Development Of Myopia In Children Research Articles

Prevention of Myopia Development in Children and Adolescents and Precautions

Myopia has increased epidemically in recent years and has become a global epidemic with significant public health implications. Identifying children at risk of developing myopia and implementing strategies to prevent or delay the onset of myopia can significantly reduce the burden of myopia on the individual and society. The strong causal role of education and time spent outdoors on myopia development suggests that lifestyle changes can be applied as preventive measures to children at risk, significantly impacting the myopia epidemic by preventing myopia onset and associated ocular pathologies.

LED light sources with a sun-like emission spectrum for children’s institutions

The article looks more like a scientific-theoretical than an experimental one, so it is proposed to remove the IMRAD structure, especially since it is given only in the summary, but not in the article itself.
 “In Russia, under the national project “Education”, a large-scale program for the construction of schools is underway. About 700 schools have already been built, and if in general for all programs, this is 900 schools..... Many schools have swimming pools, modern canteens...” noted the head of the relevant ministry at a meeting with the President of the Russian Federation Vladimir Putin at the beginning of 2023. In total, about 750 billion rubles were allocated to finance the program for the construction of new schools. (it includes 454 billion from the federal budget). In total, it is planned to build 1,300 educational institutions, which will have more than 1 million places. In addition to the construction of new schools, the plan provides for the implementation of a program of capital repairs and technical renovation of existing general education institutions by the end of 2026: it will include 7,300 buildings. The pace of capital renovations has also accelerated in 2022–2023: three thousand buildings will be renovated, mainly in rural areas. By 2024, all 27 thousand rural schools, according to modern requirements, will be equipped with modern equipment. In modern schools, it is planned to equip computer classes with modern computing equipment, and energy saving plans provide for the widespread use of LED lighting. The reasons for the negative effects of the light spectrum of LED lighting and personal computer monitors on the health 
 of children and adolescents, in particular the increase in myopia, have not yet been sufficiently studied.
 Analytical, sociological, and statistical methods were used.
 The relationship between physiological and behavioural factors that may lead to decreased vision is described. The restructuring of the work of the visual analyzer, associated with the selection of information in accordance with the models proposed in the social environment has been suggested to contribute to the formation 
 of myopia; with a decrease in one’s own search activity with increased myopia; with an increase in the functioning of internal information processing systems and 
 a decrease in the systems of perception and implementation of actions.
 Limitations. The study was limited to the area of study of the subject of research, materials from the Scopus, Web of Science, MedLine, The Cochrane Library, EMBASE, Global Health, CyberLeninka, RSCI databases and our own experiments.
 Conclusion. The spectral composition of artificial light and its intensity give rise to the prerequisites for the development of myopia or another functional-structural response in the variety of ganglion, amacrine cells, and receptors in the visual analyzer of multicellular animals. The narrow and incomplete spectrum of light from domestic LED lamps cannot be a good choice for the prevention of myopia in children. Considering the diversity of opsins in the human visual analyzer, we have developed and manufactured an artificial, light source using LEDs and phosphors, the spectrum of which considers the spectral photosensitivity of opsins in the human eye and is close as possible to the spectrum of sunlight at a correlated colour temperature of about 4000 and 3000 K. The first one has now been manufactured a batch of lamps, the spectral composition of the emitted light of which has no analogues and is ahead of the world’s best samples in terms of spectrum composition and efficiency level. The spectrum of this light source was demonstrated in a presentation at the Erisman Readings 2023. To elucidate the biological mechanisms of the development of myopia in children, additional efforts are needed within the framework of a new scientific direction - evolutionary hygiene. This will make it possible to establish how small changes in the composition of the light spectrum (emission in the region of 410–450 nm, dip in the region of 480 nm and absence of 380 nm) of artificial sources influenced catastrophic (chaotic) changes at the genetic level of humans and the entire living world.

