with the dopamine signaling pathway, inflammatory signaling pathway and inflammasome activation were determined. A dopamine agonist (apomorphine) was used to evaluate if activation of the dopaminergic signaling pathway suppresses myopia progression by inhibiting inflammasome activation in primary retinal pigment epithelial (RPE) cells. A dopamine receptor 1 (D1R) inhibitor (SCH39166) was also administered to the hamsters.

RESULTS

Acupuncture inhibited myopia development by increasing dopamine levels and activating the D1R signaling pathway. Furthermore, we also demonstrated that nucleotide-binding oligomerization domain (NOD)-, leucine-rich repeat (LRR)- and pyrin domain-containing protein 3 (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome activation was inhibited by activation of the D1R signaling pathway.

CONCLUSION

Our findings suggest that acupuncture inhibits myopia development by suppressing inflammation, which is initiated by activation of the dopamine-D1R signaling pathway.

Repeated Low-Level Red Light Therapy for the Control of Myopia in Children: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Repeated low-level red light (RLRL) therapy has been suggested to be effective in children with myopia. However, evidence from randomized controlled trials (RCTs) is still limited. We performed a meta-analysis of RCTs to systematically evaluate the efficacy of RLRL on changes of axial length (AL) and cycloplegic spherical equivalent refraction (SER) in children with myopia.

METHODS

Relevant RCTs were obtained through a search of electronic databases including PubMed, Embase, Cochrane Library, Wanfang, and China National Knowledge Infrastructure from inception to September 15, 2022. A random-effects model was used to pool the results after incorporating the influence of potential heterogeneity. Subgroup analyses were performed according to the control treatment and follow-up duration.

RESULTS

A total of seven RCTs involving 1,031 children with myopia, aged 6 to 16 years, were included in the meta-analysis. Compared with control treatment without RLRL, treatment with RLRL was associated with a significantly reduced AL (mean difference [MD]: -0.25 mm, 95% confidence interval [CI]: -0.32 to -0.17, P <0.001; I 2 =13%) and a significantly increased cycloplegic SER (MD: 0.60 D, 95% CI: 0.44-0.76, P <0.001; I 2 =20%). Further subgroup analyses showed consistent results in studies comparing children wearing single vision lenses and those receiving active treatment including orthokeratology or low-dose atropine eye drops, as well as studies of treatment duration of 6 and 12 months.

CONCLUSIONS

Results of the meta-analysis suggested that RLRL treatment is effective for slowing down the progression of myopia in children aged 6 to 16 years.

Repeated Low-Level Red-Light Therapy for Controlling Onset and Progression of Myopia-a Review

Repeated low-level red-light (RLRL), characterized by increased energy supply and cellular metabolism, thus enhancing metabolic repair processes, has gained persistent worldwide attention in recent years as a new novel scientific approach for therapeutic application in myopia. This therapeutic revolution led by RLRL therapy is due to significant advances in bioenergetics and photobiology, for instance, enormous progresses in photobiomodulation regulated by cytochrome c oxidase, the primary photoreceptor of the light in the red to near infrared regions of the electromagnetic spectrum, as the primary mechanism of action in RLRL therapy. This oxidase is also a key mitochondrial enzyme for cellular bioenergetics, especially for the nerve cells in the retina and brain. In addition, dopamine (DA)-enhanced release of nitric oxide may also be involved in controlling myopia by activation of nitric oxide synthase, enhancing cGMP signaling. Recent evidence has also suggested that RLRL may inhibit myopia progression by inhibiting spherical equivalent refraction (SER) progression and axial elongation without adverse effects. In this review, we provide scientific evidence for RLRL therapy as a unique paradigm to control myopia and support the theory that targeting neuronal energy metabolism may constitute a major target for the neurotherapeutics of myopia, with emphasis on its molecular, cellular, and nervous tissue levels, and the potential benefits of RLRL therapy for myopia.

