中小学生正处在长身体长知识的时期。在他们成长发育的过程中,眼球也随之不断发育,由远视眼逐渐发展成正视眼。这时期,眼球的晶状体富有弹性,调节能力强,眼内压也容易发生变化,眼轴易于伸长,如果对眼睛的卫生注意不够,较易于发展成近视。根据近几年来的调查,一部分学校学生的近视率和近视程度有所增加。其中初中学生比小学生严重,高中学生又比初中学生严重。这说明,有些学校对教育学生预防眼睛近视,保护学生视力 Primary and secondary school students are in a period of long body knowledge. In the process of their growth and development, the eyeball also develops continuously, and the hypermetropia gradually develops into the emmetropic eye. During this period, the lens of the eyeball is full of elasticity, strong regulation ability, intraocular pressure is also easy to change, and the axial axis is prone to elongation. If the eye hygiene is not enough, it is easier to develop into myopia. According to recent surveys, some school students have increased myopia and myopia. Among them, junior high school students are more serious than primary school students, and high school students are more serious than junior high school students. This shows that some schools are protecting students against eye myopia and protecting students’ eyesight.