Nutritional intake, environmental factors, and their impact on myopia prevalence in Korean children aged 5–12 years

BackgroundMyopia is a complex condition influenced by numerous factors, including genetic predisposition, environmental factors, and lifestyle choices. Although evidence indicates that certain dietary factors may influence the development of myopia, this relationship is still not completely understood and is a topic of ongoing research.MethodsThis study analyzed the relationship between dietary habits, environmental factors, and the prevalence of myopia in a sample of 24,345 children aged 5–12 years from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII). The average daily intake of dietary nutrients associated with the refractive error status of the participants was analyzed using analysis of variance (GLM) and the Scheffe method for post-hoc comparison. Multiple logistic regression analysis was conducted between the participant’s refractive error status and daily dietary nutrient intake, while taking into consideration the age, sex, BMI, parental myopia, and near-work hours.ResultsThe risk of myopia increased with age, especially notable between ages 11 and 12, and was higher in children with both parents having myopia. Dietary factors played a crucial role; children with myopia had significantly lower intake of fat, omega-3 fatty acids, and retinol but higher intake of other nutrients compared to emmetropic and hyperopic counterparts. High consumption of carbohydrates, protein, phosphorus, iron, potassium, and sodium was associated with increased myopia risk. High sodium intake was particularly associated with a 2.05-fold increased myopia risk.ConclusionsThis study highlights the significant role of diet and lifestyle choices in the development of myopia in children. Our findings suggest the importance of considering these specific factors in the management and prevention strategies for myopia, underscoring the need for targeted interventions in children's health and vision care.

Characteristics of Peripheral Retinal Refraction and Its Role in Children with Different Refractive States.

Peripheral retinal refraction plays a crucial role in myopia, but the specific mechanism is not clear. We refined the retinal partitions to explore the characteristics of peripheral retinal refraction and its role in emmetropic, low, and moderate myopic children aged 6 to 12 years. A total of 814 subjects (814 eyes) were enrolled in the study. The participants were divided into three groups according to the central spherical equivalent refraction (SER), which were emmetropia group (E), low myopia group (LM) and moderate myopia group (MM). Multispectral refractive topography (MRT) was used to measure the retinal absolute and relative refractive difference value (RDV) in different regions. The range was divided into superior, inferior, temporal, and nasal RDV (SRDV, IRDV, TRDV, and NRDV) on the basis of several concentric circles extending outward from the macular fovea (RDV15, RDV30, RDV45, RDV30-15, RDV45-30, and RDV-45). Kruskal-Wallis test was used to analyze the differences of peripheral refraction for all the regions among the three groups. Spearman rank correlation was performed to explore correlations between SER and RDV, axial length (AL) and RDV. The absolute value of RDV decreased with increasing degree of myopia in all regions (P < 0.01). Subjects with different refractive degrees had different relative value of RDV. In nasal position within 45° and temporal position within 30°, the peripheral retina exhibited significantly different relative hyperopic refractive status among Group E, Group LM, and Group MM (P < 0.05). SER was negatively correlated with NRDV within 30° (especially in the range of NRDV30-15) (r = -0.141, P < 0.01), positively correlated with TRDV within 15° (r = 0.080, P = 0.023), and not significantly correlated with SRDV and IRDV when the retina was divided into four parts. AL was positively correlated with NRDV within 30° (especially in the range of NRDV30-15) (r = 0.109, P = 0.002), negatively correlated with TRDV within 15° (r = -0.095, P = 0.007). The peripheral defocus has significant implications for the genesis of myopia. The peripheral defocus of the horizontal direction, especially within the range of NRDV30, has greater effect on the development of myopia in children. Higher NRDV30 is associated with lower SER and longer AL.

Expert consensus on stages of public health strategies for myopia prevention and control in children and adolescents

Myopia has emerged as a public health issue with the increasing prevalence of myopia in children and adolescents in China. In the clinical diagnosis and treatment of myopia, there are clinical stages and classifications, but they are not suitable for the prevention and control of myopia at the public health level. At the public health level, because there is no staging standard for myopia, there is a lack of staging prevention and control guidance for different refractive errors. Therefore, the Public Health Ophthalmology Branch of the Chinese Preventive Medicine Association organized domestic experts in relevant fields to conduct literature searches and discuss based on the research data on myopia at home and abroad, put forward the stages of public health strategies for myopia prevention and control and corresponding group prevention and control measures for each stage to reached this experts consensus. This consensus first proposes a method for assessing myopia risk, in order to predict the occurrence and development of myopia in children and adolescents; From the perspective of public health, myopia prevention and control is further divided into four stages: myopia prodromal stage, myopia development stage, high myopia stage, and pathological myopia stage. According to this consensus, myopia prevention and control technology is targeted and implemented in different stages to provide guidance for myopia prevention and control from the perspective of public health.

