Effect of outdoor activity on myopia onset and progression in school-aged children in northeast china: the sujiatun eye care study Five-Year Clinical Trial on Atropine for the Treatment of Myopia 2: Myopia Control with Atropine 0.01% Eyedrops. A cohort study of incident myopia in Singaporean children. Ethnic variations in myopia and ocular biometry among adults in a rural community in China: the Yunnan minority eye studies. Effect of progressive addition lenses on myopia progression in Japanese children: a prospective, randomized, double-masked, crossover trial. Prevalence of Myopia and Its Risk Factors in Urban School Children in Delhi: The North India Myopia Study (NIM Study) Outdoor activity during class recess reduces myopia onset and progression in school children. Effect of Cycloplegia on the Refractive Status of Children: The Shandong Children Eye Study Outdoor activity reduces the prevalence of myopia in children. Risk Factors of Myopic Shift among Primary School Children in Beijing, China: A Prospective Study Disordered Sleep and Myopia Risk among Chinese Children Retardation of myopia in Orthokeratology (ROMIO) study: a 2-year randomized clinical trial. Associations between near work, outdoor activity, and myopia among adolescent students in rural China: the Xichang Pediatric Refractive Error Study report no. 2. Multifocal Contact Lens Myopia Control Atropine for the treatment of childhood myopia: safety and efficacy of 0.5%, 0.1%, and 0.01% doses (Atropine for the Treatment of Myopia 2). Myopia control using toric orthokeratology (TO-SEE study). Visual activity and its association with myopia stabilisation. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. A randomized trial using progressive addition lenses to evaluate theories of myopia progression in children with a high lag of accommodation. Family history, near work, outdoor activity, and myopia in Singapore Chinese preschool children [Myopia prevalence and influencing factor analysis of primary and middle school students in our country]. Light Exposure and Eye Growth in Childhood. Effect of Time Spent Outdoors at School on the Development of Myopia Among Children in China: A Randomized Clinical Trial. Myopia and myopic progression among schoolchildren: a three-year follow-up study. Population density and refractive error among Chinese children. Factors Related to the Progression of Myopia in Singaporean Children
Background Due to its high prevalence and associated sight-threatening pathologies , myopia has emerged as a major health issue in East Asia . The purpose was to test the impact on myopia development of a school-based intervention program aim ed at increasing the time student spent outdoors . Methods A total of 3051 students of two primary ( grade s 1 - 5 , aged 6 - 11 ) and two junior high schools ( grade s 7 - 8 , aged 12 - 14 ) in both urban and rural Northeast China were enrolled . The  intervention group ( n = 1735 ) unlike the control group ( n = 1316 ) was allowed two additional 20-min recess programs outside the classroom . A detailed question naire was administered to parents and children . Uncorrected visual acuity ( UCVA ) was measured using an E St and ard Logarithm Vision Acuity Chart ( GB11533 - 2011 ) at baseline , 6-month and 1-year intervals . A r and om sub sample ( n = 391 ) participated in the clinic visits and underwent  cycloplegia  at the beginning and after 1 year . Results The mean UCVA for the entire intervention group was significantly better than the entire control group after 1 year ( P < 0.001 ) . In the subgroup study , new onset of myopia and changes in refractive error towards myopia were direction during the study period was significantly lower in the intervention group than in the control group ( 3.70 % vs. 8.50 % , P = 0.048 ; -0.10 ± 0.65 D/year vs. -0.27 ± 0.52 D/year , P = 0.005 ) . Changes in axial length and IOP were also significantly lower following the intervention group ( 0.16 ± 0.30 mm/year vs. 0.21 ± 0.21 mm/year , P = 0.034 ; -0.05 ± 2.78 mmHg/year vs. 0.67 ± 2.21 mmHg/year , P = 0.006 ) . Conclusions Increasing outdoor activities prevented myopia onset and development , as well as axial growth and elevated IOP in children . Trial registration Current controlled trials NCT02271373 PURPOSE To compare the safety and efficacy of different concentrations of atropine eyedrops in controlling myopia progression over 5 years . DESIGN R and omized , double-masked clinical trial . PARTICIPANTS A total of 400 children originally r and omized to receive atropine 0.5 % , 0.1 % , or 0.01 % once daily in both eyes in a 2:2:1 ratio . METHODS Children received atropine for 24 months ( phase 1 ) , after which medication was stopped for 12 months ( phase 2 ) . Children who had myopia progression ( ≥-0.50 diopters [ D ] in at least 1 eye ) during phase 2 were restarted on atropine 0.01 % for a further 24 months ( phase 3 ) . MAIN OUTCOME MEASURES Change in spherical equivalent and axial length over 5 years . RESULTS There was a dose-related response in phase 1 with a greater effect in higher doses , but an inverse dose-related increase in myopia during phase 2 ( washout ) , result ing in atropine 0.01 % being most effective in reducing myopia progression at 3 years . Some 24 % , 59 % , and 68 % of children originally in the atropine 0.01 % , 0.1 % , and 0.5 % groups , respectively , who progressed in phase 2 were restarted on atropine 0.01 % . Younger children and those with greater myopic progression in year 1 were more likely to require re-treatment . The lower myopia progression in the 0.01 % group persisted during phase 3 , with overall myopia progression and change in axial elongation at the end of 5 years being lowest in this group ( -1.38±0.98 D ; 0.75±0.48 mm ) compared with the 0.1 % ( -1.83±1.16 D , P = 0.003 ; 0.85±0.53 mm , P = 0.144 ) and 0.5 % ( -1.98±1.10 D , P < 0.001 ; 0.87±0.49 mm , P = 0.075 ) groups . Atropine 0.01 % also caused minimal pupil dilation ( 0.8 mm ) , minimal loss of accommodation ( 2 - 3 D ) , and no near visual loss compared with higher doses . CONCLUSIONS Over 5 years , atropine 0.01 % eyedrops were more effective in slowing myopia progression with less visual side effects compared with higher doses of atropine PURPOSE To determine the risk factors of incident myopia in a school-based cohort study in Singaporean children . METHODS A 3-year prospect i ve cohort study was conducted in Singaporean school children aged 7 to 9 years in three schools at entry . Chinese children without myopia at baseline ( n = 994 ) were included in the analysis . The main outcome was incident myopia , defined as spherical equivalent ( SE ) at least -0.75 D based on cycloplegic autorefraction . Other definitions of incident myopia , at least -0.5 D and at least -1.0 D , were also assessed . RESULTS After controlling for school , age , gender , income , reading in books per week and intelligence quotient ( IQ ) test scores , we found the relative risk ( RR ) of incident myopia defined as -0.75 D to be 1.55 ( 95 % confidence interval [ CI ] 1.18 - 2.04 ) for two versus no myopic parents . The multivariate RR of myopia for IQ in the third versus first tertile was 1.50 ( 95 % CI , 1.19 - 1.89 ) . However , the RR of incident myopia was 1.01 ( 95 % CI , 0.97 - 1.05 ) for every unit increase in books read per week . Similar results were obtained with definitions of -0.5 and -1.0 D for incident myopia . CONCLUSIONS These data provide new prospect i ve evidence of essential links between parental myopia , IQ scores and subsequent myopia development . However , reading in books per week was not associated with incident myopia PURPOSE To determine the prevalence of myopia and ocular biometry in population -based sample s of ethnic Yi and Han people living in an inl and rural community in China . METHODS A r and om cluster sampling strategy was used to select ethnic Han and Yi adults aged 50 years or older living in Yunnan . Refractive error was determined by subjective refraction and ocular biometric parameters , including axial length ( AL ) , anterior chamber depth ( ACD ) , vitreous chamber depth ( VCD ) , and lens thickness ( LT ) , which were measured using an Echoscan . RESULTS Adults of Yi ethnicity had lower prevalence of myopia ( 10.3 % vs. 8.1 % ; P = 0.02 ) and high myopia ( 2.3 % vs. 1.6 % ; P = 0.10 ) than their counterparts of Han ethnicity . The prevalence of myopia increased with age ( P for trend < 0.05 ) , whereas the mean AL did not differ significantly among age groups in both ethnic groups ( both P for trend > 0.05 ) . In multivariate analysis , time spent outdoors was associated with myopia ( P = 0.003 ) and AL ( P < 0.001 ) but not high myopia ( P = 0.33 ) . No interaction effect was detected between ethnicity and other risk factors on myopia ( all P > 0.05 ) . Adjustment for lens nuclear opacity score reduced the excess prevalence of myopia in Han ethnicity by 37.5 % . CONCLUSIONS There was little evidence showing that ethnic disparities existed in the prevalence and risk factors between the major and minor ethnic groups living in the same communities in rural China . The " cohort effect " on myopia observed in many other population s was not seen in this study PURPOSE This prospect i ve , r and omized , double-masked , crossover trial was conducted to evaluate the clinical effectiveness of progressive addition lenses ( PALs ) compared with single-vision lenses ( SVLs ) on myopia progression in Japanese children . METHODS Ninety-two children fulfilling the inclusion criteria ( age : 6 - 12 years , spherical equivalent refractive errors : -1.25 to -6.00 D ) were r and omly allocated to either 18 months of wearing PALs ( near addition : + 1.50 D ) followed by 18 months of SVLs ( group 1 ) , or 18 months of wearing SVLs followed by 18 months of wearing PALs ( group 2 ) , and were followed up for 3 years ( two-stage crossover design ) . The primary outcome measure was myopia progression , as determined by cycloplegic autorefraction . RESULTS Eighty-six ( 93 % ) children completed both treatment periods . A mixed-model , two-way analysis of variance ( ANOVA ) performed using 3-year data identified a significant treatment effect of PALs compared with SVLs ( P = 0.0007 ) , with a mean 18-month difference of 0.17 D ( 95 % CI : 0.07 - 0.26 D ) . This analysis also indicated a significant period effect ( P = 0.0040 ) and a significant treatment-by-period interaction ( P = 0.0223 ) : Group 1 showed a slower myopia progression than did group 2 . CONCLUSIONS The use of PALs slowed myopia progression , although the treatment effect was small , as previously reported in ethnically diverse children in the United States . The significant treatment-by-period interaction suggests that early application of PALs would probably be more beneficial for these age and refraction ranges ( is rct n.org number , 28611140 ) Purpose Assess prevalence of myopia and identify associated risk factors in urban school children . Methods This was a cross-sectional study screening children for sub-normal vision and refractive errors in Delhi . Vision was tested by trained health workers using ETDRS charts . Risk factor question naire was filled for children with vision < 6/9.5 , wearing spectacles and for a subset ( 10 % ) of r and omly selected children with normal vision . All children with vision < 6/9.5 underwent cycloplegic refraction . The prevalence of myopia < -0.5 diopters was assessed . Association of risk factors and prevalence of myopia was analyzed for children with myopia and r and omly selected non myopic children and adjusted odds ratio values for all risk factors were estimated . Results A total number of 9884 children were screened with mean age of 11.6 + 2.2 years and 66.8 % boys .  