turbid by transudation of serum from the vessel of the ciliary body and
the chorioid and may become filled with fibrin. In some chronic cases
in which absolute glaucoma is reached the development of small blood
vessels in convoluted loops springing from the vessels of the discs has
been observed. Any process that increases the volume of the contents of
the vitreous chamber, as hemorrhage, neoplasm, profuse serous or plastic
exudation, may by pushing iris and lens forward produce an attack of
acute glaucoma.
_Buphthalmos._ Reis (Graefe's Arch. f. Ophth. V. LX. 1905) states that
there is always obliteration of the anterior scleral venous channels
(Schlemm's canal) in buphthalmos. Seefelder (Graefe's Arch. V. LXIII.
1906) mentions the abnormal position and abnormal narrowing of Schlemm's
canal and the imperfect and insufficient differentiation of the
cornea-scleral junction. In all of the cases in which the eye has been
examined microscopically obliteration of Schlemm's canal has been
reported. This is thought to be a defect in development. Magitot (Ann.
d'Oculis CXLVII) suggests that injury to mesoderm which pushes itself
between the ectoderm and anterior surface of the lens would account for
the failure in development of Schlemm's canal. The changes that occur in
the tissues of the eye appear to be largely due to the stretching
consequent on the more or less uniform distentions of the globe as a
result of hypertension.
_Cornea._ This portion of the fibrous membrane is enlarged, globous or
flattened, irregularly thinned, particularly at the periphery, where it
may be as thin as tissue paper, nebulous because of the stretching of
its fibers principally, but in some degree (differing in different
cases) to edema of the epithelial layer. Fissures occur in Descemet's
membrane.
_Anterior Chamber._ This is very deep in the greater number of cases.
However, this rule has many exceptions.
The vascular tunic may be congested in young infants, but atrophy soon
develops and may reach an extreme degree. The sclera ordinarily becomes
quite thin throughout, but may retain almost a normal thickness at the
equator of the globe and posteriorly. Posterior sclera ectasae may
develop. The iris, as a rule, hangs free from the cornea, often
tremulous because of retraction of the lens beyond the iris plane. In
some cases the iris is partly or totally adherent to the posterior
surface of the cornea.
The vascular membrane (iris, ciliary body and chorioid) and the retina
become atrophic, the atrophy varying in degree in various parts.
Detachment of the retina may occur, often preceded by or accompanied by
subretinal hemorrhage. The optic disc becomes deeply cupped and the
tissues of the optic disc and optic nerve extremely atrophied. The
crystalline lens may become cataractous and shrunken. Spontaneous
rupture of the suspensory ligament with consequent subluxation of the
lens may follow.
_Secondary Glaucoma._ The pathological conditions that precede
secondary glaucoma are many and differ widely. They may be briefly
classified as:
1. Those that cause a partial or complete closure of the lymph spaces
and Schlemm's canal by cicatrical contraction, as in sclero-keratitis.
2. Those that cause obstruction to the lymph spaces at the filtration
angle by the deposition of fibrin or cellular elements, as in iritis,
hemorrhage into the anterior chamber, etc.
3. Those that cause obstruction of the filtration angle by advancement
of the iris and lens, as occurs when the volume of the contents of the
vitreous chamber is increased, as from retinal or chorioidal hemorrhage
or neoplasm.
The various changes are so numerous that they need not be described
further here. The ultimate changes due to high tension resemble those
already described.
Dr. John E. Weeks' Paper on Pathology of Glaucoma
Discussion,
E. V. L. BROWN, M.D.,
Chicago.
I would like to emphasize one of the newer features of the pathologic
anatomy of glaucoma, one which has received too little attention in this
country: the _lacunar_ or _cavernous atrophy_ of the _optic nerve_.
The name accurately describes the condition. Tiny clear spaces form in
the lamina cribrosa and in front and behind it in the nerve tissue.
Their exact nature is unknown. Usually they are entirely empty, often
they are traversed by fine glial fibers. They seem to be in no relation
to the blood vessels. Adjoining lacunae are supposed to fuse to form
larger cavernae and these finally merge and constitute the final
glaucoma cup. The lamina may then bridge across the space like a cord,
or lie back against the end of the nerve trunk.
