Page:Popular Science Monthly Volume 71.djvu/317

Rh or tenth year would probably escape with good eyes. Thus Cohn found that in the case of pupils 8 years old there were but 5 per cent., myopic, while of the pupils remaining the full 14 years, 63.6 per cent, were myopic. Investigations of the pupils of other cities of Germany resulted in similar findings. Investigations in America were not so numerous as those in Germany, but in general the results were the same until recent years.

Investigations carried on in Worcester, Massachusetts, in 1891, showed that in the second and third grades from 50 to 60 per cent, of the pupils possessed less than normal visual acuity. Investigations upon over 3,700 pupils of the Chicago public schools, in 1899, showed that the maximum of defective eyes was reached with pupils 9 years old. No one seems to have remarked upon this change in the grade at which the maximum destruction of the eyes is found. In fact the results seemed to have been looked upon as rather accidental and of no special significance.

Some months ago I asked myself these two questions. Is the maximum destruction of the eyes of the school children reached earlier than formerly? Secondly, if such is the case, what is the cause of it? In attempting to answer these questions I have tried to learn what recent investigators have found concerning eyes, and I have attempted personally to examine the eyes of children in schools which were significant. The data which I have secured lead me to conclude that the excessive destruction of the eyes begins several years earlier than was formerly the case in America, and earlier than is still the case in Germany and other foreign countries. As to the cause of the early injury of the eyes the results of my investigations are most significant. The highest per cent, of defective visual acuity I have thus far discovered was found in a room in which the pupils had been in school but 11 years. This is the room referred to above in which the average number of books read by each pupil during the preceding 12 months was 23. It may not surprise you when I tell you that 84 per cent, of these little innocents had defective vision. The schoolroom in which they were seated was unusually well provided with windows and had a south exposure. Unfortunately their teacher preferred a rather dimly-lighted room and made generous use of opaque shades with which the windows were provided. The light by which the pupils read in school was in most cases certainly better than the light which they had for their reading of books at home. Some of these children in their childish ignorance took books to bed with them, and upon awakening in the morning read before breakfast. It is probable that in most cases the children at home read during the evening twilight till it was too dark to tell one word from another. Then they would retire to some dark corner of a dimly lighted room and continue the reading till supper time or bed time. Young