Prevalence of myopia was 13.1 % with only 320 children ( 24.7 % ) wearing appropriate spectacles . Mean myopic spherical error was -1.86 + 1.4 diopters . Prevalence of myopia was higher in private schools compared to government schools ( p<0.001 ) , in girls vs. boys ( p = 0.004 ) and among older ( > 11 years ) children ( p<0.001 ) . There was a positive association of myopia with study ing in private schools vs. government schools ( p<0.001 ) , positive family history ( p < 0.001 ) and higher socio-economic status ( p = 0.037 ) . Positive association of presence of myopia was observed with children study ing/reading > 5 hours per day ( p < 0.001 ) , watching television > 2 hours / day ( p < 0.001 ) and with playing computer/video/mobile games ( p < 0.001 ) . An inverse association with outdoor activities/playing was observed with children playing > 2 hours in a day . Conclusion Myopia is a major health problem in Indian school children . It is important to identify modifiable risk factors associated with its development and try to develop cost effective intervention strategies PURPOSE The aim of this study was to investigate the effect of outdoor activity during class recess on myopia changes among elementary school students in a suburban area of Taiwan . DESIGN Prospect i ve , comparative , consecutive , interventional study . PARTICIPANTS Elementary school students 7 to 11 years of age recruited from 2 nearby schools located in a suburban area of southern Taiwan . INTERVENTION The children of one school participated in the interventions , whereas those from the other school served as the control group . The interventions consisted of performing a recess outside the classroom ( ROC ) program that encouraged children to go outside for outdoor activities during recess . The control school did not have any special programs during recess . MAIN OUTCOME MEASURES Data were obtained by means of a parent question naire and ocular evaluations that included axial length and cycloplegic autorefraction at the beginning and after 1 year . RESULTS Five hundred seventy-one students were recruited for this study , of whom 333 students participated in the interventional program , and 238 students were in the control school . At the beginning of the study , there were no significant differences between these 2 schools with regard to age , gender , baseline refraction , and myopia prevalence ( 47.75 % vs. 49.16 % ) . After 1 year , new onset of myopia was significantly lower in the ROC group than in the control group ( 8.41 % vs. 17.65 % ; P<0.001 ) . There was also significantly lower myopic shift in the ROC group compared with the control group ( -0.25 diopter [D]/year vs. -0.38 D/year ; P = 0.029 ) . The multivariate analysis demonstrated that the variables of intervention of the ROC program and higher school year proved to be a protective factor against myopia shift in nonmyopic subjects ( P = 0.020 and P = 0.017 , respectively ) . For myopic subjects , school year was the only variable significantly associated with myopia progression ( P = 0.006 ) . CONCLUSIONS Outdoor activities during class recess in school have a significant effect on myopia onset and myopic shift . Such activities have a prominent effect on the control of myopia shift , especially in nonmyopic children . FINANCIAL DISCLOSURE(S ) The author(s ) have no proprietary or commercial interest in any material s discussed in this article Purpose To determine the effect of 1 % cyclopentolate on the refractive status of children aged 4 to 18 years . Methods Using a r and om cluster sampling in a cross-sectional school-based study design , children with an age of 4–18 years were selected from kindergardens , primary schools , junior and senior high schools in a rural county and a city .  Auto-refractometry was performed before and after inducing cycloplegia which was achieved by 1 % cyclopentolate eye drops . Results Out of 6364 eligible children , data of 5999 ( 94.3 % ) children were included in the statistical analysis . Mean age was 10.0±3.3 years ( range : 4–18 years ) . Mean difference between cycloplegic and non-cycloplegic refractive error ( DIFF ) was 0.78±0.79D ( median : 0.50D ; range : -1.00D to + 10.75D ) . In univariate analysis , DIFF decreased significantly with older age ( P<0.001;correlation coefficient r:-0.24 ) , more hyperopic non-cycloplegic refractive error ( P<0.001;r = 0.13 ) and more hyperopic cycloplegic refractive error ( P<0.001;r = 0.49 ) . In multivariate analysis , higher DIFF was associated with higher cycloplegic refractive error ( P<0.001 ; st and ardized regression coefficient beta:0.50 ; regression coefficient B : 0.19 ; 95 % confidence interval ( CI ) : 0.18 , 0.20 ) , followed by lower intraocular pressure ( P<0.001 ; beta : -0.06 ; B : -0.02 ; 95%CI : -0.03 , -0.01 ) , rural region of habitation ( P = 0.001 ; beta : -0.04 ; B : -0.07 ; 95%CI : -0.11 , -0.03 ) , and , to a minor degree , with age ( P = 0.006 ; beta : 0.04 ; B : 0.009 ; 95%CI : 0.003 , 0.016 ) . 