VISION UNDER ADVERSE CONDITIONS A BENEFIT TO THE EYES
A CCORDING to accepted ideas of ocular hygiene, it is important to protect the eyes from a great variety of influences which are often very diffi cult to avoid, and to which most people resign them selves with the uneasy sense that they are thereby "ruin ing their eyesight." Bright lights, artificial lights, dim lights, sudden fluctuations of light, fine print, reading in moving vehicles, reading lying down, etc., have long been considered "bad for the eyes," and libraries of literature have been produced about their supposedly direful effects. These ideas are diametrically opposed to the truth. When the eyes are properly used, vision under adverse conditions not only does not injure them, but is an actual benefit, because a greater degree of relaxa tion is required to see under such conditions than under more favorable ones. It is true that the conditions in question may at first cause discomfort, even to persons with normal vision; but a careful study of the facts has demonstrated that only persons with imperfect sight suffer seriously from them, and that such persons, if they practice central fixation, quickly become accustomed to them and derive great benefit from them.
Although the eyes were made to react to the light, a very general fear of the effect of this element upon the organs of vision is entertained both by the medical pro fession and by the laity. Extraordinary precautions are