·AIM:To investigate the poor eyesight situation of pupils and junior middle school students in Baoshan District,Shanghai,and to observe the impact of intervention on the development of myopia.·METHODS:Five schools were selected by randomized cluster sampling in Baoshan District,Shanghai.Eyesight was tested for all students in these five schools.Myopia was defined according to the criteria of Ophthalmonogy encyclopedia.Refraction examination was performed for the students with poor eyesight.Students from two schools with similar conditions were selected and divided in two groups,one intervention group and one control group.The eyesight was tested again after 6 months.·RESULTS:The prevalence of poor eyesight of students surveyed in Baoshan District was higher than the average prevalence in Shanghai.The prevalence of poor eyesight increased with the grade,and it was close to 50% for pupils and exceeded 70% for middle school students.The proportion of mild refractive error decreased and the proportion of severe refractive error increased with the grade,which raised from 10% of grade one to 30% of grade eight.There were neither significant differences of the prevalence of poor eyesight,nor significant differences of the proportion of refractive error between the first and the second eyesight tests for students in each grade.The comparison between the prevalence of poor eyesight before and after the intervention showed that the measures could not prevent the development of myopia,but increased the knowledge of eye protection for students.·CONCLUSION:The prevalence of poor eyesight and the proportion of severe refractive error increase with the grade for primary and middle school students.Enhanced behavior intervention has no significant effect on preventing the development of myopia.·