66.4 % of all eyes with non-cycloplegic myopia ( ≤-0.50D ) remained myopic after cycloplegia while the remaining 33.6 % of eyes became emmetropic ( 18.0 % ) or hyperopic ( 15.7 % ) under cycloplegia . Prevalence of emmetropia decreased from 37.5 % before cycloplegia to 19.8 % after cycloplegia while the remaining eyes became hyperopic under cycloplegia . Conclusions The error committed by using non-cycloplegic versus cycloplegic refractometry in children with mid to dark-brown iris color decreased with older age , and in parallel manner , with more myopic cycloplegic refractive error . Non-cycloplegic refractometric measures lead to a misclassification of refractive error in a significant proportion of children OBJECTIVE To assess the relationship of near , midworking distance , and outdoor activities with prevalence of  myopia in school-aged children . DESIGN Cross-sectional study of 2 age sample s from 51 Sydney schools , selected using a r and om cluster design . PARTICIPANTS One thous and seven hundred sixty-five 6-year-olds ( year 1 ) and 2367 12-year-olds ( year 7 ) participated in the Sydney Myopia Study from 2003 to 2005 . METHODS Children had a comprehensive eye examination , including cycloplegic refraction . Parents and children completed detailed question naires on activity . MAIN OUTCOME MEASURES Myopia prevalence and mean spherical equivalent ( SE ) in relation to patterns of near , midworking distance , and outdoor activities .  Myopia was defined as SE refraction < or = -0.5 diopters ( D ) . RESULTS Higher levels of outdoor activity ( sport and leisure activities ) were associated with more hyperopic refractions and lower myopia prevalence in the 12-year-old students . Students who combined high levels of near work with low levels of outdoor activity had the least hyperopic mean refraction ( + 0.27 D ; 95 % confidence interval [ CI ] , 0.02 - 0.52 ) , whereas students who combined low levels of near work with high levels of outdoor activity had the most hyperopic mean refraction ( + 0.56 D ; 95 % CI , 0.38 - 0.75 ) . Significant protective associations with increased outdoor activity were seen for the lowest ( P = 0.04 ) and middle ( P = 0.02 ) tertiles of near-work activity . The lowest odds ratios for myopia , after adjusting for confounders , were found in groups reporting the highest levels of outdoor activity . There were no associations between indoor sport and myopia . No consistent associations between refraction and measures of activity were seen in the 6-year-old sample . CONCLUSIONS Higher levels of total time spent outdoors , rather than sport per se , were associated with less myopia and a more hyperopic mean refraction , after adjusting for near work , parental myopia , and ethnicity Objective : To evaluate factors associated with myopic shift among primary school children . Methods : In a one-year prospect i ve school-based study , 5052 children from ten schools were enrolled using a multi-stage r and om cluster approach . The baseline examination included non-cycloplegic auto-refractometry and question naire interview . Measurements were repeated at the follow-up . Results : Among 5052 students at baseline investigated , 4292 students ( 85.0 % ) returned for the follow-up examination .  The mean refractive error ( -1.13±1.57 diopters ) had changed -0.52±0.73 diopters from the baseline to the follow-up examination . 2170 ( 51.0 % ) had a rate of significant myopic shift ( significant myopic shift is defined as the change of spherical equivalent of the refraction ≤ -0.50D between the follow-up and baseline measures ) . We confirmed that common associated factors ( older age , parental myopia , lower refractive status at baseline , shorter reading distance and lower frequency of outdoor activities during class recesses ) were associated with greater shift towards myopia . After controlling for age , sex , region of habitation , parental myopia and refractive status at baseline , greater shift towards myopia was independently associated with distance from near-work ( OR=1.48 , 95 % CI=1.26 - 1.74 , P<0.001 ) and longer time outdoors for leisure ( OR=0.87 , 95 % CI=0.78 - 0.97 , P<0.013 ) . Conclusion : Greater shift towards myopia was independently associated with modifiable factors ( distance from near-work and longer time outdoors for leisure ) might suggest that encouraging children to go outside for outdoor activities during class recess and after school may be a promising and feasible intervention against myopia development Purpose Disordered sleep and myopia are increasingly prevalent among Chinese children . Similar pathways may be involved in regulation of both sleep cycles and eye growth . We therefore sought to examine the association between disordered sleep and myopia in this group . Methods Urban primary school children participating in a clinical trial on myopia and outdoor activity underwent automated cycloplegic refraction with subjective refinement .  Parents answered questions about children 's sleep duration , sleep disorders ( Children 's Sleep Habits Question naire [ CSHQ ] ) , near work and time spent outdoors . Results Among 1970 children , 1902 ( 96.5 % , mean [ st and ard deviation SD ] age 9.80 [ 0.44 ] years , 53.1 % boys ) completed refraction and question naires . Myopia < = -0.50 Diopters was present in both eyes of 588 ( 30.9 % ) children ( 1329/3804 = 34.9 % of eyes ) and 1129 children ( 59.4 % ) had abnormal CSHQ scores ( > 41 ) . In logistic regression models by eye , odds of myopia < = -0.50D increased with worse CSHQ score ( Odds Ratio [ OR ] 1.01 per point , 95 % Confidence Interval [ CI ] [ 1.001 , 1.02 ] , P = 0.014 ) and more night-time sleep ( OR 1.02 , 95 % CI [ 1.01 , 1.04 , P = 0.002 ] , while male sex ( OR 0.82 , 95 % CI [ 0.70 , 0.95 ] , P = 0.008 ) and time outdoors ( OR = 0.97 , 95 % CI [ 0.95 , 0.99 ] , P = 0.011 ) were associated with less myopia . The association between sleep duration and myopia was not significant ( p = 0.199 ) for total ( night + midday ) sleep . Conclusions Myopia and disordered sleep were both common in this cohort , but we did not find consistent evidence for an association between the two . Trial Registration clinical trials.gov PURPOSE This single-masked r and omized clinical trial aim ed to evaluate the effectiveness of orthokeratology ( ortho-k ) for myopic control . METHODS A total of 102 eligible subjects , ranging in age from 6 to 10 years , with myopia between 0.50 and 4.00 diopters ( D ) and astigmatism not more than 1.25D , were r and omly assigned to wear ortho-k lenses or single-vision glasses for a period of 2 years . Axial length was measured by intraocular lens calculation by a masked examiner and was performed at the baseline and every 6 months . This study was registered at Clinical Trials.gov , number NCT00962208 . RESULTS In all , 78 subjects ( 37 in ortho-k group and 41 in control group ) completed the study .  