Effects of online family health education on myopia prevention in children by parental myopia: a randomized clinical trial

ABSTRACT Clinical relevance Online family health education may be effective for myopia prevention in children, and the effects may be different between children with myopic and non-myopic parents. Background Myopia is a common cause of vision loss. The aims of this study were to evaluate the effects of online family health education on preventing the development of myopia in children, and to estimate whether the effects vary according to parental myopia. Methods A cluster randomised trial including grade 1 and grade 2 children from 12 primary schools was conducted in Guangzhou, China. Weekly online family health education messages were sent to parents in the intervention group. Data collection included eye examinations of children and questionnaires completed by parents. Results Among the 3123 children included at baseline (1703 boys [54.5%]; mean [SD] age, 6.83 [0.73] years), 2376 completed the follow-up after 3 years. The differences in the incidence of myopia and myopic shift between the study groups were not significant in total. However, the 3-year cumulative incidence rate of myopia in the intervention group (125 of 445 [28.1%]) was significantly lower than that in the control group (225 of 603 [37.3%]; difference, 9.2% [95% CI, −14.9% to −3.5%]; P = 0.001) among children with non-myopic parents. In parallel, among children with non-myopic parents, the mean myopic change in SER was less for the intervention group than for the control group (−1.10 D vs. −1.24 D; difference, 0.13 D [95% CI, 0.03 to 0.23 D]; P = 0.01). Conclusions Compared with children with myopic parents, online family health education was more effective in children with non-myopic parents. The incidence of myopia and myopic shift in refraction have been reduced in children with non-myopic parents. Further studies are needed to assess these differences by parental myopia.

Relative Myopic Defocus in the Superior Retina as an Indicator of Myopia Development in Children.

To investigate the role of peripheral refraction in children's myopization. This 2-year study included 214 children (8-15 years old). Refraction across the retina (field of view: 60° × 36°) was measured with a custom-made aberrometer every year. Three datasets were established: dataset 1, 214 subjects from baseline to the first-year visit; dataset 2, 152 subjects from baseline to the second-year visit; and dataset 3, 59 initial emmetropes from baseline to the second-year visit. The baseline refraction of different retina regions was correlated with the central myopic shift, and was compared among groups with different levels of myopic shift. In datasets 1 and 2, the refraction distribution across the retina was significantly different among the subjects who were initially emmetropes but not among those who were initially hyperopic or myopic. Refraction in the central vertical retina, especially in the superior retina (r = -0.5, P < 0.001), was significantly correlated with the myopic shift for emmetropes in that subjects with more relative myopia in the superior retina manifested greater central myopic shifts. In dataset 3, 21 subjects remained emmetropic after 2 years, 15 subjects became myopic at the 1-year visit, and 23 subjects became myopic at the 2-year visit. No difference was found for the relative peripheral refraction in all of the peripheral regions between the stage prior to and after the onset of myopia. Relative myopic defocus in the superior retina could be a predictor of central myopia shift. Changes in relative peripheral refraction are more likely a consequence of myopia progression rather than a cause.

Effection of tear film stability on orthokeratology

Orthokeratology (Ortho-K) is one of the effective methods to control the development of myopia in children and adolescents. The mechanical pressure of eyelids on the Ortho-K lens and the hydraulic effect of tears under the Ortho-K lens can alter the curvature or shape of the cornea, which can correct refractive error and control myopia development progress. The tear film is a thin layer of liquids evenly distributing in the conjunctival sac. Wearing an Ortho-K lens can decrease the tear film stability, which will influence the Ortho-K. In this article, the relevant domestic and overseas research results are summarized and analyzed, aiming to sort out and discuss the effection of tear film stability on the fitting, shaping, safety, and visual quality of the Ortho-K, as well as to provide suggestions for clinicians and researchers.

Parallelism between hypovitaminosis D3 and recently detected myopia in children with amplified screen use in the COVID-19 era-A preliminary study.

