reducing intra-ocular tension. Coleman quotes Le Prince's observations,
who applies the negative pole to the eye and the positive pole to the
neck, gradually passing a current of 30 to 40 ma. during a quarter of an
hour, and who reports notable diminution of tension. Coleman points out
that in his own experience he has not found any patient who would
willingly tolerate more than 19 ma. of current with an ordinary sized
electrode, although he grants that it is possible that Le Prince used a
very large electrode. Unfortunately he does not mention its size.
Ziegler of my own city, who has studied most scientifically and
intelligently the use of electricity in diseases of the eye, announces
this rule: The positive pole should be used in all inflammatory
processes of the eye, glaucoma excepted, and with this rule Coleman
agrees. Now, although the negative pole is a stimulant and therefore not
generally indicated in inflammation, as Coleman points out, the object
in view is to diminish the density of the ocular capsule and its
tension, hence the negative rather than the positive pole should be
used, inasmuch as the former, according to him, while it is a sedative,
hardens tissue and would tend to increase intra-ocular tension by
diminishing excretion. Moreover, in chronic glaucoma the ordinary
inflammatory processes are not present, indeed, primary acute glaucoma
itself is not an inflammation.
I have no personal experience in the use of the constant current with
negative pole application to the eye in the reduction of increased
intra-ocular tension, but quote for our general benefit the opinions of
those who have employed it. I have always been very frankly pessimistic
in regard to the therapeutic value of electricity in ocular disorders.
Perhaps I am wrong; I am willing to be enlightened. There seems little
doubt that Truc and Imbert's observations that high frequency currents
can temporarily reduce intra-ocular tension is correct, that they are
able to relieve the pain of primary and of secondary glaucoma would
seem to be proved by many observations, some of which I have myself
made, and other very accurate and excellent ones have been made by
Risley in Philadelphia.
A word might be said in regard to _diathermy_. According to Zahn, the
method of applying diathermy to the human eye is to take a layer of
cotton wool 1 cm. thick soaked in a 2 per cent solution of sodium
chlorid, which is applied close to the outside of the lids. On this is
put an electrode 15 cm. in size with a large indifferent electrode
applied to the back of the neck. It is not germane to the subject to
name the various ocular diseases which were treated in this manner, but
Clausnizer has made an investigation of the influence of diathermy on
intra-ocular tension. In a number of diseases, for example,
iridocyclitis, the method produced distinct rise of pressure. In one, a
patient with secondary glaucoma, prior to the diathermic application
the tension was 371/2 mm., after the passage of the current it had
fallen to 28 mm., but the next morning the tension rose to 45 mm. In a
patient with chronic glaucoma no definite alteration of tension could be
found. This observation is mentioned, not because it puts us in
possession of a valuable therapeutic measure, but largely because it is
a good example of how in this disease it is wise to investigate any
method which furnishes a hope of relief.
In a few instances endeavor has been made to reduce the intra-ocular
tension, or at least to relieve glaucomatous symptoms, by galvanism of
the cervical sympathetic, for example, by placing one electrode along
the whole length of this nerve in the neck and one on the back of the
neck on the opposite side, 15 to 20 ma. of current being used. Good
results have been reported by an observer named Allard. I confess that I
am entirely faithless in regard to any results that may be reached in
this manner. It is possible that as the positive pole is a sedative, if
there were any influence, the influence of sedation would be present,
but certainly it has over and over again been experimentally proved that
irritation of the cervical sympathetic quite rapidly produces elevation
of intra-ocular tension of 2 to 4 mm. In some experimental work the
primary elevation of intra-ocular tension was followed by a secondary
drop.
