Objective To understand the refractive progression of myopic school-aged children in ethnic minority areas of Yunnan and explore related factors.Methods Based on an existing cohort,a first follow-up survey was conducted from October 2020 to June 2021 involving 1,774 students selected from three ethnic minority areas:Dali City(Bai ethnic group),Lijiang Ancient Town(Naxi ethnic group),and Menghai County in Xishuangbanna(Dai and Hani ethnic groups).Among them,816 myopic school-aged children at baseline were selected as research subjects to analyze changes in refractive error(△SE)and the degree of refractive progression(classified as rapid △SE and slow △SE)over one year.Binary logistic regression was used to analyze the influencing factors of refractive progression.Results After one year of follow-up,the change in refractive error for myopic school-aged children was-0.63(-1.00,-0.25)D,with 518 children experiencing rapid △SE and 298 children experiencing slow △SE.Comparisons by educational stage indicated that Dai ethnic group children in primary school were more likely to experience rapid △SE than those in junior high school(P<0.05).Logistic regression results showed that school-age children of Naxi ethnic group(OR=1.879,95%CI:1.132～2.999),and those who used their eyes in the classroom during breaks(OR=1.541,95%CI:1.088～2.181)were at higher risk of rapid refractive progression(P<0.05).Children of school age who engage in outdoor activities for at least 3 hours during the day(OR=0.539,95%CI:0.340～0.853)and those who frequently consume animal liver(OR=0.596,95%CI:0.399～0.892)have a lower risk of rapid myopic progression(P<0.05).Conclusion Myopic school-aged children in ethnic minority areas of Yunnan exhibit rapid refractive progression,with significant ethnic differen-ces.The refractive progression in these children is closely related to lifestyle habits,highlighting the need for targeted myopia prevention and control measures and research for children and adolescents in ethnic minority areas of Yunnan.

Objective: To explore the pattern of change of axial length/curvatrue radius ratio (AL/CR) and associated factors in primary and secondary school students in Yunnan, so as to provide scientific basis and prospective guidance for early myopia intervention and control. Methods: A total of 685 students from grades 2 to 3 and grade 7 in 2 cities/counties in Yunnan Province were selected by multi stage stratified random cluster sampling method in 2020. All the participants were followed up twice with questionnaire of myopia related factors, uncorrected distance visual acuity, and refractive parameter measurement from October,2021 and March,2023,respectivelty. The distribution and change of AL/CR in different classes and groups were analyzed, and the influencing factos of AL/CR cumulative progression were explored using generalized linear model. Results: AL/CR ratio in primary school students was (2.95±0.09) at baseline, increased to (2.99±0.11) at the first follow up and (3.04±0.12) at the second follow up. AL/CR ratio in middle school students(3.08±0.13) at baseline, increased to (3.12±0.15) at the first follow up and (3.15±0.14) at the second follow up. The generalized linear model showed that after controlling for environmental factors, ethnicity ( β =-0.017) , cumulative progression of the SE ( β =-0.027) influenced the changes of AL/CR ratio among the primary school students, whereas the changes of AL/CR ratio were associated with baseline AL ( β =-0.005), baseline corneal curvatrue radius ( β =0.032) and cumulative progression of SE( β =-0.035) among middle school students ( P <0.05). Conclusions The AL/CR ratio of primary and secondary school students in Yunnan can be used to judge different refractive status types, but its variation is not only related to SE progression, but also affected by different ethnic groups and baseline ocular biological parameters. so the value of AL/CR application in assessing the progression of myopia needs to be further confirmed.

