The Eye in its Relation to Health
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By Chalmer Prentice, M.D.
Chicago, A.C. McClurg & Company, 1895
Transcription (c) A. Wik, 2004

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        | Chapter VI |  pages 68-78
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								68

EACH eye has seven muscles which perform all
the movements necessary in the functions of
vision.  Four of them are called recti or straight
muscles, as follows: the superior rectus muscle

	[illustration]

turns the eye upward, the inferior downward, the
external outward, the internal inward or toward
the nose; two are called the superior oblique and
the inferior oblique, the offices of which are to
rotate the eye on its antero-posterior axis.  The
seventh is the ciliary muscle which is within the
eye-ball and surrounds the crystalline lens.  Some
of the above mentioned muscles are assisted in
the performance of their functions by other mus-
cles.  This is explained at length farther on.

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  When we think of the complex arrangement
of these muscles in the two eyes, we must know
that for the easiest possible vision, it is necessary
that they should be absolutely perfect as to length
and their attachments; also that the crystalline
lens should be anatomically correct.  Here we
have in the two eyes, sixteen anatomical parts
that must be without fault.  This naturally leads us
to infer that the perfect eye is an exception, and a
wide experience has taught us that irregularities in
in some of these parts are very common.  It would
be marvelous if one pair of eyes in a hundred were
absolutely balanced without the intervention of
nerve-impulse to overcome some slight defect.
These muscles are often so imperfect in length and
irregular in their attachments, as to cause the eyes
to deviate many degrees from the normal position.
When the axes of vision deviate so far that it is
impossible for the nerve-impulses to pull them
back into line, we have a condition commonly
known as strabismus or squint.  The deviation
may be outward, inward, upward, downward, or a
combination of two of these directions.  When
the angle of deviation is so great that it cannot
be corrected by the nerve-impulses that operate
these muscles, the effort to produce single vision
becomes more or less suspended and the laborious
work of the nerve-centers is abandoned.  Usually
one of the eyes suppresses its vision; for, as long

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as double vision of the same object exists, there
will always be an effort to fuse the two images
into one for the sake of avoiding confusion and
increasing the sense of sight.
  Defects in various parts of the eye, including
the muscles as to their length, may exist to a
very considerable extent and yet the function of
vision be perfectly performed.  Some of the mus-
cles may be so short that they would cause the
optic axes of the two eyes to deviate many
degrees if it were not that the opposite muscles
pull them into a normal position, through the
intervention of nerve-impulse.  Nerve-impulse is
also the primary factor in causing the ciliary mus-
cle to contract around the crystalline lens, increas-
ing its refractive power when it is deficient.  Just
how fixed and permanent, through a long lapse of
time, these nerve-impulses may become, acting as
masks to anatomical defects, is the object of our
chief inquiry.
  Eyes that perfectly perform the function of
vision may have hidden defects to an alarming
extent and in proportion far greater than the
novice would expect.  Some little evidence in
this direction can be had from the following:  I
do not believe that full suspension of abnormal
innervation takes place in blind eyes, but suspen-
sion does to a certain extent.  Through a period
of many years, I have been observing the eyes

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of the blind with the especial purpose of noting
their relative positions, and I cannot recall one
individual case in which the optic axes had not
deviated in some direction.
  A similar condition of affairs exists in the
eyes of a new born babe.  One or more mus-
cles may be defective as to length.  Whoever
has watched the eyes of these little ones has
noted how aimlessly they wander about during
the first few days, until finally the stimulus for
fusion causes them to fix their vision; and then
for the first time, the two eyes begin to look in
the same direction and so continue.
  "The eyes of new born infants are almost in-
variably hypermetropic." (Berry.)  This being
true, it is the long continued effort of the ciliary
muscle that brings about the emmetropia of later
life, which is so firmly fixed, that even mydriat-
ics sometimes fail to discover latent hyperopia.
  In fourteen autopsies, not one exception was
found to the unequal development of long mus-
cles.  In eleven of these cases, the superior
rectus in the right or left eye was thin, tendonous
and undeveloped, giving evidence of having been
on the stretch, while that of the other eye was
invariably a well developed muscle, and the con-
verse condition of the inferior muscle was always
found.  In two of these eleven, the external
muscles were undeveloped, while the internal