3. _Indirect reduction of increased intra-ocular tension brought about
by lowering general vascular pressure._ Much has been written in regard
to the association between increased vascular pressure and increased
intra-ocular pressure. It is not my province to analyze observations
often contradictory and not infrequently inaccurate. This much seems to
be established: First, that at corresponding ages there is usually a
higher average blood pressure in glaucomatous subjects than there is in
non-glaucomatous subjects; second, that arteriosclerosis and therefore
usually increased blood pressure, with all its concomitant conditions,
is correctly classified as an exciting cause of glaucoma; and third,
that the regulation of this increased blood pressure is part of the
advantageous management of increased intra-ocular pressure, although it
may be too much to say, as Gilbert has, that blood pressure and
intra-ocular pressure rise and fall together. It may be true, as Thomas
Henderson says, that the intra-ocular pressure is influenced by changes
in the general arterial or general venous pressures, whereby a rise in
general arterial pressure induces a proportionate rise in the
intra-ocular pressure, but it would seem that future investigations must
confirm this statement before it can be entirely accepted, as well as
his further statement that the effect of an increased general venous
pressure is a direct one, producing millimeter for millimeter a
corresponding increase in the intra-ocular pressure.
Now, it goes without saying, if these data are correct, or even only
partly correct, that part of the treatment of the increased intra-ocular
pressure state must be constitutional in that the vascular pressures
should be lowered in order that the beneficial effect of their
relationship to the intra-ocular pressure shall be established. It is
further a great mistake to drive down a high arterial pressure simply
because that exists. In other words, it is often necessary from the
general standpoint that a certain amount of plus pressure shall remain
if the patient's general well-being is to be maintained. There must
always be a differential diagnosis between plus pressure and what may be
called over plus pressure. That is to say, a man may be perfectly
comfortable and properly need, for example, a pressure of 160 or 165
mm., which is above the physiologic limit, but which is a plus pressure,
while some disturbance in his general life may add to that 10, 15 or 20
mm. more of pressure, which is then the over plus amount. This over
plus amount may be in association with a rise of intra-ocular pressure,
and must be eliminated if the latter is to be controlled by a
non-operative procedure, or, indeed, by an operative one.
It is no easy matter to determine the presence of increased venous
pressure, although there are tolerably accurate instrumental technics,
and yet, as Henderson points out, it is just this increased general
venous pressure which is often detrimental. Therefore the perfunctory
use of such drugs as nitrite of amyl and the other nitrites may not be
in the least indicated when, for example, the venous pressure depends
upon inability of the right heart to perform its functions, and the drug
needed may, for example, be digitalis. Far better than pressure-reducing
drugs like nitrite of amyl, urgently indicated in some instances and for
some purposes, is the regulation of life and the restoration to their
normality of the metabolic processes, the elimination of the worry
which is usually the exciting agent that brings about the over plus
pressure, which may have as one of its expressions an acute rise of
intra-ocular tension. I believe that in the management of a case of
glaucoma, whether it be chronic or chronic with sub-acute exacerbations,
the greatest care with the aid of an expert clinician must be exercised
to find out exactly what mean pressure of the arterial and venous system
best conforms with the patient's general welfare, and I am bitterly
opposed, and I think with right, to the sudden reduction of tensions,
except in emergencies, without a perfect understanding of the facts I
have ventured to indicate. This does not for a moment mean that prior,
for example, to operative work it is not necessary to get rid by means
of drugs of an over plus tension, for surely the elimination of such an
over plus tension may be the means of preventing, for example, an
intra-ocular hemorrhage, and in this emergency we must not lose sight
of Gilbert's recent investigation, who has found that blood withdrawn to
the extent of 8 grams to each kilogram of the body weight always
produces lowering of the intra-ocular tension, appearing in six to eight
hours and lasting to the next day in simple glaucoma, and in
inflammatory glaucoma commencing the day after the venesection and
lasting two to three days. It is not necessary for me to point out the
value of free purgation and diaphoresis in this respect.
In most instances the successful maintenance of a glaucomatous life,
exclusive of operative interference, in addition to sustained myosis,
demands the investigation of the patient's metabolism, which must be
kept at the normal standard, the removal of the evil effects of
auto-infection, as we are wont to call it, and especially the
elimination of the cause which is responsible for the over plus tension
of the arteries and of the veins. This is best secured by just such
regulation of life as has been referred to, aided when necessary by the
ordinary drugs which the patient's condition indicate, and the success
of all treatments, be they operative or non-operative, is enhanced if
such a happy state of affairs can be brought about.
