Page:Popular Science Monthly Volume 12.djvu/96

 86 near-sight tends to effect the elongation of the visual axis. But while there might be no disagreement among oculists as to the fact that the practices and conditions named do thus tend, there may not be a consonance so general as to the precise process in every case A few general suggestions, however, are submitted:

1. The rationale of the effect of the premature use of books, etc., during the more plastic condition of the eye is sufficiently obvious.

2. A prolonged tension of the sight lessens the muscular elasticity.

3. The contraction and consequent thickening of the muscles which pull the two eyes inward, so as to focalize the sight upon a near object, causes a side-pressure, and a corresponding transverse or length-wise protrusion. The nearer the object, the stronger must be this action of the muscles, and the more marked the effect.

4. The prone position of the head causes the blood to settle in the eyeballs, increasing the tension of the fluids, exciting inflammation and consequent softening of the coatings, and resulting in permanent distention.

The attentive reader cannot have failed to observe that we have enumerated causes of injury to the eyes from study, other than those which produce near-sight. Of these, only one seems to require reference—the effect of bad air in the school-room.

Dr. Loring read a paper in February last before the Medico-Legal Society of New York, answering four questions relating to the care of the eyesight, which had been submitted to him by that Society. The first of the series inquires the effect of bad air on the sight. His reply, given at some length, supports the statement herein made.

In a recent conversation with the writer, Dr. Loring advocated examinations of the sight of all children when they first enter school, and at such subsequent stages of their education as might seem desirable. The position of a child's seat relatively to the blackboard, etc., would often be governed by such an examination. He thought, too, that glasses would be recommended in some cases by the examining oculist—a permanent official he would have him to be—and that, if necessary, they should be furnished at the public expense, or out of some special fund; the glasses to be worn during school-hours at least, if not continuously. He related the circumstance of a lad having been recently brought to him by his father from the West. An examination verified the boy's statement that he could see to read usually very well; but that sometimes, in a moment, his sight would be so affected that reading became impossible. This had led to his repeated punishment at school, his averment of inability not being credited by his teacher.