The sun. [volume] (New York [N.Y.]) 1833-1916, 1907-07-21
THE NEED or GLASSES.
Why and They should he Put On
sight In old Age.

-Si8nt I'm Otu
In many OF the headache cases which
an ooulist Is called on to investigate the
vision lie very good. In fact. says a writer
in the Medical Brief. II is what We call nor
NAL. or 1920.
TIT trouble In these cases ia the astIR-
matism. which is an uneven curvature of
the front Of the cornea. That lie, one merid-
ian. say the horizontal, is more curved than
the other. the perpendicular.
For these cases a cylindrical glass Ia what
is required to equalize things. A glass OF
this nature ~refracts only in one meridian.
By wearing proper glasses these cases
are relieved Of their headaches. Il n not
that the sight Is improved very much. or
sven at all in some. but IL relieves the eve
strain.
Astigmatism is supposed to be caused BY
the unequal pressure Of the eyeIids on the
oornea. This 10 oorneal astigmatisn. We
may also have astigmatism Of the lens Of
the eye, which is not 50 common.
It is most important for these people 70
wear the glasses straight, 80 that the lenses
are not tilted. II they are on wrong. II ID
az bad az II no glasses were worn.
People who get to be Is years old and
have never had any trouble with their eyes
find that in the evening; when reading, their
The book has to be held a little farther on
to see the letters. This condition 10 what
is called presbyopia. or old sight The
vision for distance may be normal. What
is needed 10 a convex glass which win mag
The condition Of presbyopia is physiologi-
cal and not pathological. The muscles
which O the lens 30 as to make the focus
for reading distance lose their power. Their
n ~ q a,.~@ItA 49, H. I
IL is necessary always to test persons
first for distance to sse il they are far sighted.
IL they are. the far sighted glass is added
to what may be needed for reading. That
lie. a person who lie not either near sighted
or far sighted AZ Is will require q I'D glass
to read with. II they were far siGbted.
say +2D. they would need a "a TO read
with.
II a person were near sighted. say I'D.
the condition ID different.
The person who at Is uses I'D for
distance needs only a I'D TO do near work
with, and at so years needle no gassss at
all for close work: Every five years from
IS on an extra +tD is required for reading
distance. At IS this same person would
still he using the -2D for distance and
rid for near.
We come across people 80 or 90 years
old who say they never use glasses. and
see as we'll as ever for distance and near.
This Is easily explained, One eye 10 neithsr
good for distance. The other 10 near
sighted and is used for near work. or
course these two eyes never can focus
together.
When a person has astigmatic troubles
IL is not necessary to wear glasses ell the
time. To use them for close work may be
enough. II. however, the headaches con-
tinue when a person 10 walking or sitting
around the house IL will h necessary 10
make constant use of them. In other
words. any time a person has headaches
wear the glasses. The amount Of astig-
quickly-that is. In a Few months. It may
get less or IL may increase. For this reason
a person might have headaches six month";
after getting glasses and wearing them ali
the time properly. The change In the cornoa
would explain the whole trouble.