This introductory study aims to analyze the association of serum vitamin D3 levels with recently detected myopia in Indian children following home confinement post-COVID-19 pandemic. Children aged 5-15 years who had not attended physical school in the past 1 year and visited the ophthalmology department with various ocular symptoms were divided into two groups: the myopic group with recently detected myopia and the non-myopic group with ocular ailments other than myopia. All children underwent basic ophthalmic evaluation and a general physical examination. Blood samples were collected for serum vitamin D3 levels. A pretested questionnaire inquiring about the duration of exposure to a digital screen, outdoor activities, and socioeconomic status was filled out for all children. The mean serum vitamin D3 level in the myopic group was 28.17 ± 15.02 ng/dl in comparison to 45.36 ± 17.56 ng/dl in the non-myopic group (P value < 0.05). Linear regression of the data establishes that myopia is associated with hypovitaminosis D3 (OR- 13.12, 95% CI 2.90-50.32, a P value of 0.001). The correlation between spherical equivalent and vitamin D3 levels was significant (Pearson correlation value: 0.661). In the myopic group, 63.3% of children had screen use >6 hours against 43.3% of children in the non-myopic group. In the myopic group, 33.3% of the children had an outdoor activity duration of <2 hours against 6.6% of children in the non-myopic group. This study proposes hypovitaminosis D3 as a strong factor associated with the development of myopia in children. Although it is a preliminary study, it suggests that the trial for vitamin D3 supplementation in young children to delay or cease the development of myopia is warranted.

A comparative analysis of myopia development in children with bilateral and unilateral pseudophakia

After the extraction of congenital cataract in infancy, postoperative refraction changes differently in patients with bilateral and unilateral pseudophakia. Purpose: to compare myopia development in children with bilateral and unilateral pseudophakia. Material and methods. We examined 33 children (63 eyes) with bilateral and 21 children with unilateral pseudophakia for long-term results of congenital cataract extraction performed in their infancy, The evaluated parameters included the incidence and degree of myopia, refraction, general postsurgical astigmatism, and axial length of the eye. Refraction was measured by Nidek ARK-530A (Japan). The axial length was measured by ultrasound B-scan (Voluson E8, GE) or by optical biometry (AL-Scan, Nidek). Results. In bilateral pseudophakia, high myopia was detected if astigmatism was more than 3.25 D or oblique. In the latter case, the eyeball showed a greater growth as compared to with-the-rule astigmatism (4.67 mm and 3.26 mm, respectively; p &lt; 0.05). With incomplete correction of astigmatism in the case of bilateral pseudophakia, myopia progressed to a high degree in nearly half of the cases (48.1 %), and a greater growth of the eye was detected compared with complete correction (4.45 mm and 3.42 mm respectively; p &gt; 0.05). The type and degree of astigmatism did not affect the development and progression of myopia in unilateral pseudophakia. Conclusion. The effect of undercorrected astigmatic defocus on the development and progression of myopia in bilateral pseudophakia is apparently associated with a equivalent visual load on both eyes, while this load is significantly reduced in unilateral pseudophakia so that it fails to affect the development of myopia in such cases.

Effects of mild- and moderate-intensity illumination on short-term axial length and choroidal thickness changes in young adults.

Previous studies have shown that time spent outdoors is protective against myopia development in children. In this study, we examined the effects of 500 and 1000lux of illumination to the eye on axial length (AL) and choroidal thickness (CT) changes in young adults. Fifteen participants (mean age, 21.60years [2.16]) with a mean refraction of -0.34 D (0.37) were exposed to 500 and 1000lux of illumination for 120min in a dark room on two different days, using a pair of light-emitting glasses. Ocular measurements were repeated on an additional day in darkness (~5lux). Ocular biometrics and CT were measured and analysed in the right eye before the light exposure (0min), after 30, 60 and 120min of exposure and 30min after light offset to measure recovery using the Lenstar biometer and the Cirrus optical coherence tomographer, respectively. Exposure to 500 and 1000lux of illumination resulted in a significant reduction in AL at 30, 60 and 120min compared to darkness (AL change at 120min: darkness, +0.020mm [0.004]; 500lux, -0.006mm [0.004]; 1000 lux, -0.013mm [0.004]; p<0.001). Exposure to 500 and 1000lux caused a significant overall thickening of the subfoveal choroid compared to darkness (CT change across 120min: darkness, -0.010mm [0.007]; 500lux, +0.006mm [0.005]; 1000lux, +0.009mm [0.003], p=0.02). Ocular changes were not significantly different between the two illumination levels (p>0.05) and returned to baseline within 30min of light offset. Exposure to mild- or moderate-intensity illumination on the eye can induce a significant short-term reduction in AL and an increase in CT in young adults. Future studies on larger cohorts with varying light intensities are needed to better understand the effects of ocular illumination on AL changes in humans.

