The Cecil Whig. [volume] (Elkton, Md.) 1841-current, 1881-05-14

twenty anu JNtutN-iiNc years OF age ant
in certain cases to 4 later period. The
eye grows near-sighted by becoming dis
tended or stretched at its back part
whereby it gets longer optic axis. \
certain increase in the length of The opic
axis means a myopia calling for glass
thirty inches focus. This signifies that
the person, instead of being able to look
with distiuctness to an indefinite distance
namely. to the horizon.-has his dis
tinct vision bounded at thirty inches dis
tant 1t is very rare thing for persons
obliged to use Il concave glass eight inches
in focus not to have. in consequence OF
the thinning Of the back part of the eve
al Impairment of the integrity or health
fulneSs ofthe membranes around the opt ic
nerve. When they come to the use OF
glasses six inches in focus, the eyc-ball
being stretched only one-twelfth of an
inch, they are almost certain to have a
serious disease OF the membranes at the
back of the eye and degenerative changes
in the iclly-like substance called the Wit
reous humor, which fills up the principal
portion Of the interior Of the eye. Ii is
very common for persons who are near
sighted in the great degrees-that is
above ten-inch focuS-to have great
difficulty in the control OF their ewes so
as to bring them both to bear at once
upon near objects. as III reading or writ
ing. This happens sometimes among per-
sons with less degrees Of near-sigftcd-
ness. In the stronger degrees certain
diseased conditions are prone to arise.
namely. that shreds and PARTICLES get in
the vitrcous humor of the eye. and are
seen as black shadows, or clouds. or Other
objects Of various forms floating before
the sight. Cataract is a common result
Of the higher kinds of near-sightedneSs
toward middle life, and the nerve men,
hrane OF the eye, the retna. is also Ill
de To meet with deplorahle accident in
that it may be pulled from its place and
fluid intrude behind it. causing what is
known as detachment OF the rctina. The
effect of this is to destroy the sight en-
tircly over So much of the field of vision
as corresponds to the extent of the de-
tachmelt. Such II condition is not re-
covered from in more than ) per cent. OF
the cases. There may occur also erosion
~ Of At h,,
brane called the chofsid which is the
membrane furnishing the blood vessels
to most of the interior Of the eye, and
whose impairment damages the vision.
Among people who work much on close
objects myopa continues to increase after
twenty-five, but is usually arrested if they
,re il, ~Hu, health. Those who use 4 90.
inch glass or one OF high number do not
require the help of glasses for reading up
TO fifty or iifty-iive. Their distant vision.
however, does not grow any better. For
people who use a weaker glass the time
may arrive, say at sixty, when their dis
tant sight becomes good while for near
work they must use magnifying glasses.
And SO III proportion, persons using a 10
inch glass will reach time when they
may have to llsc a weak convex glass for
reading and weak concave glasses for
distance. while those who use glass of
5-inch focus will always be obliged to
use concave glasses for distance and may
use another but weaker concave glass for
reading. In later life. however. after
fifty, these strongly myopic people are
apt to find that their eyes have little
working power.
"Should children use glasses -
"When it appears that children in
schools have near-si@htrdness requir-
ing IA cOncave 36. they should always wear
glasses for blackboard and map exercises.
When they reach a degree amounting to
16 inches, and sometimes to a less degree.
they should wear glasses for reading as
well as for distance on the street and the
same holds good for all stronger cases.
Many near-sighted people having weak
eye muscles require weaker glasses for
reading than for distance. Others need
thicker than the outer edges and some
times vice versa. For some of these per-
sons operations on the muscles of the
eyes are necessary in order to give them
their proper relative power toward each
other. Many who have this muscular
difficulty suffer from headache and have
pain in their eyes and are ignorant of the
cause. In 1861. DIR. Cohn reported that
out of 10. 900 school children iii Germany
whose eyes were examined. nearly 6 per
cent. We're near sighted. \ few years
later, DR. Conrad found that nearly per
cent. of the 9. 036 school children whom
he examined in Germany were near-sight-
ed. ! think the percentage is not so high
in this country. Several hundred school
children have been examined here, from
sightedness was not SO prevalent in United
States as i'll Germany. Children in the
United States do not 60 to school so early.
and taking the population at large. their
health is better. Near-sightednesS rarely
begins with adults. 1t has been noticed
to begin. however, at sixty years Of ago
and then be connected with cataracts.
This distinction must be made in defin-
ing my0pia. 1t is not to be assumed that
the person who holds objects close to his
eyes is necessarily myopic. Almost any
kind of defective sight will oblige him
to do that, and it happens that some peo-
pie hold books very close TO their faces
who have extremely iiattenod instead
of elongated eyeA. These need convex
glasses. Persons recover from myopa
in the moderate degrees of the disease.
This comes about by hattening in tha
tense of the eye which dimi,,ishcs the
focal length of the eye but leaves the optic
axis unchanged. City life means indoor
life and occupation over books, newspa-
pers and writing, and consequently there
is more myopia in the city than in the
country. Those who live in y city gem
orally have less vigorous health than