Schnabel considered all glaucoma cups to be formed in this way,
independent of tension. His views were strongly supported by Elschnig,
but as vigorously opposed by others. Axenfeld cites the fact that the
glaucoma cup may disappear after operation. (I myself have seen a cup of
7 D. reduced to 1 D. in the course of a year after the tension had been
lowered from 62 to 12.) Stock found the same lacunae in eight cases of
myopia. The last extended study of the subject was made by E. v. Hippel,
who found lacunae in 20 of 33 cases (60 per cent); enough certainly to
make one look for them carefully in every case. He publishes a large
number of excellent photo-micrographs, but none more typical than one I
have in my possession.
I have been especially interested in this subject because I have met
with a complete and total glaucoma cup, with the typical (ampulliform)
undermining of the scleral ring, in a pair of eyes without increased
tension. The (Schiotz) tonometer was used daily for 70 consecutive days
and never registered more than 12-14 mm. Hg. The man had been blinded by
wood alcohol. At the time I could find no other report in the
literature, but overlooked a publication by Lewin and Guillery.
Friedenberg has since reported cases of the same nature.
If other conditions than increased tension can produce a typical
(ampulliform) glaucomatous excavation of the disc, why may not the
cavernous atrophy and cup in glaucoma be due in part at least to similar
processes, possibly in the nature of a toxic oedema of the nerve, either
in association with tension or independent of it, as contended for by
Schnabel?
Concerning Non-Surgical Measures for the Reduction of Increased
Intra-ocular Tension
BY
GEORGE EDMUND DE SCHWEINITZ, M.D.,
Philadelphia.
Only a few years ago the literature of glaucoma was big with discussions
of the comparative value of the surgical and non-surgical treatment of
glaucoma, and especially of the chronic types of this disease. Now,
thanks to the achievements of Lagrange, Fergus, Herbert and Elliot, the
value of a filtering cicatrix, although known for a long time, has
attained increased importance, due to the improvement and elaboration of
operative technic, and the medical journals of the day are weighted with
opinions and experiences from all over the world as to these surgical
measures. But true as this is, we are not yet in a position to discard
non-surgical procedures (1) because operation is not always possible,
(2) because operation is not always permitted, and (3) because in
certain circumstances operation is not advisable. Hence a glance at the
non-surgical methods of reducing increased intra-ocular tension is not
out of place, and for convenience they may be catalogued as follows:
1. Myosis produced by means of solutions of various drugs, a myosis
followed by reduction of intra-ocular tension.
2. Reduction of tension by means of various mechanical measures, notably
massage, vibration massage and suction massage, and by means of
electricity and diathermy.
3. Indirect reduction of intra-ocular tension, accomplished by lowering
general vascular pressure.
4. Reduction of ocular tension by stimulation of osmosis, of lymphagog
activity, of absorption of edema, and of capillary contractility, and by
decreasing affinity of ocular colloids for water.
1. _The Myotics._ Of these, eserin (physostigmin) and pilocarpin, with
their respective salts, the sulphate and the salicylate in the first
instance, and the hydrochlorid and the nitrate in the second, are well
established in favor and efficiency. Personally, it has always seemed to
me that the salicylate of eserin is preferable to the sulphate, but I
have not persuaded myself that the nitrate of pilocarpin possesses
material advantages over the hydrochlorid, although some authors prefer
it. With arecalin, the alkaloid of the Betel nut, I have no experience,
nor have I used its mixture with eserin, recommended by Merck as more
potent than either of the drugs in separate solution.
The substance isophysostigmin, found with eserin in Calabar bean,
according to Ogiu, exceeds in its myotic activity the sulphate of
eserin, _i. e._, 1/80 of a grain of the drug is equal to 1/60 of a grain
of the sulphate of eserin, but it is certainly not less irritating than
physostigmin, and according to Stephenson's researches, is more so, and
in this sense has no superiority over the usual alkaloid. In general
terms, it may be said that the time has not arrived to make a preachment
"on the passing of eserin and pilocarpin."
_Physiologic Action._ Concerning the ocular, physiologic action of the
two chief alkaloids respectively of Calabar Bean and of Jaborandi, there
still exists difference of opinion. It has always been easy to attribute
the myotic action of these drugs, or at least, of eserin, to their
stimulant action on the peripheral ends of the oculo-motor, thus causing
sphincter contraction, and to a depressing action on the sympathetic
fibers, thus causing removal of the action of the dilatator of the iris.
