human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 ( 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 ( 
    Output:
    