Outdoor time is considered to reduce the risk of developing myopia. The purpose is to evaluate the evidence for association between time outdoors and (1) risk of onset of myopia (incident/prevalent myopia); (2) risk of a myopic shift in refractive error and c) risk of progression in myopes only. A systematic review followed by a meta-analysis and a dose–response analysis of relevant evidence from literature was conducted. PubMed, EMBASE and the Cochrane Library were searched for relevant papers. Of the 51 articles with relevant data, 25 were included in the meta-analysis and dose–response analysis. Twenty-three of the 25 articles involved children. Risk ratio (RR) for binary variables and weighted mean difference (WMD) for continuous variables were conducted. Mantel–Haenszel random-effects model was used to pool the data for meta-analysis. Statistical heterogeneity was assessed using the I2 test with I2 ≥ 50% considered to indicate high heterogeneity. Additionally, subgroup analyses (based on participant's age, prevalence of myopia and study type) and sensitivity analyses were conducted. A significant protective effect of outdoor time was found for incident myopia (clinical trials: risk ratio (RR) = 0.536, 95% confidence interval (CI) = 0.338 to 0.850; longitudinal cohort studies: RR = 0.574, 95% CI = 0.395 to 0.834) and prevalent myopia (cross-sectional studies: OR = 0.964, 95% CI = 0.945 to 0.982). With dose–response analysis, an inverse nonlinear relationship was found with increased time outdoors reducing the risk of incident myopia. Also, pooled results from clinical trials indicated that when outdoor time was used as an intervention, there was a reduced myopic shift of −0.30 D (in both myopes and nonmyopes) compared with the control group (WMD = −0.30, 95% CI = −0.18 to −0.41) after 3 years of follow-up. However, when only myopes were considered, dose–response analysis did not find a relationship between time outdoors and myopic progression (R2 = 0.00064). Increased time outdoors is effective in preventing the onset of myopia as well as in slowing the myopic shift in refractive error. But paradoxically, outdoor time was not effective in slowing progression in eyes that were already myopic. Further studies evaluating effect of outdoor in various doses and objective measurements of time outdoors may help improve our understanding of the role played by outdoors in onset and management of myopia.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/aos.13403

Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review.

PURPOSE Myopia is an important cause of correctable visual impairment worldwide. Genetic and environmental factors contribute to its development. The population of Chinese university students consists of approximately 30 million young people characterized by academic excellence and similar ages. To date, little is known about their refractive status. Our study is designed to investigate the prevalence of myopia in this specific population. METHODS This is a cross-sectional study of myopia among university students in Shanghai, China; 5083 students from Donghua University were enrolled. All participants first responded to a detailed questionnaire, including questions on ethnicity, birth date, and family history, and then undertook a standardized ophthalmologic examination, including visual acuity, a slit-lamp examination, and non-cycloplegic autorefraction. RESULTS The mean spherical equivalent refraction (SER) of the university students was -4.1 diopters (D). Of the subjects 95.5% were myopic (SER < -0.50 D), 19.5% were highly myopic (SER < -6.0 D), and only 3.3% were emmetropic (-0.5 D ≤ SER ≤ 0.5 D). The postgraduates were more myopic than the undergraduates (96.9% and 94.9%, respectively). Being female (-4.1 ± 2.4 D in female versus -3.8 ± 2.4 D in male subjects), of Han ethnicity (-4.1 ± 2.4 D in Han versus -3.4 ± 2.2 D in minorities), and of older age were associated with a higher probability of myopia only in the undergraduate population. CONCLUSIONS The prevalence of myopia and high myopia in this university student population was high. The refractive status of this population deserves further attention.

High prevalence of myopia and high myopia in 5060 Chinese university students in Shanghai.

Importance Time spent in outdoor activities has decreased owing to home confinement for the coronavirus disease 2019 (COVID-19) pandemic. Concerns have been raised about whether home confinement may have worsened the burden of myopia owing to substantially decreased time spent outdoors and increased screen time at home. Objective To investigate the refractive changes and prevalence of myopia in school-aged children during the COVID-19 home confinement. Design, Setting, and Participants A prospective cross-sectional study using school-based photoscreenings in 123 535 children aged 6 to 13 years from 10 elementary schools in Feicheng, China, was conducted. The study was performed during 6 consecutive years (2015-2020). Data were analyzed in July 2020. Exposures Noncycloplegic photorefraction was examined using a photoscreener device. Main Outcomes and Measures The spherical equivalent refraction was recorded for each child and the prevalence of myopia for each age group during each year was calculated. The mean spherical equivalent refraction and prevalence of myopia were compared between 2020 (after home confinement) and the previous 5 years for each age group. Results Of the 123 535 children included in the study, 64 335 (52.1%) were boys. A total of 194 904 test results (389 808 eyes) were included in the analysis. A substantial myopic shift (approximately −0.3 diopters [D]) was found in the 2020 school-based photoscreenings compared with previous years (2015-2019) for younger children aged 6 (−0.32 D), 7 (−0.28 D), and 8 (−0.29 D) years. The prevalence of myopia in the 2020 photoscreenings was higher than the highest prevalence of myopia within 2015-2019 for children aged 6 (21.5% vs 5.7%), 7 (26.2% vs 16.2%), and 8 (37.2% vs 27.7%) years. The differences in spherical equivalent refraction and the prevalence of myopia between 2020 and previous years were minimal in children aged 9 to 13 years. Conclusions and Relevance Home confinement during the COVID-19 pandemic appeared to be associated with a significant myopic shift for children aged 6 to 8 years according to 2020 school-based photoscreenings. However, numerous limitations warrant caution in the interpretation of these associations, including use of noncycloplegic refractions and lack of orthokeratology history or ocular biometry data. Younger children’s refractive status may be more sensitive to environmental changes than older ages, given the younger children are in a critical period for the development of myopia.