I am firmly convinced that every glaucomatous patient, and I now refer
to those who are the subjects of chronic progressive glaucoma, should be
carefully studied from the general standpoint by the oculist with the
aid of an expert internist, just as I am convinced that the modern
expert internist should not study his cases of cardio-vascular disease
without the help of the oculist. Perhaps I am going a little far afield,
but in justification of my statement I want to quote the opinion of Dr.
Hobart Hare, one of America's most expert clinicians, on blood pressure,
because it seems to me much harm has been done by the more or less
brutal knocking down of blood pressure simply because blood pressure
above the normal existed. "Concerning the matter of high blood
pressure," writes Hare, "independent of cerebral lesions, the longer I
study the matter the more convinced I am that this blood pressure is
devised by nature to compensate for fibroid changes in peripheral
vessels, in order that tissues which would otherwise be cut off from
adequate blood supply may receive plenty of blood, and I consider it one
of the most vital points to ascertain whether a pressure is what may be
called the patient's pathological norm, that is, the pressure which is
required in the face of vascular changes, or whether this pressure is in
excess of his pathological norm. If it is in excess, measures directed
to bring it to the pathological norm should be instituted, but if the
pressure found proves to be the pathological norm it is a bitter mistake
to lower it, be the pressure what it may. If it is lowered below the
pathological norm, all manner of disturbed cardiac action, etc., may
result. There is no more reason for reducing a blood pressure below his
pathological norm than there is for reducing it below his physiological
norm. The adjustment of a man's blood pressure to his pathological norm
often has to be as correctly done as the adjustment of a watch which is
losing or gaining time."
I shall not quote Hare's elaborate methods for determining these various
points because they do not belong to a paper of this character, but I
quote his admirable advice because it emphasizes what I believe to be an
essential in the treatment of chronic glaucoma, exclusive of operative
work, that is, the intelligent co-operation of the oculist and the
internist.
Some such thought was in the mind of Ibershoff, who quotes Sterling and
Henderson's views that the rate of secretion depends upon and varies
with the difference in the blood pressure and the tension of the
eyeball, and that the specific gravity of the secretion increases
directly with the blood pressure and inversely with the ocular tension.
Should the blood pressure be very high, paracentesis, for example, would
apparently not be the proper procedure, and the resulting difference
produced between the blood pressure and the eye tension would cause a
rapid reformation of fluid with higher specific gravity and higher
osmotic coefficient. The proper procedure in these circumstances is
first properly to reduce the blood pressure, or what I have, quoting
Hare, ventured to call the over plus pressure.
4. _The relation of osmosis, lymphagogue activity, absorption of edema,
capillary contractility and decreased affinity of ocular colloids for
water to the reduction of increased intra-ocular tension._ We are all
familiar with the attention which was directed some years ago to the
statements coming from French clinics that the treatment of glaucoma
should include the administration of osmotic substances as adjuvants in
the reduction of increased intra-ocular tension. Particularly was this
treatment advocated by Cantonnet in the administration of daily doses of
3 grams of chlorid of sodium, preceded, of course, by a careful urinary
examination and the estimation of the amount of urine and its contained
chlorids. Carefully this dose was increased in proper circumstances to
15 grams per diem, and in Cantonnet's original paper good results were
achieved in 12 of the 17 patients so treated. I have myself experimented
somewhat, not with the administration of sodium chlorid by the mouth,
but with the introduction by the bowel of fairly large quantities of
physiologic salt solution in patients with glaucoma whose quantity of
urinary secretion was markedly below the normal, and in one or two
startling instances, which have been reported, achieved success in the
rapid reduction of the intra-ocular tension when by this technic the
urine secretion rose to the normal amount. To be sure, myotics were
also used, but these myotics were insufficient, totally so in the two
instances noted prior to the enteroclysis.
Very interesting are the observations on the subconjunctival injections
of various substances, notably the citrate of sodium, because of its
power of decreasing the affinity of ocular colloids for water. This
method of treating increased intra-ocular tension, introduced, as you
know, by Thomas and Fischer, has met with confirmation from a number of
sources in spite of the fact that Happe's experimental study failed to
confirm Fischer's observations; indeed, he even reports in several
instances a rise of tension.
