Northern tribune. [volume] (Cheboygan, Mich.) 1875-1885, 1885-02-05
NORTHERN TRIBUNE.
THURSDAY. FEBRUARY 5. 1885.
HUMAN VISION.

Something About the Eyesight, which
Should be Read and Remembered.
Persons speak of their eyes being ia
tigusd, meaning thereby that the sec
ing portion Of the brain is fatigued, but
In that says DIR. W. W. Sesly, they are
mistaken. So men say their brains are
tired. The retina of the eye, which is a
part of the brain and an Off-shoOt from
il, hardly ever is tired. Tho fatigue is
in the inner and outer muscles attached
to the eye and in tho muscle of accOmO-
dalton. The sye-ball resting in bed Of
fat. has attached to il six muscles for
turning it In any desired direction, and
the muscle attached to the side nearest
the nose and one at the outer angle of
the eye should, in every normal eye, DO
balanced. They are used in c0nverging
the eye on the object to DO viewed, and
the inner muscles are used the more
when the object is nearer. The muscle
of accommodation is one which sur
rounds the lens of the eye. When it is
wanted to gaze at objects near at hand,
this "a ussle relaxes and allows the lens
to thicken, increasing its retroactive pow
er at the same time that the muscles ON
the inner or nasal side Of the eye con-
tract or direct the eyes to the point gaZ-
ed at. IL is in these muscles that the
| fatigue ia felt, and ono finds relief in
closing he eyes or i'm gazing at objects
at a distance. The chief source of ia
| tigns Is the luck of balance in the two
sets of inner and outer muscles OF ae-
comm edaticn. 1t may be set down that
there is something wrong when the eye
becomes fatigued. The defective eye, as
it gives out sooner, is really safer from Sc
we're strains. The usual indication OF
strains is redness of the rim Of the eye.
lid, bet0kening a cOngested state of the In
FER sufacs, accompanied with some pain
When it is shewn that the eye is not
equal to the work required of it the
proper remedy is not rest, for that is "a
tai to its strength. but the use Of glasses
Of sufficient power TO render unnecessa
ry sufficient effort in accommodating
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
reached their fnll devslOpement. At the
age Of 45 or so years the lenses cease t
thicken, when the pressure is removed
and their prssbyopic, or old sight begias
When child Ia compelled to use or 70
quire the use Of glasses, there is littl,
reason TO hepe that it will OutgrOw tn,
need; but the person will use three glas
ses as basis. adding other glasses al
he reaches the age when old sight be
gins or using thicker glasses. DR.. Seely
however mentioned one sase ne had Ob
served whore child had outgrOwn til,
need of glasses, but Ia the meantime b,
had grown from small and puny ehilt
to large and well developed man.
Second sight or the apparent reesver.
Of strength Of vision, which Is sometime
seen In the aged. the lecturer explain
ed as a change-an elongation-in tn
shape of. the ey0ball, by which the per
son became nearsighted, acc0mpanie
by a change in tho lsrs caused by tn
appearance of the cataract. -Scientaf
| American