Changes of axial length in primary and secondary school students in Yunnan and associated factors / 中国学校卫生

ABSTRACT

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.