Axial Elongation During Short-Term Accommodation in Myopic and Nonmyopic Children.

PurposeAxial length increases during accommodation in adults and children; however, refractive error group differences are conflicting and have not been explored in pediatric populations. This study aimed to evaluate differences in accommodation-induced axial elongation between myopic and nonmyopic children.MethodsA range of ocular biometric measurements were captured during brief accommodation tasks (0, 3, 6, and 9 D) using a Badal optometer mounted to a noncontact optical biometer (Zeiss IOLMaster 700). Reliable measurements were captured for 15 myopic and 15 age- and sex-matched nonmyopic children. The average central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), anterior segment length (ASL), vitreous chamber depth (VCD), and axial length (AL) were determined for each accommodation stimulus. Raw measurements of AL and VCD were corrected for the estimated error associated with LT increases during accommodation.ResultsAll biometric parameters, except CCT, changed significantly during accommodation (all P < 0.001). Myopic children exhibited significantly greater accommodation-induced axial elongation than nonmyopic children (P = 0.002) at the 3, 6, and 9 D accommodation stimuli, with a mean difference of 7, 10, and 16 µm, respectively (all pairwise comparisons, P ≤ 0.03). The changes in all other biometric parameters were not different between the refractive error groups (P ≥ 0.23).ConclusionsAccommodation-induced axial elongation was greater in myopic than nonmyopic children. This finding could support a potential mechanism linking near work, axial elongation, and myopia development in children or may reflect greater susceptibility to accommodation-induced axial elongation in children with established myopia.

Impact of COVID-19 Home Confinement in Children's Refractive Errors.

Background: Myopia is a public health problem, with estimations that 50% of the world population will be myopic by 2050. Some environmental factors, such as time spent outdoors, doing near work, and using digital devices, influence the development of myopia in children. Home confinement in Spain has increased these risk factors, so this study aims to investigate the impact of home confinement during the COVID-19 outbreak in the vision of school-aged children; Methods: A cross-sectional study in children between 5 and 7 years old that completed a visual screening and a questionnaire about their lifestyles at opticians in Spain in September and October of 2019 and 2020. Statistical analysis to compare lifestyles pre and post confinement, and vision in 2020 versus a similar cohort examined at the same opticians in 2019, was conducted; Results: Spanish children spent less time outdoors and more time doing near work in 2020 than in 2019 (p ≤ 0.001). There was a significant decrease of the spherical equivalent (mean ± standard deviation; 0.66 ± 2.03 D in 2019 vs. 0.48 ± 1.81 D in 2020; p ≤ 0.001); Conclusions: Lifestyles of Spanish children changed during the home confinement at the beginning of 2020. Together with changes in their lifestyles, spherical equivalents have decreased, which implies higher figures of myopia for children aged between 5 and 7.

Intensive online courses promote the development of myopia in children with orthokeratology lens during COVID-19 epidemic

