The act of focalization is a muscular act and requires an effort, an
output of nervous energy, just as much in proportion as any other
muscular act, such as lifting a weight or shoving a saw or a jack plane.
The eye that is normally shaped forms pictures of objects, more than a few
feet distant, on its back wall without any muscular effort, and has to
focalize only when engaged in near work. But the oversighted eye is
compelled to do this extra work all the time, except when closed. If it
did not focalize, it would see indistinctly. This it refuses to do,
independently of any volition on the part of its owner. The eye that _can_
see distinctly _will_ see distinctly, no matter how great the strain, and
this by a volition apparently entirely its own. The results are headache,
vertigo, nausea, nervousness, irritability, and other disagreeable reflex
conditions, besides the pain and inflammation, and other symptoms
manifested in the eyes themselves. Of course, the only remedy in such
cases is glasses, and these glasses should be carefully selected by a
competent person, and should be worn as much of the time as is necessary
to relieve the eye strain. I find in _Taggart's Times_, February 5, 1888,
the following: "A French philosopher has said that a man who wears
gold-bowed spectacles always admires himself, and it would seem as though
spectacles were becoming a sort of badge of distinction, since young and
old who have the slightest excuse for using them put them on.