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showed a high state of muscular development.
In one of the remaining three, a habitual drunkard
and suicide, the internal muscles were thin and
tendonous, the externals being highly developed;
in the other two, the externals were simply thin,
attenuated tendons, the internals being highly
developed.  The superior and inferior muscles in
the last three cases were so poorly developed
that they gave no evidence of any relative dif-
ference.  A more general inquiry and a larger
experience than I have had the fortune to
acquire in examining the ocular muscles and the
positions of the eyes of the dead, will bring out
much valuable evidence in this field which as yet
is comparatively new.
  Look into the dim windows of the brain
twenty-four hours after death, and a deviation of
the eyes from a perfect position will always be
found.  This evidence is also against the theory
of muscular weakness or paresis as a general
cause for the deviation of the eyes, for in death
no innervation exists, and no relative strength or
weakness.  They naturally fall into the positions
that the relative lengths permit them to assume.
Even then the full defects do not become mani-
fest, for the long stretched muscle will yet be too
long; but all this information comes too late for
the life which is ended.  Too late for aught
but an apology for perhaps many a cen-

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sured weakness, which, after all, was no more
than the manifestation of some physical infirmity
for which the victim was morally blameless.
Under infirmities thus insidiously induced, but as
restless as the lightning, a Dr. Jekyll becomes
a Mr. Hyde.  Let us judge justly of the infirmi-
ties of man or judge them not at all.  THE TEN-
DENCY OF A PERFECT BRAIN IS TO A PERFECT
BODY AND A PERFECT LIFE.  The perfect devel-
opments of a brain or any part may be pre-
vented by the existence of some irritant cause.
People with disagreeable dispositions and habits
are not always responsible, as their peculiar-
ities are possibly the result of abnormal nerve-
impulses over which they have no control; and
such people should excite our kindliest feelings
rather than our condemnation.
  Several years ago I was called from a great
distance to see a patient suffering from what was
at times a severe craving for alcoholic stimulus.
During this period excessive amounts of liquor
were drunk, the debauch continuing about one
month.  His dissipation was as deep as possible.
After this followed the period of sobering.  Then
for three or four months he would again lead a per-
fectly abstemious life.  He was notably kind and
generous to the poor; lent great aid to moral
institutions; was a kind, good father and husband,
and seriously devoted to the church.  It was at

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the conclusion of one of his sprees that I reached
his home too late to see him alive.  On the fol-
lowing day, the thought came to me that if
eye-strain had had any connection with his
infirmity, it perhaps might manifest itself after
death; so, in the company of his old partner
and friend, and two undertakers, I carefully
raised his eyelids.  The left was fixed in a nor-
mal position, the right was turned upward fully
twenty-two degrees.  Such evidence ought to
be a sufficient explanation and vindication of
many acts that may have incurred censure during
life.
  The average person of middle age whose eyes
are apparently perfect, may be seated behind an
8 deg. prism, base down, when at twenty feet a
light will appear as two lights, one directly over
the other or vertical.  According to the prevail-
ing idea, this indicates that the eyes are balanced
as far as the lateral or external and internal
rectus muscles are concerned.  Now, if this bal-
ance depends upon the anatomical length of the
muscles, the following test would indicate it; but
it does not.  I place on the patient in trial frames,
say 6 deg. of prism, base out; I direct the patient
to look around the room for a few minutes; I
now renew my test with the 8 deg. prism, base
down, while the 6 deg. prism is still on the
patient.  One of the two lights still appears to be