AIM: To study the effect of intensive online courses on myopia in primary and middle school students with orthokeratology-lens during Corona Virus Disease 2019 (COVID-19) epidemic. METHODS: A total of 77 children in myopia with orthokeratology lens in outpatients from February to August 2020 were included in the study. Take a questionnaire to statistics times spending on online course, school class, playing digital electronic good, outdoor activity, homework, sleeping during the COVID-19 epidemic and school time, and analyze the differences of axial length(AL) variation between the COVID-19 epidemic and school time. RESULTS: For elementary school students, the time spending on online course and school class were 2.69±1.02h and 4.07±0.78h per day respectively (P<0.001), 6.67±1.82h and 6.31±1.19h per day were spent on short-distance use of eyes during the COVID-19 period and school time, respectively (P<0.001). For middle school students, the time spending on online course and school class were 4.35±1.59h and 6.33±0.66h per day respectively (P<0.001), 9.19±2.46h and 7.85±0.81h per day were spent on short-distance use of eyes (P=0.010) during the COVID-19 period and school time, respectively. For elementary school students, the average increase of right eye AL were 0.15±0.09mm and 0.06±0.06mm (P<0.001), the increase of left eye AL were 0.12±0.16mm and 0.07±0.09mm (P=0.048) during the COVID-19 period and school time, respectively. For middle school students, the average increase of right eye were AL 0.08±0.08mm and 0.05±0.05mm (P=0.242), and the average increase of left eye AL were 0.13±0.09mm and 0.04±0.06mm (P<0.001) during the COVID-19 period and school time, respectively. The results showed that both the time of short-distance use of digital electronic product and totally time on close visual study increased significantly during the epidemic period, the growth of AL was faster than that in school time, and the myopia increased rapidly. CONCLUSION: During the COVID-19 epidemic, intensive online lessons resulted in the time of short-distance use of digital electronic product increase significantly. Meanwhile, the AL growth accelerates significantly compared with that during school time and finally lead to myopia increased. Copyright 2021 by the IJO Press.

Effects of Single and Repeated Intravitreal Applications of Atropine on Choroidal Thickness in Alert Chickens

Introduction: Atropine, a muscarinic antagonist, is known since the 19th century to inhibit myopia development in children. One of its effects is that it stimulates choroidal thickening. Thicker choroids, in turn, have been linked to myopia inhibition. We used the atropine-stimulated choroidal response in the chicken to learn more about the time courses and amplitudes of the effects of atropine, as well as whether repeated applications lead to accumulation or desensitization. Methods: Intravitreal injections containing 250 µg atropine sulfate were performed in 1 eye around 10:00 in the morning, the fellow eye received vehicle. Chickens with bilateral vehicle injections served as controls. Choroidal thickness was measured over the day for every 2–3 h in alert animals, using spectral domain optical coherence tomography, with 3–5 independent measurements in each eye. Three experiments were done – (1) single injection and time course measured over 1 day, (2) single injection and time course measured over 4 days, and (3) daily injections and time course measured over 4 days for measuring the effects of atropine on vitreal, retinal, and choroidal dopamine, and 3,4-dihydroxyphenylacetic acid levels by using high-performance liquid chromatography with electrochemical detection. Results: Atropine induced an increase in choroidal thickness by about 60 percent, with a peak amplitude after about 2 h. The effect persisted only for a few hours and had nearly disappeared by evening. Initially, similar amounts of choroidal thickening were observed in vehicle-injected fellow eyes but recovery to baseline was faster. When atropine was injected daily for 4 days, choroids thickened every day with similar amplitudes and time courses, with no signs of either accumulation or desensitization effects. Interestingly, while dopamine release from the retina was stimulated by atropine and followed approximately, the time course of choroidal thickening, its tissue concentration dropped in the choroid. Conclusions: Even at relatively high intravitreal doses, effects of atropine on choroidal thickness remained transient, similar to its effects on retinal dopamine. With repeated application every day, the diurnal patterns of choroidal thickening could be reproduced for 4 days with similar amplitudes and time courses. The transient nature of the effects of atropine on the choroid may be relevant for application protocols of atropine against myopia.

Роль фтористого загрязнения в развитии миопии у детей младшего школьного возраста в условиях промышленного города Восточной Сибири

Роль фтористого загрязнения в развитии миопии у детей младшего школьного возраста в условиях промышленного города Восточной Сибири

Text Messaging for Parents of School-Aged Children in Controlling Myopia: A 1-Year, Randomized Controlled Trial and Additional 3-Years Follow Up