As you will remember, the strength of ordinary crystallized sodium
citrate in water should be from 4.05 to 5.41 per cent. Of this five to
fifteen minims are injected, the eye having been previously cocainized
and adrenalinized. With frequent injections the weaker of the two
solutions is mixed with 2 to 4 parts of physiologic salt solution. These
authors in no sense claim to cure glaucoma, but to ameloriate it and
reduce the tension. Weekers has used the salts of calcium, 3 grams a
day, with success in so far as lowering of tension is concerned,
although it must be stated, as a reviewer of his work has said, that his
recommendation of this drug in these respects is poorly supported. On
the other hand, Tristiano seems to have proved that calcium chlorid is
capable of lowering ocular tension and clinically may be used as an
adjuvant in the treatment of glaucoma for this purpose, largely because
he believes that he has proven that it facilitates the absorption of
edema. Darier has reported that a single subconjunctival injection of a
milligram of iodate of sodium has cleared the cornea and lessened the
intra-ocular pain in glaucoma.
What shall be said in regard to certain medicinal agents which stimulate
the lymphagogue activity of the eyeball in their relation to the
reduction of intra-ocular tension, notably of dionin? Toczyski's
experiments with this drug on the normal eye indicate that it produces
first a rise of tension, which shortly falls to the normal and sometimes
below it, the tension being high as long as the primary narrowing of the
pupil is maintained, but more than one author, particularly A. Senn,
holds an opposite view and reports acute glaucoma following its
instillation into a chronic glaucomatous eye. He believes that dionin
not only does not reduce the tension but hinders the filtration through
the anterior lymph channels by the pressure of the edema which is
produced on the veins and by the increased secretion of the ciliary
processes. In spite of this statement, most of us must agree with Karl
Grossman's observations that certainly in acute and particularly in
chronic secondary glaucoma, this is a most valuable agent, especially if
it is combined with holocain, which Paul Knapp in his well-known
research has proved can reduce the tension even of the normal eye. I
cannot think that anybody who has systematically used dionin with
holocain, the former in gradually increasing strength, beginning with 2
per cent and going up to 8 per cent, in various types of acute glaucoma,
particularly of the secondary variety, can fail to have noted a
favorable influence.
Many authors, for example, Darier, Grandclement and others, are strong
in their recommendation of adrenalin, particularly if this drug is added
to the various myotic mixtures, and yet adrenalin is certainly not
without danger in the treatment of glaucoma. McCallan has seen a number
of instances of striking increase of intra-ocular tension following this
instillation in the conjunctival sac. Harmon has had a similar
experience, as also has Senn. It is possible that in these circumstances
the solution was too strong. Should the rise of tension occur, and I
have seen it myself, it is doubtless due to the fact that this drug
dilates the pupil, which would be especially dangerous if the dilatation
should occur before contraction of the ciliary vessels; also the
narrowing of the ciliary veins by the adrenalin might by virtue of this
narrowing obstruct the gate of outflow. I have never been able to
persuade myself that, except as an adjuvant to operative work, there was
any real therapeutic value in the instillation of adrenalin.
A word in regard to the effect of general narcosis on intra-ocular
tension. Thus, Neuschuler has observed that narcosis causes an elevation
of the intra-ocular tension of from 2 to 6 degrees as measured with
Fick's tonometer. These observations were made while he was
experimenting on irritation of the sympathetic as a method of producing
increased intra-ocular tension. This is not in accord with Axenfeld's
recent observations. It is well known, this observer points out, that
after the period of excitation and muscular rigidity disappears, there
is a lowering of blood pressure in chloroform narcosis and coincidently
a sinking of the intra-ocular pressure. Not only this, the intra-ocular
tension of normal eyes during this narcosis drops several millimeters.
Only such eyes as have high hypertony, for example, in absolute
glaucoma, are unaffected during chloroform narcosis. In the light of
this observation it will be interesting to measure the tension both of
normal and glaucomatous eyes during narcosis in a large series of cases,
and if it is confirmed there will be an additional reason why in many
circumstances general narcosis is advantageous in glaucomatous patients.