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directly over the other.  We are now certain that
we have 6 deg. of prism unaccounted for by the
test.  Sometimes we are able to put as high as
twenty or even more degrees of prism over the
person's eyes, base in or out, as just described,
and after they have been used for an hours, more
or less, the two dots or lights in the test will
still appear to be vertical.  If it had been only
the length of the muscles with which we were
dealing, and the lateral muscles balanced with-
out prisms, when we put on 6 deg. of prism, base
in or base out, we ought to have found the dif-
ference in length by the irregularity in the
position of the lights; but in such cases the dif-
ference does not appear in this way, and such
experiments clearly demonstrate how uncertain
all diffusion tests are.  Long trained, and more
or less fixed abnormal nerve-impulses will hide
defects from these tests that would otherwise
cause the eyes to deviate many degrees.
  Now, if this tendency to single vision asserts
itself with such alacrity and certainty under an
artificially created irregularity, how much more
would the constant effort of years of working and
pulling against a muscle that is too short, have a
tendency to hide the defect from all diffusion
tests?
  The various disturbances taking their origin in
the visual nerve-centers from eye-strain, have

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been doing their devastating work, have been gen-
erating from the very time of birth, from the
very hour the two eyes first began to train together,
those conditions that are conductive to disease.
From that moment, nerve-force waste and brain
irritation with its correlated consequences began.
It is true, in certain cases, that some of the most
distressing symptoms of disease are often relieved
immediately on a correction of the abnormal
innervation; but it stands to reason that the
greater portion of disturbed conditions, which
have been so many years in assuming definite
form, will require patience and time for perfect
relief.  A new established order of things must
be set up.  The various nerve-impulses that per-
form their characteristic functions must all be
changed.  The centers that generate this force
and the avenues they travel, must all be differen-
tiated.  A new correlation has to be established,
and sufficiently long established to maintain a
permanency of the new and desired condition of
affairs.  If in six months, a year or more, the
impulses from the nerve-centers have become so
altered as to turn aside some disease where death
was imminent, we can well say that the patient
and the physician have been well rewarded and
that the time was short, although the patience of
both has been severely taxed.
  The immediate relief of pain that sometimes

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follows the application of glasses or operations,
must not be considered infallible indications
of a speedy cure.  Such a relief is simply an
indication that we are proceeding in the right
direction; and, although a pain may be stopped,
or a prominent and alarming symptom subju-
gated, before perfect health is restored there are
other fully as important changes to take place
which will require a space of months and perhaps
years.  Often serious diseases or conditions exist
that are accompanied by no prominent symptoms
of pain; nevertheless they are as emphatically
threatening to life.  Where disturbed brain centers
have been for years furnishing imperfect motive-
force to perform the various functions through-
out the body, the functions become more or less
enfeebled.  Their structural assimilation has been
imperfect.  In such a case, when pain is relieved
by a change which we have wrought in the
nerve-centers, we must expect to wait some time
for the permanent establishment of those motive-
impulses that normally control assimilation and
organic functions.  It takes time to rebuild that
which has been many years in breaking down.
We are apt to become enthusiastic when sud-
denly relieved of some pain or alarming symp-
tom; but the process of reconstruction that fol-
lows the new supply of vital force is a slow one;
we are not conscious of it from day to day; we

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can realize it only after a much longer lapse of
time.  If these changes are carefully noted
through periods of several months, more or less,
we can become calmly conscious that years will
be slowly added to life.  The good that follows
repression may possibly keep on building up and
restoring for a space of years.  The sustaining
power of repression is well established in such
cases as Nos. 5, 16 and 17, pages 95, 113 and
114.
  In the slow development of latent eye defects,
we learn how obstinate and unyielding long es-
tablished abnormal nerve-impulses are, how they
repeatedly persist in their endeavor to return
during development after we have held them
more or less repressed for several months.  We
have a correspondingly new state of affairs estab-
lished, a changed condition of innervation which
is young, and more or less uncertain.  We
may be somewhat prepared to expect at times a
temporary return of the old impulses, especially
when the nerve-centers have been subjected to
exhaustion, or when their equilibrium is disturbed
by alcoholic stimulus, or by an exhausting
debauch in any direction.  Under such condi-
tions the new ocular correlation will become tem-
porarily confused, which plainly indicates a need
of rest, but after a time this confused state ceases
to present itself.






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        | End of Chapter VI |  pages 68-78
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