The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1941-01-23

Why do some people nave TO wear
glasses all the time and others for
reading only or close work?
Eye glasses are an artificial means
of focusing the zee. Such a complex
structure as the eye is often not per-
fectly adjusted or focused. 1t might be
compared with a telescope, which is
pulled in or pushed out to bring it to
a focus on the object viewed. The
focus of the eye is similarly affected
by the length of the seyeball, so that
an eyeban slightly longer than nor
NAL is focused for comparatively near
distance or is "nearsighted" while an
eyebau shorter than normal Is focused
for greater distance, and is refer
red to as "farsighted".
Just what causes eyestrain?
A variation of as little as one-six-
teenth of an inch in the length of the
eyeball is sufficient TO change the foe
us enough to reduce vision or cause
symptoms of eyestrain. Within the eye
is tiny lens which fortunately is Of
variable power, being controlled by a
ring of tiny muscles. By contractions
of this muscle ring to vary the power
of the lens, the eye can be adjusted to
small variations in focus. For example,
a farSighted eye may be focused on
near objects or a near-sighted eye on
distant objects, but there is a limit to
the amount Of such focusing the eye
can do without fatigue and eyestrain.
How are glasses for nearsightedness
different from those for farsightedness?
A lens for the correction of farsight-
edneSs is a convex or positive lens;
that is, it silortenS the focus of the
eye. A lens for nearsightedness is a
concave or negative lens, which length
ems the focus of the eye
Why do children who are nearsight-
ed have to wear their glasses all the
time both for distant an near vision?
Nearsighted persons of any age re-
quire glasses to obtain clear vision.
Children who are nearsighted require
correcting lenses to obtain anything
like normal distant vision. 1t is possible
that doing much close work or read
ing without this correction will tend
to make the nearsightedness become
worse. On the other hand, young per-
sons and children who are farsighted
may overcome this condition by ex-
ertion of the focusing power of the
lens within the eye. Great degrees of
farsightedness require constant over
exertton Of focusing power to that ia
tigue and eyestrain so reduce the eff
ficient use of the eyes.
What is astignatlsm end what do
glasses do for it?
AStigmatism is an irregularity in the |
curvature of the corner or surface of |
he eye. This irregularity prevents the
light rays which enter the eye from
coming to a focus, Lenses made for
he correction of astignlatisrn bring the
light rays to a clear focus. Astigma-
ism is structural abnormahty in the
,ye itself and Is not corrected Or al
cred in any way by these lenses.
Can babies be examined and fitted
With glasses and why should this be
Young children can be examined and
correct glasses fitted by the use of
means of measurement which are not
dependent on the response given by
he person being examined. Such ex-
limitations in young children are nee
Ssary only when some obvious diff
ulty with the eyes suggests probable
iced for glasses; for instance, cross
yed children are almost always eX-
remedy farsighted, and this farsighted-
less should be corrected as soon as it
S discovered even at the age of one
f two years. Another instance might
70 that of child who has become
ute nearSighted; unless nearsighted
hid Is given the benefit of correcting
enses his distance vision is lower than
formal and will interfere with his
roper progress in Schoi and play.
How does age affect the eyes?
In a young person the eye is so
lexible that it may be focused on dis
ant objects and also on near objects
UGH as reading or similar close work.