视力低下、龋齿、沙眼是中小学生中常见的3种疾病，现对本市1991～1997年中小学生的该3种疾病的患病情况进行分析。1对象与方法1991～1997年每年9～11月，对全市各乡镇的中学和中心小学的学生进行健康体检，年体检率均在95％以上。视力低下采用对数视力表，双眼中心远视力低于5 Low vision, dental caries, trachoma is a common primary and secondary school students three kinds of diseases, the city of primary and secondary school students in 1991 to 1997 the prevalence of the three diseases were analyzed. 1 Subjects and methods From 1991 to 1997 From September to November each year, the city's township primary and secondary schools and primary health students, the annual physical examination rates were above 95%. Visual acuity using logarithmic visual acuity, binocular center distance vision less than 5