Epidemiological study on the transition of myopia. Prewar-wartime-postwar tendencies

Abstract

Different theories have been proposed as to the original causes of Myopia. These include heavy literary work, heredity, eye strain as well as some kinds of illumination and the habits of sleeping. Other theories have proven negative. Since the end of World War II the percentage of myopic students has increased with a present percentage of 15%. This includes the upper class student of primary schools, 28% and over for all junior high school students, 39% and over for all senior high school students, 50% and over for all college and university students.Recently physical examination data has been obtained which had been continued all through the war. This data contrasted with nation wide statistical data of physical examinations collected by the Dept. of Education enabled examination of each raw regression coefficient and the standard regression coefficient of the transition of Myopia. This was divided into the three periods of Prewar-Wartime and Postwar. The result was a mutual relationship between an annual change and occurrence in Prewar days as well as Wartime. It showed from -0.37 to -1.00 standard regression coefficient except for primary school students in agricultural districts. This tendency was especially remarkable regarding junior high school students upwards.On the contrary, in Postwar days the mutual relation reveals from 0.74 to 0.99 in remore locations the occurrence rate is decreasing in recent years.In view of these findings it has been concluded that Myopia conditions can be attributed to reading and studying habits rather than a nourishment or illumination situation.