The average axial elongation , at the end of 2 years , were 0.36 ± 0.24 and 0.63 ± 0.26 mm in the ortho-k and control groups , respectively , and were significantly slower in the ortho-k group ( P < 0.01 ) . Axial elongation was not correlated with the initial myopia ( P > 0.54 ) but was correlated with the initial age of the subjects ( P < 0.001 ) . The percentages of subjects with fast myopic progression ( > 1.00D per year ) were 65 % and 13 % in younger ( age range : 7 - 8 years ) and older ( age range : 9 - 10 years ) children , respectively , in the control group and were 20 % and 9 % , respectively , in the ortho-k group . Five subjects discontinued ortho-k treatment due to adverse events . CONCLUSIONS On average , subjects wearing ortho-k lenses had a slower increase in axial elongation by 43 % compared with that of subjects wearing single-vision glasses . Younger children tended to have faster axial elongation and may benefit from early ortho-k treatment . ( Clinical Trials.gov number , NCT00962208 . ) OBJECTIVE To study the associations between near work , outdoor activity , and myopia among children attending secondary school in rural China . METHODS Among a r and om cluster sample of 1892 children in Xichang , China , subjects with an uncorrected acuity of 6/12 or less in either eye ( n = 984 ) and a 25 % sample of children with normal vision ( n = 248 ) underwent measurement of refractive error . Subjects were administered a question naire on parental education , time spent outdoors , and weekly time spent engaged in and preferred working distance for a variety of near-work activities . RESULTS Among 1232 children with refraction data , 998 ( 81.0 % ) completed the near-work survey . Their mean age was 14.6 years ( SD , 0.8 years ) , 55.6 % were girls , and 83.1 % had myopia of -0.5 diopters or less ( more myopia ) in both eyes .  Time and diopter-hours spent on near activities did not differ between children with and without myopia . In regression models , time spent on near activities and time outdoors were unassociated with myopia , adjusting for age , sex , and parental education . CONCLUSIONS These and other recent results raise some doubts about the association between near work and myopia . Additional efforts to identify other environmental factors associated with myopia risk and that may be amenable to intervention are warranted Purpose Previous studies on soft multifocal contact lens myopia control published in the peer- review ed literature reported findings of noncommercial contact lenses worn for 1 year or less . This study sought to determine the progression of myopia and axial elongation of children fitted with commercially available distance center soft multifocal contact lenses for 2 years . Methods Eight- to eleven-year-old children with −1.00 D to −6.00 D spherical component and less than 1.00 D astigmatism were fitted with  soft multifocal contact lenses with a + 2.00 D add ( Proclear Multifocal “ D ” ; CooperVision , Fairport , NY ) . They were age- and gender-matched to participants from a previous study who were fitted with  single-vision contact lenses  ( 1 Day Acuvue ; Vistakon , Jacksonville , FL ) . A-scan ultrasound and cycloplegic autorefraction were performed at baseline , after 1 year , and after 2 years . Multilevel modeling was used to compare the rate of change of myopia and axial length between single-vision and soft multifocal contact lens wearers . Results Forty participants were fitted with soft multifocal contact lenses , and 13 did not contribute complete data ( 5 contributed 1 year of data ) . The adjusted mean ± st and ard error spherical equivalent progression of myopia at 2 years was −1.03 ± 0.06 D for the single-vision contact lens wearers and −0.51 ± 0.06 for the soft multifocal contact lens wearers ( p < 0.0001 ) . The adjusted mean axial elongation was 0.41 ± 0.03 and 0.29 ± 0.03 for the single-vision and soft multifocal contact lens wearers , respectively ( p < 0.0016 ) . Conclusions Soft multifocal contact lens wear result ed in a 50 % reduction in the progression of myopia and a 29 % reduction in axial elongation during the 2-year treatment period compared to a historical control group . Results from this and other investigations indicate a need for a long-term r and omized clinical trial to investigate the potential for soft multifocal contact lens myopia control PURPOSE Our previous study , Atropine for the Treatment of Myopia 1 ( ATOM1 ) , showed that atropine 1 % eyedrops were effective in controlling myopic progression but with visual side effects result ing from cycloplegia and mydriasis . The aim of this study was to compare efficacy and visual side effects of 3 lower doses of atropine : 0.5 % , 0.1 % , and 0.01 % . DESIGN Single-center , double-masked , r and omized study . PARTICIPANTS A total of 400 children aged 6 - 12 years with myopia of at least -2.0 diopters ( D ) and astigmatism of -1.50 D or less . INTERVENTION Children were r and omly assigned in a 2:2:1 ratio to 0.5 % , 0.1 % , and 0.01 % atropine to be administered once nightly to both eyes for 2 years .  