/pdf/progression-of-myopia-in-school-aged-children-after-covid-19-6l1hg8qbj3.pdf

Progression of Myopia in School-Aged Children After COVID-19 Home Confinement.

Fabrication of fibrous MXene nanoribbons (MNRs) membrane with efficient performance for oil-water separation

Background: Morphological changes of the vasculature system in patients with myopia have been observed by Doppler ultrasound and fundus fluorescein angiography (FFA); however, these studies have limitations. Doppler ultrasound provides low-resolution images which are mainly obtained from visualized large vessels, and FFA is an invasive examination. Optic coherence tomography (OCT) angiography is a noninvasive, high-resolution measurement for vascular density. The purpose of this study was to investigate the change of vascular density in myopic eyes using OCT angiography. Methods: This cross-sectional study includes a total of 91 eyes from 47 participants including control, moderate, and high myopia that were evaluated by OCT angiography. Patients with myopia were recruited from the Refractive Department, Shenzhen Aier Eye Hospital, from August 5, 2015 to April 1, 2016. Emmetropic eyes were from healthy volunteers. The vascular density at macula and optic disc regions, ganglion cell complex (GCC) thickness, and retinal nerve fiber layer (RNFL) thickness were measured. Their relationships with axial length (AL) and refractive error were analyzed. One-way analysis of variance (ANOVA), Pearson's correlation, and generalized estimating equation were used for statistical analysis. Results: Both superficial and deep macular vascular density were highest in control (25.64% ± 3.76% and 37.12% ± 3.66%, respectively), then in moderate myopia (21.15% ± 5.33% and 35.35% ± 5.50%, respectively), and lowest in high myopia group (19.64% ± 3.87% and 32.81% ± 6.29%, respectively) ( F = 13.74 and 4.57, respectively; both P P P = 0.040), independent of spherical equivalent. The vascular density in optic disc region had no difference among the three groups, and it was not associated with AL, spherical equivalent, or RNFL thickness. Conclusion: Our results suggested that with the increase of myopia, the vascular density decreased in macular region, but not in optic disc region.

Reduced Macular Vascular Density in Myopic Eyes.

Background: Gender is one of the risk factors accounting for the high prevalence of adolescent myopia. Considerable research results have shown that myopia incidence of female is higher than that of male. This study aimed to analyze the correlation between ocular parameters and serum estrogen level and to investigate the vision changes along with estrogen change in menstrual cycle of adolescent females. Methods: A total of 120 young females aged between 15 and 16 years, diagnosed with myopia were recruited. Spherical lens, cylindrical lens, axis, interpupillary distance (IPD), and vision in each tested eye of the same subject were measured by automatic optometry and comprehensive optometry, with repetition of all measurements in the menstrual cycle of the 2 nd or 3 rd days, 14 th days, and 28 th days, respectively. Serum estradiol (E 2 ) levels were assayed by chemiluminescence immunoassay at the same three times points of the menstrual cycle mentioned above. Results: In young females with myopia, the spherical lens showed a statistically significant difference among all different time in menstrual cycle (all P P χ 2 = 6.35, P = 0.042). The vision during the 14 th and 28 th day was higher compared to that on the 2 nd or 3 rd days ( P = 0.021). Serum E 2 levels were significantly different at different time points in menstrual cycle ( P 2 levels reached its maximum value on the 14 th day and the minimum value on the 2 nd or 3 rd day. Conclusions: In adolescent females, the spherical lens and other related ocular parameters vary sensitively with different levels of E 2 in menstrual cycle. Vision in late menstrual stage is significantly higher than that in premenstrual stage.

Relevant factors of estrogen changes of myopia in adolescent females.

