There were considerable differences between 12 and 13, 12and 14 years old groups, in the refractive power of myopia.

• 近视眼按年龄和近视程度分类进行统计分析，随年龄增长近视屈光度升高：12岁组与13岁组间、12岁与14岁组间近视屈光度均有显著差异；