Objective To assess ocular biometric parameters among primary and secondary school students from Naxi,Bai and Han ethnic groups in Yunnan Province.Methods The school-based study was conducted in October 2020.A total of 724 second-,third-and seventh-graders were selected from Dali and Lijiang,where Bai and Naxi ethnic groups inhabit,using a stratified cluster sampling method to receive questionnaire surveys and eye examinations.Non-cycloplegic spherical equivalent(SE),axial length(AL),anterior chamber depth(ACD),corneal radius of curvature(CR),central corneal thickness(CCT),white-to-white(WTW)distance,and the AL/CR ratio were measured.Covariance analysis was used to examine the differences in SE and ocular biometric parameters in terms of ethnicity,sex and grade,while Pearson correlation was used to test the associations among the said indicators.Results There were no significant differences in daily outdoor time,screen time and sleep time among the three ethnic groups regardless of grades(all P＞0.05).The mean CCT of Naxi students was lower than that of Han and Bai students[grade 2 and grade 3:(542.48±39.76)μm vs.(553.81±31.83)μm and(559.27±32.79)μm;grade7:(538.86±34.91)μm vs.(547.41±33.55)μm and(548.26± 32.98)μm,all P＜0.05],while no significant differences were found in the other ocular biometric parameters among the three ethnic groups(all P＞0.05).Among the seventh-graders,the SE,AL and AL/CR ratio of Naxi students were signifi-cantly different from those of Han and Bai students(all P＜0.05).The AL,CR,ACD,CCT,WTW distance,and mean SE were lower in girls than in boys(all P＜0.05).Compared with grade 2 and grade 3,students of grade 7 had longer AL,deeper ACD and thinner CCT(all P＜0.05),while no significant differences were found in CR and WTW distance(all P＞0.05).Correlation analysis showed that the AL/CR ratio was highly correlated with SE(r=-0.78,P＜0.05).Conclu-sion Multiethnic primary and secondary school students may face similar environmental risks.Yet,disparities in ocular biometric parameters caused by ethnicity,sex and age should be noted.

Objective: To explore the related factors of myopia among children and adolescents in Yunnan Province, and to predict and evaluate the influencing factors, so as to provide a scientific theoretical basis for the prevention and control of myopia. Methods: From March 9 to 14, 2023, 848 students from 6 primary and secondary schools in Dali and Lijiang of Yunnan Province were selected by multi stage stratified random cluster sampling method for visual acuity detection and questionnaire survey on myopia related factors. Multivariate Logistic regression analysis was used to establish a Nomogram prediction model for the selected influencing factors. Results: The overall myopia rate of the respondents was 68.3%, the myopia rate of boys (63.4%) was lower than that of girls (72.9%), and the myopia rate of primary school students (46.7%) was lower than that of junior high school students (81.1%), and the difference was statistically significant（ χ 2=8.71, 108.07, P <0.05). Daily eye exercises, activities outside the teaching building during recess, having daily sleep time of 7-9 and >9 h, having both parents without myopia were negatively correlated with the occurrence of myopia in children and adolescents in Yunnan Province ( OR=0.64, 0.63, 0.56, 0.28, 0.48, P < 0.05 ). The reading and writing time after school ≥3 h per day and parents unrestricted time to play video games were positively correlated with myopia ( OR=1.94, 1.78, P <0.05). Based on the influencing factors, a Nomogram prediction model was established to quantitatively evaluate the risk of myopia. The results showed that greater risk for myopia was associated with sleep duration, parental history of myopia, and the time spent reading and writing after school every day. Conclusion Both genetic factors and environmental factors are related to myopia in children and adolescents. The prediction model of nomogram is beneficial for screening high risk factors of myopia and taking corresponding prevention and treatment measures.

Objective The objective of this study was to study the dosimetric characteristics and advantages of Non-coplanar IMRT techniques stereotactic body radiation therapy(SBRT)in the early stage of NSCLC.Methods Ten patients were selected with early stage of NSCLC.Treatment planning designed 9 fields coplanar IMRT and 9 fields Non-coplanar IMRT,respectively.Non-coplanar plans include five coplanar fields and four non-coplanar fields.Two group patients' plans compared V2.5,V5,V20,V25 of the whole lung,the average exposure doses of the whole lung,and the average exposure doses of the contralateral lung.The comparison of the other OARs include:spinal cord Dmax,heart Dmax,esophagus Dmax,trachea Dmax,chest wall Dmax and V30 of chest wall.At the meantime,we compared the conformal index of PTV(CI)and the homogenization index of PTV(HI).Results Non-coplanar plans reduced V20 of the whole lung(P=0.001),the average exposure dose of the contralateral lung(P=0.001),but V5 of the whole lung non-coplanar plans were increased than that in coplanar plans(P=0.002).Non-coplanar technology reduce max dose of spinal cord,esophagus,trachea,chest wall and V30 of chest wall(P=0.026,0.001,0.026,0.008,0.016).Heart Dmax of the non-coplanar plans was high in coplanar plans with no statistical significance difference(P=0.296).The conformal index of PTV of the non-coplanar plans was better(P=0.036),there was no difference in the homogenization index of PTV(P=0.254).Conclusion The stereotactic body radiation therapy of the early stage of NSCLC,the non-coplanar technology can effectively reduce exposure doses of the lung tissue and the other most OARs,also improve the conformal index of the PTV.The non-coplanar technology have possibility in reducing complications when compared with the coplanar technology and therefore has certain dosimetry advantage.