Lancaster daily intelligencer. [volume] (Lancaster, Pa.) 1864-1928, 1884-07-21
KAIiauHor TaEh hYE.
Some ra,laeiss Correcssa Relative 20 Huns
ViaaOD.


ssme Sailaeiss Corree,sa Relative 10 Human
VISION.
In . recent lecture Professor w. w.
eeeIy observed that persons speak Of their
syes being fatigued, meaning thereby that
the seeing portion of the brain Is fatigued,
but In that they are mistaken. 80 men
say their brains are tired. Brains seldom
become tired. The retina of the eye,
which Is part Of the brain and an offshot
from IL, hardly ever Is tired. The ia
tigue is In the inner and outer muscles
attached to the eye and In the muscle Of
accommodation. The eye ball, resting in
bed of fat, has attached TO II six muscles
ior turning 1t in any desired direction, and
the muscle attached to the side nearest the
nose and one at the outor angle OF the eye
should, in every normal eye, be balanced
They are used Ia oonverging the eye on
the object to be viewed, and the inner
muscles are used the more when the object
is the nearer. The muscle Of accommoda
tion 10 one which surrounds the lens of
the eve. When 1t ia wanted to gaze at
objects near at hand this muscle relsxes
aud allows the lens to thicken, increasing
its refractive power at the same time that
the muscles on the inner or nasal side Of
the eye contract aud direct the eyes to the
point gazed at. 1t Is in these muscles that
the fatigue is ielt, aud one finds relief in
closing the eyes or in gazing at objects at
q distance. The chief source OF fatigue is
the lack of balance in the two sets of inner
and outer muscles Of accommodation. 1t
may be set down that there is something
wrong when the eye becomes fatgued.
The defective eye, as 1t gives lout sooner,
is really safer from severe strains. The
usual indication of strain is redness of
the rim of the eyelid, betokening a cou.
gested state OF the inner surface, accom-
panied with some pain. When 1t is shown
that the eye is not equal to the work re
quired Of it, the proper remedy is not rest,
for that il fatal to its strength, but the use
OF glasses of sufficien power to render un-
necessary 80 much effort in accommodate.
ing the eye to vision. 1t is not good sense
to waste time in resting the eye, and that
practice does not strengthen it.
Eyes begin to age at about the tenth or
twelfth year of life, when they have reach.
cd their full development. At the age OF
forty five or fifty years the lenses cease to
thicken, when the pressure is removed and
their presby Dpia, or old sight, begins.
When o child is compelled to use or 70
auire the use Of glasses there is little rea
son to hope that it will outgrow the need,
but the person will use these glasses as a
basis, adding other glasses as he reaches
the age when old sight begins, or using
thicker glasses. DR.. Seely, however, men.
toned one case he had observed where a
child had outgrown the need Of glasses,
but in the meantime he had grown from a
small and puny child to large and well
developed man.
Second sight, or the apparent recovery
Of strength of vision, which is sometimes
seen in the aged, the lecturer explained
as q chauge,,.I eiongation, in the shape of
the eyehall by which the person became
> near sighted, accompanied by a change in
the lens caused by the appearance OF
cataract.