Cycloplegic refraction , axial length , accommodation amplitude , pupil diameter , and visual acuity were noted at baseline , 2 weeks , and then every 4 months for 2 years . MAIN OUTCOME MEASURES Myopia progression at 2 years . Changes were noted and differences between groups were compared using the Huber-White robust st and ard error to allow for data clustering of 2 eyes per person . RESULTS The mean myopia progression at 2 years was -0.30±0.60 , -0.38±0.60 , and -0.49±0.63 D in the atropine 0.5 % , 0.1 % , and 0.01 % groups , respectively ( P=0.02 between the 0.01 % and 0.5 % groups ; between other concentrations P > 0.05 ) . In comparison , myopia progression in ATOM1 was -1.20±0.69 D in the placebo group and -0.28±0.92 D in the atropine 1 % group . The mean increase in axial length was 0.27±0.25 , 0.28±0.28 , and 0.41±0.32 mm in the 0.5 % , 0.1 % , and 0.01 % groups , respectively ( P < 0.01 between the 0.01 % and 0.1 % groups and between the 0.01 % and 0.5 % groups ) . However , differences in myopia progression ( 0.19 D ) and axial length change ( 0.14 mm ) between groups were small and clinical ly insignificant . Atropine 0.01 % had a negligible effect on accommodation and pupil size , and no effect on near visual acuity . Allergic conjunctivitis and dermatitis were the most common adverse effect noted , with 16 cases in the 0.1 % and 0.5 % atropine groups , and no cases in the 0.01 % group . CONCLUSIONS Atropine 0.01 % has minimal side effects compared with atropine at 0.1 % and 0.5 % , and retains comparable efficacy in controlling myopia progression PURPOSE This nonr and omized clinical study aim ed to investigate the effectiveness of toric orthokeratology ( ortho-k ) for myopia control in myopic children with moderate-to-high astigmatism METHODS We enrolled 80 subjects ( aged 6 - 12 years ; ortho-k , 43 ; control , 37 ) with myopia of 0.50 to 5.00 diopters ( D ) , and with-the-rule astigmatism of -1.25 to -3.50 D , and unremarkable ocular and general conditions . Data collection , including visual acuity , subjective and objective refraction , axial length , corneal topography , and biomicroscopy examination , was performed every 6 months during the 24-month study period . Results from the right eye or the eye with higher astigmatism were reported . RESULTS A total of 35 ortho-k and 23 control subjects completed the study successfully . Subjects in both groups demonstrated axial elongation ( P < 0.001 ) . The average axial elongation at the end of study was 0.31 ± 0.27 and 0.64 ± 0.31 mm in the ortho-k and control groups , respectively ( P < 0.001 ) . At the end of 24 months , axial elongation  in ortho-k subjects was 52 % slower than that in the control group . Axial elongation was correlated significantly with the initial age of the subjects ( P = 0.02 ) and treatment assigned ( P = 0.04 ) , but not with sex , initial myopia , initial refractive cylinder , or initial corneal toricity ( P > 0.08 ) . CONCLUSIONS Toric ortho-k lenses can slow axial elongation effectively in myopic children with moderate-to-high astigmatism . ( Clinical Trials.gov number , NCT00978692 . ) PURPOSE To evaluate the association between outdoor and nearwork activities at baseline and myopia stabilisation by age 15 in the Correction of Myopia Evaluation Trial ( COMET ) . METHODS Correction of Myopia Evaluation Trial enrolled 469 children ( ages : 6 - 11 years ) with spherical equivalent myopia between -1.25 and -4.50 D , who were r and omised to progressive addition or single vision lenses and followed for 5 years in their original lenses .  At baseline , families recorded the child 's  outdoor and nearwork activities  for 3 days within a week . Weekly hours spent in nearwork and outdoor activities were calculated for each participant . Refractions collected over 11 years were fit using the Gompertz function to determine each participant 's myopia stabilisation age . Myopia for each child was then categorized as stable/not stable by age 15 . RESULTS Half ( 233/469 ) of participants had usable baseline activity diaries and refraction data that could be fit with the Gompertz function , 59.7 % ( 139/233 ) had stable myopia by age 15 and 40.3 % had myopia that was not yet stable . The frequency of stable myopia was similar for the two categories ( median split ) of outdoor activities : 60 % ( 71/118 ) for ≤9.0 hours/week(-1 ) and 59 % ( 68/115 ) for > 9.0 hours/week(-1 ) . 56 % ( 64/114 ) of children reporting > 21.0 h of baseline weekly nearwork activity had stable myopia by age 15 compared to 63 % ( 75/119 ) with ≤21.0 h of near work ( adjusted OR = 0.74 ; 95 % CI : 0.43 - 1.29 ) . Using baseline nearwork as a continuous variable , the multivariable odds ratio for the association between baseline nearwork hours and stabilisation by age 15 is 0.98 : 95 % CI : 0.96 - 1.00 , a result trending towards significance . CONCLUSION While time spent in outdoor activities in childhood does not appear to be related to myopia stabilisation by age 15 , less near work activity might potentially be associated with myopia stabilisation by that age OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity PURPOSE To compare the effect of wearing , then ceasing to wear , progressive addition lenses ( PALs ) versus single vision lenses ( SVLs ) on myopia progression in children with high accommodative lag to evaluate accommodative lag and mechanical tension as theories of myopia progression . METHODS Eighty-five children ( age range , 6 - 11 years ) with spherical equivalent ( SE ) cycloplegic autorefraction between -0.75 D and -4.50 D were r and omly assigned to wear SVLs or PALs for 1 year ; all children wore  SVLs a second year . Children had high accommodative lag and also had near esophoria if their myopia was greater than -2.25 D SE . The primary outcome after each year was the previous year 's change in SE . RESULTS When the children were r and omly assigned to SVLs or PALs , the adjusted 1-year changes in SE were -0.52 D ( SVL group ) and -0.35 D ( PAL group ; treatment effect = 0.18 D ; P = 0.01 ) . When all children wore SVLs the second year , there was no difference in myopia progression between SVL and former PAL wearers ( 0.06 D ; P = 0.50 ) . Accommodative lag was not associated with myopia progression . CONCLUSIONS The statistically significant , but clinical ly small , PAL effect suggests that treatments aim ed at reducing foveal defocus may not be as effective as previously thought in myopic children with high accommodative lag . Finding no evidence of treatment loss after discontinuing PAL wear supports hyperopic defocus-based theories such as accommodative lag ; however , not finding an association between accommodative lag and myopia progression is inconsistent with the PAL effect being due to decreased foveal blur during near work . ( Clinical Trials.gov number , NCT00335049 . ) Aims To investigate the risk factors for myopia , including near work and outdoor activity , in Singapore Chinese preschool children . Methods A cross-sectional study , with disproportionate r and om sampling by 6-month age groups , of 3009 Singapore Chinese children aged 6–72 months was performed . Information on family history , near work and outdoor activity was obtained . Spherical equivalent refraction ( SER ) was assessed . Results Children with two myopic parents were more likely to be myopic ( adjusted OR=1.91 ; 95 % CI 1.38 to 2.63 ) and to have a more myopic SER ( regression coefficient=−0.35 ; 95 % CI −0.47 to −0.22 ) than children without myopic parents . For each 1 cm taller height , the SER was more myopic by 0.01 dioptres . Neither  near work nor outdoor activity was associated with preschool myopia . Conclusions A family history of myopia was the strongest factor associated with preschool myopia . In contrast , neither  near work nor outdoor activity  was found to be associated with early myopia . These data suggest that genetic factors may play a more substantial role in the development of early-onset myopia than key environmental factors 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 r and om cluster sampling method , 20 000 students of 90 schools including key and non-key primary or junior or senior school in country and city of sh and ong , qinghai , yunnan , Shanghai and wenzhou were r and om 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 question naires were received . By r and om 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 χ(2 ) = 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 PURPOSE The purpose of this study was to examine the relationship between objective ly measured ambient light exposure and longitudinal changes in  axial eye growth in childhood . METHODS A total of 101 children ( 41 myopes and 60 nonmyopes ) , 10 to 15 years of age participated in this prospect i ve longitudinal observational study . Axial eye growth was determined from measurements of ocular optical biometry collected at four study visits over an 18-month period . Each child 's mean daily light exposure was derived from two periods ( each 14 days long ) of objective light exposure measurements from a wrist-worn light sensor . RESULTS Over the 18-month study period , a modest but statistically significant association between greater average daily light exposure and slower axial eye growth was observed ( P = 0.047 ) . Other significant predictors of axial eye growth in this population included children 's refractive error group ( P < 0.001 ) , sex ( P < 0.01 ) , and age ( P < 0.001 ) . Categorized according to their objective ly measured average daily light exposure and adjusting for potential confounders ( age , sex , baseline axial length , parental myopia , nearwork , and physical activity ) , children experiencing low average daily light exposure ( mean daily light exposure : 459 ± 117 lux , annual eye growth : 0.13 mm/y ) exhibited significantly greater eye growth than children experiencing moderate ( 842 ± 109 lux , 0.060 mm/y ) , and high ( 1455 ± 317 lux , 0.065 mm/y ) average daily light exposure levels ( P = 0.01 ) . CONCLUSIONS In this population of children , greater daily light exposure was associated with less axial eye growth over an 18-month period . These findings support the role of light exposure in the documented association between time spent outdoors and childhood myopia IMPORTANCE Myopia has reached epidemic levels in parts of East and Southeast Asia . However , there is no effective intervention to prevent the development of myopia . OBJECTIVE To assess the efficacy of increasing time spent outdoors at school in preventing incident myopia . DESIGN , SETTING , AND PARTICIPANTS Cluster r and omized trial of children in grade 1 from 12 primary schools in Guangzhou , China , conducted between October 2010 and October 2013 . INTERVENTIONS For 6 intervention schools ( n = 952 students ) , 1 additional 40-minute class of outdoor activities was added to each school day , and parents were encouraged to engage their children in outdoor activities after school hours , especially during weekends and holidays .  Children and parents in the 6 control schools ( n = 951 students ) continued their usual pattern of activity . MAIN OUTCOMES AND MEASURES The primary outcome measure was the 3-year cumulative incidence rate of myopia ( defined using the Refractive Error Study in Children spherical equivalent refractive error st and ard of ≤-0.5 diopters [ D ] ) among the students without established myopia at baseline . Secondary outcome measures were changes in spherical equivalent refraction and axial length among all students , analyzed using mixed linear models and intention-to-treat principles . Data from the right eyes were used for the analysis . RESULTS There were 952 children in the intervention group and 951 in the control group with a mean ( SD ) age of 6.6 ( 0.34 ) years .  