Formerly I thought it was essential, if iridectomy was to be performed,
lest some sudden movement on the part of the patient might bring the
point of the knife in contact with the lens. I have rarely employed it
in corneo-scleral trephining, and yet if there is this temporary
reduction of intra-ocular pressure, it is not without a certain
therapeutic value, and the matter is mentioned as a suggestion that
additional observations along this line shall be made.
Dr. George Edmund de Schweinitz' Paper on Concerning Non-Surgical
Measures for the Reduction of Increased Intra-ocular Tension
Discussion,
NELSON MILES BLACK, M.D.,
Milwaukee.
It seems almost useless to attempt any discussion of Dr. de Schweinitz'
most terse and comprehensive paper. However, Dr. de Schweinitz mentioned
the close relationship which should exist in the non-surgical treatment
of increased intra-ocular tension between the internist and the
ophthalmologist, but neglected to mention a corresponding relation which
should exist between the rhinologist and the ophthalmologist, and
possibly between the dental surgeon and the ophthalmologist.
I would like to refer to the _now_ recognized close relationship which
exists between disease of the nasal accessory sinuses and diseases of
the eye. The definition of glaucoma found in Dr. Wood's system of
therapeutics gives rise to an hypothesis as to why disease of the nasal
accessory sinuses may be a factor in producing increased intra-ocular
tension and why treatment directed toward obtaining free drainage from
the sinuses gives good results in so many cases, especially if the
relationship is recognized sufficiently early. "Glaucoma proper is
essentially a damming or blocking of the drainage from the interior of
the eye. The chief lymph stream flows from the posterior chamber past
the margin of the lens, through the zonula of Zinn, beneath the iris,
through the pupil into the anterior chamber, thence through the tissue
at the junction of the iris and sclera into the circular canal of
Schlemm and from this space into _the external lymph channels_.
_Obstruction to the steady escape of the intra-ocular fluids at any
point in this drainage system or any undue increase of the fluids
themselves may produce glaucoma._ Probably the most important
obstruction to the exosmosis is at the angle close to Schlemm's canal."
The following hypothesis is based upon Fischer's edema theory of
glaucoma and the relation of the circulation of the eye and orbit and
that of the nose and the accessory sinuses, the minute anatomy of which
is not as yet thoroughly understood. However, sufficient work has been
done to make it appear that the lymph channels which drain the eyes and
orbits empty into the same main channel as do those which drain the
sinuses. Admitted for sake of argument that such is the case, then
disease either acute or chronic of one or more of the sinuses with the
accompanying inflammatory reaction, congestion and stasis, will cause an
increased amount of fluid to be taken care of by the lymph channels
draining these sinuses. This will in turn cause flooding of the common
lymph channel, producing a stagnation in the flow of fluid from the
orbits and eyes at the junction with the main channel, with backing up
of the fluid within these channels and retention of the waste products
within the orbits and eyes; thus will be brought about conditions most
favorable (to quote from Fischer's theory of glaucoma) "to an abnormal
production or accumulation of acid in the eye. In consequence of this
abnormal acid content the hydration capacity of the ocular colloids is
raised and glaucoma results, not because water is pushed into the ocular
colloids, but because these suffer changes which make them suck in water
from any available source."
This hypothesis also might suggest why the subconjunctival injection of
sodium citrate in addition to alkalinizing the ocular contents, may be
effective in reducing tension, _i. e._, the amount of fluid injected
beneath conjunctiva may overcome the stagnation in the lymph passages,
flush out these channels and improve ocular elimination.
Fischer in a personal letter says:
"You have two possibilities for the production of glaucoma with sinus
disease: A toxic factor due to poisons being carried into the eye; and
second, interference with a proper blood supply to the eye through
compression of the efferent or afferent blood vessels supplying the eye
from edema of the tissues about the eye consequent upon the sinus
infection. Either is associated with the production of substances which
increase the hydration capacity of the ocular colloids."