Background: Text messaging is effective in management of public health problems such as obesity, HIV, and childhood cataract, but no evidence is available for its effect on controlling myopia in children. Increasing time spent outdoors during school hours has been shown to retard myopia development in children but increasing time outdoors easily and effectively remains an important issue. The aims of this study were to investigate whether a mobile phone text message/short message service (SMS) for parents could increase light exposure and time outdoors in school-aged children, and what its long-term effect on controlling myopia. Methods: Of 3113 primary school students from the Anyang Childhood Eye Study, 268 grade 2 schoolchildren (mean age 8.4 years, 45% girls), recruited from October 2013 to May 2014, were randomly assigned (1:1) to a SMS group (n=135) where the parents received twice-daily text message reminders to take children outdoors, or a control group (n=133) for which the parents did not receive text messages. All children were instructed to wear portable light meters (HOBO, Pendant temp/light Part # UA-002-64) to record light exposure. A lower limit of 1000 lux in light intensity was defined for calculate time outdoors. Ocular examinations were performed annually by investigators masked to group allocation during the one-year intervention, and with three years of follow-up. The primary outcomes were changes in axial length and cycloplegic autorefraction. Findings: 261 children (97·4%) completed the Intervention period. At 1 year, the SMS group showed significantly greater light exposure than the control group at weekends (46 lux/day vs. 28 lux/day, P=0·02). Time outdoors was higher in the intervention group than in the control group at weekends (0·34 hours/day vs. 0·18 hours/day, P=0·03). Axial elongation was significantly smaller in the intervention group than in the control group during the trial (0·27 mm/y vs. 0·31 mm/y, P=0·03). Axial elongation and myopic shift remained smaller in the intervention group at the end of the 2nd year (0·39 mm vs. 0·46 mm, P<0·01; -0·69 D/y vs. -0·82 D/y, P=0·04) and 3rd year (0·30 mm vs. 0·35 mm, P<0·01; -0·47 D/y vs. -0·60 D/y, P=0·01). The main limitations of this study were the use of light meter not yet well validated for Chinese children and the cut-off of light intensity to define time outdoors Interpretation: The use of SMS increased children’s light exposure and time outdoors at weekends and resulted in slower axial elongation and myopia progression over a longer period. SMS in combination with wearable devices is promising for controlling myopia in populations of children. Trial Registration: The study has been registered in Chinese Clinical Trial Registry (ChiCTR-IOC-17010525). Funding Statement: Beijing talents foundation (2016000021469ZK28), the Capital health research and development of special (2020-4-2056), the Ministry of Science and Technology, the Major International (Regional) Joint Research Project of the National Natural Science Foundation of China (81120108007) and the National Natural Science Foundation of China (81300797). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The trial was approved by the Institutional Review Board of Beijing Tongren Hospital, Capital Medical University and followed the tenets of the Declaration of Helsinki. Written consent was obtained from at least one of the parents after the experimental procedures had been fully described to them.

Studies on retinal mechanisms possibly related to myopia inhibition by atropine in the chicken.

While low-dose atropine eye drops are currently widely used to inhibit myopia development in children, the underlying mechanisms are poorly understood. Therefore, we studied possible retinal mechanisms and receptors that are potentially involved in myopia inhibition by atropine. A total of 250μg atropine were intravitreally injected into one eye of 19 chickens, while the fellow eyes received saline and served as controls. After 1h, 1.5h, 2h, 3h, and 4h, eyes were prepared for vitreal dopamine (DA) measurements, using high-pressure liquid chromatography with electrochemical detection. Twenty-four animals were kept either in bright light (8500lx) or standard light (500lx) after atropine injection for 1.5h before DA was measured. In 10 chickens, the α2A-adrenoreceptor (α2A-ADR) agonists brimonidine and clonidine were intravitreally injected into one eye, the fellow eye served as control, and vitreal DA content was measured after 1.5h. In 6 chickens, immunohistochemical analyses were performed 1.5h after atropine injection. Vitreal DA levels increased after a single intravitreal atropine injection, with a peak difference between both eyes after 1.97h. DA was also enhanced in fellow eyes, suggesting a systemic action of intravitreally administered atropine. Bright light and atropine (which both inhibit myopia) had additive effects on DA release. Quantitative immunolabelling showed that atropine heavily stimulated retinal activity markers ZENK and c-Fos in cells of the inner nuclear layer. Since atropine was recently found to also bind to α2A-ADRs at doses where it can inhibit myopia, their retinal localization was studied. In amacrine cells, α2A-ADRs were colocalized with tyrosine hydroxylase (TH), glucagon, and nitric oxide synthase, peptides known to play a role in myopia development in chickens. Intravitreal atropine injection reduced the number of neurons that were double-labelled for TH and α2A-ADR. α2A-ADR agonists clonidine and brimonidine (which were also found by other authors to inhibit myopia) severely reduced vitreal DA content in both injected and fellow eyes, compared to eyes of untreated chicks. Merging our results with published data, it can be concluded that both muscarinic and α2A-adrenergic receptors are expressed on dopaminergic neurons and both atropine and α2A-ADR antagonists stimulate DA release whereas α2A-ADR agonists strongly suppress its release. Stimulation of DA by atropine was enhanced by bright light. Results are in line with the hypothesis that inhibition of deprivation myopia is correlated with DA stimulation, as long as no toxicity is involved.