Prevalence and associated factors of myopia among school students in Shenyang, China: a cross-sectional study

Background

In recent years, the prevalence of myopia has increased significantly and caused great concern. Nevertheless, an estimate of myopia in the student population in Shenyang, Liaoning Province, China is still lacking. This study aims to determine the prevalence of myopia among students in Shenyang and investigate the associated factors affecting myopia development.

Methods

Standard logarithmic visual acuity chart and automatic computerized optometry under non-ciliary muscle paralysis were used to test the students' naked visual acuity of their right and left eyes. The included students were organized to fill in questionnaires on WeChat to collect the factors affecting myopia.

Results

A total of 34,644 students with a median age of 11.9 years were examined, including 17,563 males and 17,081 females. The overall prevalence of myopia was 60%, with a prevalence of 45% for mild myopia, 13% for moderate myopia, and 1.9% for high myopia. The sex, high educational stage, family history of myopia, doing homework after school or reading and writing for more than 2 h were associated with a higher risk of myopia, while doing eye exercises twice a day or more, going outdoors during recess, reading and writing with eyes more than one foot from books, and sleeping more than 8 h a day were associated factors for preventing myopia. The associated factors influencing myopia vary among different subgroups.

Conclusion

The prevalence of myopia in Shenyang is at a high level. In addition to sex, high educational stage and genetic factors, environmental factors including length of eye usage, eye exercises, outdoor activities, eye working distance, and sleep duration are associated with myopia prevalence. Therefore, it is recommended that the occurrence and development of myopia can be prevented by controlling the above environmental factors.

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.

Charting the landscape of the environmental exposome

The exposome depicts the total exposures in the lifetime of an organism. Human exposome comprises exposures from environmental and humanistic sources. Biological, chemical, and physical environmental exposures pose potential health threats, especially to susceptible populations. Although still in its nascent stage, we are beginning to recognize the vast and dynamic nature of the exposome. In this review, we systematically summarize the biological and chemical environmental exposomes in three broad environmental matrices-air, soil, and water; each contains several distinct subcategories, along with a brief introduction to the physical exposome. Disease-related environmental exposures are highlighted, and humans are also a major source of disease-related biological exposures. We further discuss the interactions between biological, chemical, and physical exposomes. Finally, we propose a list of outstanding challenges under the exposome research framework that need to be addressed to move the field forward. Taken together, we present a detailed landscape of environmental exposome to prime researchers to join this exciting new field.

Investigation on the prevalence and influencing factors of myopia among children and adolescents in Liyang city

OBJECTIVE

To investigate the prevalence of myopia among children and adolescents in a local area (Liyang City) of China and analyze the influencing factors, so as to formulate corresponding preventive measures.

METHODS

A questionnaire survey was conducted, mainly investigating subjects' age, gender, residence (urban/rural areas), parental myopia, daily time spent outdoors, daily sleep time, distance between computer screen and eyes, less than one punch (10 cm) from the chest to the edge of the desk when reading and writing, one inch (3 cm) between finger and pen tip when writing, number of in-school physical education (PE) classes, length of TV watching, and size of TV. The myopia of all participants was recorded.

RESULTS

This study enrolled 7,948 children and adolescents, including 4,733 (59.55%) cases of myopia, 1,025 (12.90%) of astigmatism, 251 (3.16%) of hyperopia, and 699 (8.79%) of anisometropia respectively. There were 2,519 (53.22%) cases of myopia in the left eye and 2,214 (46.78%) in the right eye. Low, moderate, and high myopia were determined in 2,682 (56.67%), 1,583 (33.45%), and 468 (9.89%), respectively. In terms of spherical equivalent (SEQ), a statistically lower SEQ was observed in urban areas (-1.56±0.46 d) versus suburban counties (-1.17±0.33 d), and in females (-1.68±0.30 d) compared with males (-1.17±0.44 d). The mean SEQ gradually decreased with age. The prevalence of myopia was 63.84% (2,436/3,816) in females, statistically higher than that of 55.59% (2,197/4,132) in males (χ²=56.00, P < 0.0001). The incidence of myopia was statistically higher in urban areas (67.93% [3,321/4,889]) versus rural areas (46.16% [1,412/3,059]). Parental myopia, one inch between finger and pen tip when writing, daily time spent outdoors, daily sleep time, distance between computer screen and eyes, less than one punch from the chest to the edge of the desk when reading and writing, number of in-school PE classes, and daily length of TV watching were significantly correlated with the occurrence of myopia.