Tannic acid (TA)-based coating modified membrane enhanced by successive inkjet printing of Fe3+ and sodium periodate (SP) for efficient oil-water separation

Objective To understand and address our vision changes in primary and secondary students,in order to explore the prevention of juvenile myopia to provide a response and suggestions.Methods A random cluster sampling method,random sample of 90 rural and urban schools in Shandong,Qinghai,Yunnan,Shanghai and Wenzhou from May 2008 to September 2009,including 20 000 students(per province,4000×5)from elementary school and junior high school of focus and non-focus,primary 11 246,junior high school students 3673,high school 4220,of which 11 177 were from the urban students,rural students in 7962,aged 6 to 19 years old,male to female ratio is basically the same.For myopia and related survey.a total of 19,139 valid questionnaires were recovered.Using SPSS 13.0 software statistical analysis,different regions and different grades was used to compare the prevalence of myopia X~2 test.using Logistic regression analysis on the major risk factors for myopia.Results The survey are as follows,the prevalence of myopia in primary was 13.7%;the prevalence of myopia in junior high was 42.9%,the prevalence of myopia in high school was 69.7%.The highest rate of myopia prevalence of primarv school students in Shandong was 19.7%,the lowest was 11.9% in Qinghal,Shanghai,Wenzhou and Yunnan are similar;prevalence myopia of junior high in Wenzhou up to 50.6%,followed by Shanghai,and 47.2%,the lowest was 33.6%in Qinghai;the highest prevalence of myopia and high school students in Shandong,reaching 87.3%,followed by 72.0%in Wenzhou,and the lowest was 60.2% in Shanghai.Conclusion This survey shows that the prevalence of myopia of China's primary and secondary schools in coastal was higher than areas of mainland,in developed regions was higher than in less developed regions,and the plateau region and the strong ultraviolet light similar to the plain areas.Provincial prevalence of myopia increased from primary to high school continued the same trend.

Key words: 
Youth; Myopia; Prevalence; Influencing factors

[Analysis of correlative factors and prevalence on China's youth myopia].

Objective
To investigate the quantitative changes of the serum sex hormone levels in juvenile myopia patients.


Methods
In January 2013, investigation of wenzhou middle school 822 adolescents, including 432 male patients and 390 female patients were involved in the study Visual acuity ≥ 5 was set as the normal value. The subjects were divided into two groups, the myopia group and the non-myopia group. Chemiluminescence immunoassay analyzer was used to detect the subjects' sex hormone concentration of estradiol (E2), testosterone (T), follicle stimulating hormone (FSH) and luteinizing hormone (LH).


Results
The follicle stimulating hormone and luteinizing hormone of the female patients were significantly higher than those of male counterparts (P<0.01); among the two groups consisting female myopia and non-myopia patients, a significant difference in luteinizing hormone and follicle stimulating hormone was shown (P<0.05); the distinct differences in the level of luteinizing hormone and testosterone level showed in the male myopia group and non-myopia group were of outstanding statistics significance (P<0.01), showing the result that the level of sex hormone in myopia group was higher than that in the non-myopia group.


Conclusion
A close relationship perhaps between the level of sex hormone with gender differences and juvenile myopia is confirmed.


Key words: 
Myopia; Sex hormone; Clinical study; Juvenile

Analysis on the relationship between adolescent myopia and serum sex hormone

Objectives
To explore the situation and the affect factors of myopia and scientificalness and effectiveness of eye exercises about primary and middle school students.


Methods
Through the random cluster sampling method, 20 000 students of 90 schools including key and nonkey primary or junior or senior school in country and city of shandong,qinghai, yunnan,Shanghai and wenzhou were random selected.Primary students is 11 246 junior students is 3673 senior students is 4220.We surveyed related situation of eye exercises, myopia.a total of 19 139 valid questionnaires were received.By random sampling stratification method, freshmen were selected and retrospective surveyed.929 freshmen have normal vision when they graduated primary school.338 freshmen have normal vision when they graduated primary school. 2 groups are considered analysis object, and Myopic students of the former in junior school stages and the latter in senior school stages are considered case group, normal vision are considered control group, and then through the Logistic multiple stepwise regression analysis, a regression analysis model is established.


Results
This survey show that myopia prevalence was 13.7% of primary students, 42.9% of junior students, 69.7% of senior students.According to the significant P<0.001, Rsquare=0.14, the result shows that the model has the significant statistical significance.Among the influence factors, whether to long-term excessive use eye is the most significant, and following by outdoor activities and gender.A chi-square test χ2=0.371 and P=0.543 show that doing eye exercises was not statistically significant to prevalence of myopia.


Conclusion
The influence factors are changed, and the preventive methods should be adjusted with the social environment.


Key words: 
Myopia; Prevalence; Sickness impact profile; Primary and middle students

Hong-li Xie

Papers

Relevant factors of estrogen changes of myopia in adolescent females.

Tannic acid (TA)-based coating modified membrane enhanced by successive inkjet printing of Fe3+ and sodium periodate (SP) for efficient oil-water separation

[Analysis of correlative factors and prevalence on China's youth myopia].

Analysis on the relationship between adolescent myopia and serum sex hormone

Myopia prevalence and influencing factor analysis of primary and middle school students in our country