Twenty-four hour ocular and systemic diurnal rhythms in children.

Ocular diurnal rhythms have been implicated in myopia, glaucoma, diabetes, and other ocular pathologies. Ocular rhythms have been well described in adults; however, they have not yet been fully examined in children. The goal of this study was to investigate ocular and systemic diurnal rhythms over 24h in children. Subjects, ages 5 to 14years (n=18), wore a light, sleep, and activity monitor for one week to assess habitual sleep/wake patterns, then underwent diurnal measurements every 4h for 24h. Measurements included blood pressure, heart rate, body temperature, intraocular pressure (IOP), ocular biometry, and optical coherence tomography imaging. Saliva was collected for melatonin and cortisol analysis. Mean ocular perfusion pressure was calculated from IOP and blood pressure. Central corneal thickness, corneal power, anterior chamber depth, lens thickness, vitreous chamber depth, and axial length were determined from biometry. Total retinal thickness, retinal pigment epithelium (RPE) + photoreceptor outer segment thickness, photoreceptor inner segment thickness, and choroidal thickness were determined for a 1mm diameter centred on the fovea. Subjects' amplitude and acrophase of diurnal variation for each parameter were determined using Fourier analysis, and mean acrophase was calculated using unit vector averaging. Repeated measures analysis of variance (ANOVA) showed that all parameters except anterior chamber depth exhibited significant variations over 24h (p≤0.005 for all). Axial length underwent diurnal variation of 45.25±6.30μm with an acrophase at 12.92h, and choroidal thickness underwent diurnal variation of 26.25±2.67μm with an acrophase at 1.90h. IOP was approximately in phase with axial length, with a diurnal variation of 4.19±0.50mmHg and acrophase at 11.37h. Total retinal thickness underwent a significant diurnal variation of 4.09±0.39μm with an acrophase at 15.04h. The RPE + outer segment layer was thickest at 3.25h, while the inner segment layer was thickest at 14.95h. Melatonin peaked during the dark period at 2.36h, and cortisol peaked after light onset at 9.22h. Ocular and systemic diurnal rhythms were robust in children and similar to those previously reported in adult populations. Axial length and IOP were approximately in phase with each other, and in antiphase to choroidal thickness. These findings may have important implications in myopia development in children.

Altered ocular parameters from circadian clock gene disruptions.

The pathophysiology of refractive errors is poorly understood. Myopia (nearsightedness) in particular both blurs vision and predisposes the eye to many blinding diseases during adulthood. Based on past findings of diurnal variations in the dimensions of the eyes of humans and other vertebrates, altered diurnal rhythms of these ocular dimensions with experimentally induced myopia, and evolving evidence that ambient light exposures influence refractive development, we assessed whether disturbances in circadian signals might alter the refractive development of the eye. In mice, retinal-specific knockout of the clock gene Bmal1 induces myopia and elongates the vitreous chamber, the optical compartment separating the lens and the retina. These alterations simulate common ocular findings in clinical myopia. In Drosophila melanogaster, knockouts of the clock genes cycle or period lengthen the pseudocone, the optical component of the ommatidium that separates the facet lens from the photoreceptors. Disrupting circadian signaling thus alters optical development of the eye in widely separated species. We propose that mechanisms of myopia include circadian dysregulation, a frequent occurrence in modern societies where myopia also is both highly prevalent and increasing at alarming rates. Addressing circadian dysregulation may improve understanding of the pathogenesis of refractive errors and introduce novel therapeutic approaches to ameliorate myopia development in children.