CONCLUSIONS

Parents are advised to pay attention to daily time spent outdoors, sleep time, distance between the computer screen and the eyes, distance between the chest and the edge of the table when reading and writing, and length of TV watching of their children. As far as schools are concerned, PE activity time should be properly maintained to ensure that children have enough outdoor exercise time to reduce eye fatigue.

Effects of air pollution on myopia: an update on clinical evidence and biological mechanisms

Myopia is one of the most common forms of refractive eye disease and considered as a worldwide pandemic experienced by half of the global population by 2050. During the past several decades, myopia has become a leading cause of visual impairment, whereas several factors are believed to be associated with its occurrence and development. In terms of environmental factors, air pollution has gained more attention in recent years, as exposure to ambient air pollution seems to increase peripheral hyperopia defocus, affect the dopamine pathways, and cause retinal ischemia. In this review, we highlight epidemiological evidence and potential biological mechanisms that may link exposure to air pollutants to myopia. A thorough understanding of these mechanisms is a key for establishing and implementing targeting strategies. Regulatory efforts to control air pollution through effective policies and limit individual exposure to preventable risks are required in reducing this global public health burden.

Does Physical Activity Moderate the Relationship between Myopia and Functional Status in Children 9-11 Years of Age?

Although previous studies have reported an association between physical activity (PA) and myopia in school-aged children, little is known about the link between myopia and children’s functional status. The purpose of this study was to investigate dynamic balance control in relation to the daily PA levels of myopic schoolchildren aged 9−11 years (n = 52) versus a non-myopic control group (n = 53). A single leg stance test performed on the instability platform of the Biodex Balance System was used to assess balance control. The overall stability index (OSI), anterior-posterior stability index (APSI) and medial-lateral stability index (MLSI) were analyzed. PA levels were calculated using the World Health Organization European Childhood Obesity Surveillance Initiative family record form. Myopes and non-myopes were separated into three subgroups based on PA level (low, moderate and high). Myopia significantly affected OSI (F = 40.46, p < 0.001), APSI (F = 33.93, p < 0.001) and MLSI (F = 49.51, p < 0.001). There were significant differences (p < 0.001) between myopic and non-myopic children with low and moderate levels of PA, whilst there were no differences between compared children with high levels of PA. High PA levels had a positive impact on balance control in myopes. Our results showed that PA levels moderate the relationship between myopia and children’s functional status.

Association of Physical Activity and Sedentary Behaviors with the Risk of Refractive Error in Chinese Urban/Rural Boys and Girls

Background: Research shows physical activity (PA) is negatively associated with refractive error, especially outdoor activity. Our study aimed to examine the association of PA levels and sedentary time (SED) with refractive error in boys and girls living in urban and rural areas. Methods: A total of 8506 urban/rural boys and girls (13.5 ± 2.8 years old) in Shaanxi Province, China participated in this study. Questions about PA, SED, outdoor exercises, and digital screen time were asked in the study survey. Non-cycloplegic refractive error was measured by an autorefractor. The differences between sex/area groups have been analyzed by one-way ANOVA. The association of PA/SED with spherical equivalent (SE) and cylinder power was analyzed by general linear regression. The association between PA/SED and the risk of refractive error was determined using the binary logistic regression model. Results: Of the 8506 participants, the prevalence of refractive error was significantly higher in girls and urban students (p < 0.05). Less SED and digital screen time, and more outdoor activity were significantly associated with SE (p < 0.05), respectively. More PA and less SED were significantly associated with lower cylinder power (p < 0.05), respectively. More PA and less SED were significantly associated with lower risks of myopia and astigmatism, respectively (p < 0.05). Conclusions: PA and SED were associated with the risk of refractive error. Maintaining a healthy lifestyle can help to reduce the risk of refractive error in boys and girls.

