Longitudinal and Cross-Sectional Study of Refractive Changes in Pupils from 3 to 17 Years of Age

Abstract

To determine the prevalence of myopia and the mean change of progression of myopia in pupils from 3 to 17 years old in Japan, annual surveys were performed from 1984 to 1995. Between the cross-sectional study of 1985 and of 1995, the mean refractive error showed more myopic change, especially among pupils more than 11 years old. Among pupils more than 11 years old, the differences between 1985 and 1995 were statistically significant. The prevalence of myopia was greater in 1995 than in 1985 among pupils more than 8 years old. The prevalence of myopia increased from 51% to 68% over 10 years in students in the third grade of senior high school. A longitudinal 6-year study of the same students who entered the junior high school in 1984 showed an increase in the prevalence of myopia from 35.5% (the first year of junior high school) to 58.1% (the third year of senior high school). The mean change of progression of myopia was as follows: +1 D group, -0.14D/year; 0D group, -0.19D/ year; -1 to -5 D group, -0.40 D/year). The mean change in refractive error at the 5year follow-up examination was significantly different in males and females: -1.41 ± 1.25 D for males and -1.03 ± 1.07 D for females (paired t-test, P = 0.014). Our results showed an increase in myopia in school children. Further study will be required to find effective ways of decreasing the prevalence of myopia.