The Toledo chronicle. [volume] (Toledo, Tama County, Iowa) 1873-1924, 1877-09-13


, been made of it, SO that it is now one 4
! the most familiar ornaments of ladies an
. children Rome Cor. N. z. EceaSng Pos
MyopIa and the School Room.
It has long been fact, widely known
that myopia affects by preference thos
. who use their eyes constantly for nea
: work. And especially is it prevalen
among the educated and cultivated chsse
who employ their eyes during large por
, tion Of the day (and night too) in readin!
! or writing short sightedness is almost un
known among the unciyilized inhabitant
of the globe. Watch makers, jeweler
and some others whose business requires
close application Of the eyes form an ap
, parent exception to this rule, since th,
percentage OF short-sightedness in them il
not great The exception, however, il
only apparent. They always have q goot
light seldom work by artificial light, ane
nearly always use in their very fine wori
an eyerglass which removes pretty much
all the strain from the eye; and the in
vestigations of recent years 60 to show tina
the most frequent cause of myopia lies no
SO much in the continued use of the eyes
| ID Ill tuC uuldfOldUlC CIlCuIuStduCtS 1T
tending upon their use, and in particular
as regards Illumination
In order to an appreciative understand.
ing of the manner in which these Causes
tend to the production of myopia, brief
explanation of the condition of the eye in
short. sightedness is necessary. A myopic
state Of the eye may depend upon one Of
two conditions: 1st, Its refracting sur
faces may be too strongly curved-or,
2dly, The retina may be too far
EremOved from these surfaces-in
other words, the eye may be too
long. Either of these conditions will
have the effect to allow distinct image
of an object to be formed on the retina
only when the object is situated within a
comparatively short distance of the eyes
| The images of all objects farther remove ed
will be indistinct because the retina is no
longer in the focus, of rays of light COM
| ing from them. Now, the first of these
conditions (the excessive curvature of the
refracting surfaces) is rare, and, when
present, is generally congenital. The Sec
ond condition, though, beyond doubt,
sometimes congenital, is not commonly
SO, but is developed in, after life, and in
accordance with statistics the percentage
u US incIease 10 III uiIect propoltion 10
.ne continuous use OF tne eyes under un-
Tfe manner in which these circum-
stances bring about a change in the shape
of the ball is the following: .s1s
Given bad light, fine. work, or work
placed in such a position as requires a
bent position Of the head and body, and
let it be continued under these circum-
stances day after day, ornight after night,
and the result sooner or later must be q
congested condition OF the eyes, and espe-
oially, ,isit has been found. OF the inner
coats of the back part of the ball. This
congestion, if kept up for any consider
able length OF time, leads to a softening
of the tissues at that point, and eventually
to lehgthening OF the ball through CIV
ing, way ofthe parts to the lateral pressure
Of the muscles which move the eye. 7Fss Il
Such is the now accepted theory; but, 1
whether satisfactorily explanatory in ali
particulars or not, the fact yet remains,
which cannot be disputed, that there is a
eausative relation existing between such
circumstances and the production and In
crease of the degree of short sightedness
This being SO clearly demonstrated, the
course to pursue in order to prevent any
increase of existing myopia, and even its
production de mono, is plain, and this is
the point to which we would call the ear
nest attention of our educators.
The question Of first importance is nee
essarily that of light. And this is Just
where almost every school room that has
been examined has been found wanting.
\ The quantity Of light, in the first place,
is rarely sufficient. 1t has been deter
mined that the proportion which should
exist between the amount.of glass surface
lin square feet) and. the square surface of
the floor, is as to 3.5, or at least to 4.
In other words, for room 20 feet square
there should be from 20 to 80
square feet of glass, which amounts
10 between 500 and 900 square inch
es for each scholar, should 20 scholars
occupy it. In many Of the rooms exam
ined the proportion amounted from 1.1O
10 la. With insufficient light it is no
wonder that eyes having an inherent ten
dency to sightedness should give
way. Let, then, the directors of institu-
tions Of whatever kind where the eyes
and particularly the eyes o. cniidren-
are required TO 90 close work see tnat tne
square surface or tne ! Wndows 70 .h9
square surface OF tne noor Goes nos Iaii
below the proportion of 70 4.
But even when there y the proper
amount Of light, it is highly important
that It be rightly managed. ID the ma
.jority of rooms examtned the arrange
ment of the light was excssdingiy bad. in
q large number, what light tnere was
came from in front and OF course 1efL ol-
srectlY in the faces OF the cnlldfen; me
i'll effects OF this are not cSnnned alone 70
the eyes, but extend to other portions ol