The cumulative incidence rate of myopia was 30.4 % in the intervention group ( 259 incident cases among 853 eligible participants ) and 39.5 % ( 287 incident cases among 726 eligible participants ) in the control group ( difference of -9.1 % [ 95 % CI , -14.1 % to -4.1 % ] ; P < .001 ) . There was also a significant difference in the 3-year change in spherical equivalent refraction for the intervention group ( -1.42 D ) compared with the control group ( -1.59 D ) ( difference of 0.17 D [ 95 % CI , 0.01 to 0.33 D ] ; P = .04 ) . Elongation of axial length was not significantly different between the intervention group ( 0.95 mm ) and the control group ( 0.98 mm ) ( difference of -0.03 mm [ 95 % CI , -0.07 to 0.003 mm ] ; P = .07 ) . CONCLUSIONS AND RELEVANCE Among 6-year-old children in Guangzhou , China , the addition of 40 minutes of outdoor activity at school compared with usual activity result ed in a reduced incidence rate of myopia over the next 3 years . Further studies are needed to assess long-term follow-up of these children and the generalizability of these findings . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00848900 PURPOSE To discuss the factors that might explain the rate of myopic progression and the degree of myopia after a 3-year follow-up among schoolchildren with myopia . METHODS Myopic progression among 238 schoolchildren was followed up in a r and omized clinical trial of myopia treatment . The associations between the explanatory factors and myopic progression and the final value of the spherical equivalent after the follow-up were studied by analysis of variance and regression analysis . RESULTS Myopia progressed faster among girls than boys . According to the regression models for the boys , 25 % of the variation of myopic progression and 57 % of the final spherical equivalent could be explained by initial spherical equivalent , age at receiving first spectacles , time spent on sports and outdoor activities , and on reading and close work . Among the girls , 30 % of myopic progression could be explained by age at receiving first spectacles , time spent on reading and close work , and reading distance . Similarly , 49 % of the final spherical equivalent could be explained by age at receiving first spectacles , initial spherical equivalent , time spent on reading and close work , and reading distance . The rest of the variations could not be explained by the variables measured in this study . CONCLUSIONS The factors with the most significant relationships to myopic progression were sex , age of onset , and degree of myopia at the beginning of the follow-up . Myopic progression and final myopia were related to time spent on reading and close work and to reading distance but not , however , to accommodation stimulus PURPOSE China is urbanizing rapidly , and the prevalence of myopia is high . This study was conducted to identify the reasons for observed differences in the prevalence of myopia among urban versus rural Chinese children . METHODS All children with uncorrected acuity of 6/12 or worse and a 50 % r and om sample of children with vision better than 6/12 at all secondary schools in mixed rural-urban Liangying Township , Guangdong , underwent cycloplegic refraction , and provided data on age , gender , parental education , weekly near work and time outdoors , and urban development level of respondents ' neighborhoods ( 12-item question naire ) . Population density of 32 villages and urban zones in Liangying was calculated from census figures ( mean population density , 217 persons/km(2 ) ; range , 94 - 957 ; mean for Guangdong , 486 ) . RESULTS Among 5844 eligible children , 4612 ( 78.9 % ) had parental consent and completed examinations ; 2957 were refracted per protocol , and 2480 ( 83.9 % ) of these had question naire data . Those with completed examinations were more likely to be girls ( P < 0.001 ) , and question naire respondents were more myopic ( P = 0.02 ) , but otherwise did not differ significantly from nonrespondents . In multivariate models , older age ( P < 0.001 ) , more near work ( P = 0.02 ) , and higher population density ( P = 0.003 ) , but not development index , parental education , or time outdoors were significantly associated with more myopic refractive error . CONCLUSIONS Higher population density appears to be associated with myopia risk , independent of academic activity , time spent outdoors , familial educational level , or economic development , factors that have been thought to explain higher myopia prevalence among urban children . Mechanisms for this apparent association should be sought Purpose To examine the possible factors related to the progression of myopia in Singapore children . Methods One hundred fifty-three Singapore children aged 6 to 12 years were recruited to participate in a concurrent cohort study of the risk factors for the progression of myopia .  Socioeconomic status , outdoor activity  , and near-work activity were documented in a face-to-face clinic interview . The changes in cycloplegic subjective refraction and autorefraction were ascertained with the use of a Nidek ARK 900 over a 2-year period . Results The average rate of progression of myopia as measured by subjective refraction was −0.59 D per year ( 95 % confidence interval −0.52 , −0.66 ) . Younger children and children who were more myopic at the beginning ( refractive error worse than −2.0 D ) of the study had higher myopia progression rates . Conclusions Myopia progression was faster for younger children and for children who had more severe myopia at baseline . Socioeconomic status and near-work activity were not related to myopia progression
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 .