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.

The change of myopic prevalence in children and adolescents before and after COVID-19 pandemic in Suqian, China

Purpose

The aim of this study was to investigate the change of myopic prevalence in students with different demographic characteristics before and after the COVID-19 pandemic in Suqian, China.

Methods

A retrospective, cross-sectional study was conducted. Student data from 52 schools in 2019 and 2020 were collected from the electronic medical records database through cluster sampling. Ophthalmic examinations were conducted on students from September to December in 2019 and 2020. Measurements of uncorrected visual acuity (UCVA) and noncycloplegic autorefraction were included to obtain the spherical equivalent refraction (SER) and prevalence of myopia. The difference in the rate of myopia and SER of students ages 6 to 18 with various demographic characteristics was compared between the two years.

Results

Records from 118,479 students in 2019 and the 121,881 students in 2020 were obtained. In 2019 and 2020, the prevalence of overall myopia increased from 43.1% to 48.9% (5.8 percentage point), and a substantial shift in myopic rate occurred in grades 4 to 6 (6.9 percentage point). The change in the prevalence of myopia in girls (5.9 percentage point) was approximately equal to that in boys (5.8 percentage point) and it was more common in rural students (5.9 percentage point) than in urban students (5.1 percentage point). The prevalence of low myopia increased more in children, and the prevalence of moderate myopia increased more in adolescents. The mean spherical equivalent refraction (SER) (-1.34±2.03 D) was lower in 2020 than in 2019 (-1.16±1.92 D), while SER decreased mainly at ages 7 to 15. The SER presented myopic status at the age of 9 (-0.55±1.26 D in 2019, -0.71±1.42 D in 2020), and attained moderate myopia at the age of 15 (-3.06±2.41 D in 2019, -3.22±2.40 D in 2020).

Conclusions

After the COVID-19 pandemic, myopia increased in this population with variable rates of increase in different demographic groups. The change of myopia in children was comparatively greater than that in adolescents. Therefore, we should take measures to prevent and control the development of myopia after the COVID-19 pandemic, especially for younger students.

Light Signaling and Myopia Development: A Review

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Puberty could regulate the effects of outdoor time on refractive development in Chinese children and adolescents

Aim

To explore the impact of puberty on refractive development and its interaction with outdoor time in children and adolescents.

Methods

In this 2-year observational study, students aged 7–13 years were selected with cluster sampling. All participants underwent cycloplegic refraction and axial length measurements once every year. Information of related factors was acquired through proper questionnaire or inquiry. The level of testosterone/estradiol was detected from the saliva of the subjects using the ELISA kit. Multiple linear regression and generalised estimating equation (GEE) were used to analyse the relationship among puberty, outdoor activities and refractive indicators.

Results

A total of 776 children and adolescents were included, with an average baseline age of 9.64±1.54 years and 53.6% boys. There were 350 myopes (55.2% of the 634 cyclopleged subjects) at baseline. There was a significant difference in the mean axial length changes and outdoor time among different puberty groups (for axial length: p=0.017, for outdoor time: p=0.015). Myopic parents, less outdoor time and more changes in estradiol were associated with greater changes in axial length and spherical equivalent (SE) (axial length changes: parental myopia β=0.230, outdoor time β=−0.250, changes in estradiol β=0.261; SE changes: parental myopia β=−0.267, outdoor time β=0.256, changes in estradiol β=−0.297). In the GEE model, the interaction between outdoor time and puberty was significantly associated with axial length (p=0.024, β=1.199).

Conclusions

This study implies puberty may play a regulating role on the relationship between outdoor time and refractive development among Chinese children and adolescents, which provides clues for in-depth mechanism interpretation and efficient intervention strategies.