But complete experimental proof of such action is wanting, and it is
probable that myosis follows a direct stimulation of the sphincter
muscle fibers, aided, perhaps, by contraction of the iris vessels,
although the last named effect is denied by so competent an authority as
Hobart Hare.
Exactly how the myotics reduce intra-ocular tension is not definitely
proven. Usually it is taught that because of the myosis the base of the
iris wedged in the angle of the anterior chamber is loosened and
withdrawn, precisely as a fold in a coat is straightened by a tug on the
fabric beneath it. Experiments, however, for example, by E. E.
Henderson, have shown that the rate of filtration in an eye with
artificially raised pressure is considerably larger when it is under the
influence of eserin than it is when under the influence of atropin; that
is by the contraction of the pupil the iris-surface filtration is
increased and consequently the pressure is reduced. We all know that
Thomas Henderson maintains that the results of iridectomy are beneficial
because the raw edges of the coloboma, which do not cicatrize, permit
access of the aqueous to the iris veins, and that myotics, inasmuch as
they contract the pupil, open the iris crypts and therefore act, less
efficiently, perhaps, but act none the less like an iridectomy. The
normal intra-ocular pressure is uninfluenced by myotics because this
pressure represents the lowest circulatory pressure in the eye, and
further contact between aqueous and veins cannot reduce it below this
level, another point which is made by Thomas Henderson in support of his
contention.
The clinical fact remains that either by mechanical means, as it were,
in the liberation of a plugged filtering angle, or by the increasing of
iris-surface filtration, the myotics markedly reduce the abnormal
intra-ocular pressure.
_Methods of Administration and Indications._ With the methods of
administration of the myotics we are all so familiar that time need not
be wasted in their reiteration, except to refer to a few practical
points. In acute glaucoma, and every one knows that in this disease
their action is often prompt and sometimes curative, eserin in a
strength of one to four grains to the ounce may be instilled with
sufficient frequency to establish myosis, and its action in this respect
is enhanced if the congestion of the eye is lowered by measures to which
I shall refer later. There is a good deal of clinical evidence to
indicate that in this type of glaucoma, as well as in the so-called
sub-acute varieties, myotic activity is increased by a mixture of
pilocarpin and eserin in the same solution, exactly as a mixture of
arecalin and eserin is more potent than either of the drugs in separate
solution.
Prior to the happy advent of technically correctly placed filtering
cicatrices, a large number of surgeons depended almost exclusively on
the use of myotics in so-called simple, chronic or non-inflammatory
glaucoma. This is not the place to introduce a discussion of the
comparative value of iridectomy and myotic treatment in simple glaucoma
as based upon statistical records. We must wait now for a sufficient
period of time and then compare the value of myotic treatment with that
of operations by means of which satisfactory filtration is produced. We
are somewhat in the position that general surgeons occupied when aseptic
methods first became prevalent. We do not usually compare the statistics
of early aseptic days with those of the pre-antiseptic period, and I do
not think we ought to compare the statistics of myotic treatment with
ordinary iridectomy any longer, but that we should wait until we can
make a comparison between the results of prolonged myosis and those of
an improved modern technic which establishes a permanent filtration. In
the meantime the patients who will not or cannot submit to operation
must be reckoned with. Doubtless many patients with chronic glaucoma can
be satisfactorily managed with myotic treatment, although personally I
have always advocated operation when this could be performed, but it
cannot always be performed. This rule should guide us, namely, to begin
with a comparatively weak solution of the selected drug, for example, as
Posey has advocated a tenth of a grain of salicylate of eserin to the
ounce, and the strength gradually increased so that at the end of some
months the patient is using a solution 1 grain to the ounce; or if the
pilocarpin is preferred, solutions in double these strengths. It is my
own belief, and that of many who have studied this subject, that if,
without eserin irritation, a myosis can be maintained, and if the
treatment can be begun early enough, the chances of preserving vision
and the field of vision are good. I believe that the two most important
instillations during the twenty-four hours of the number necessary to
maintain this myosis are on retiring and if possible in the very early
morning, some time between two and four o'clock. Most patients can be
taught to wake themselves at the proper period of time, and are little
inconvenienced by this disturbance of their sleep. I believe that eserin
irritation is most successfully avoided, not by preparations of the
myotics in combination with the antiseptics, for example, tricresol,
which has been so much advocated, but by ordering very small quantities
of the solution, insisting that it shall be frequently renewed and
sterilized at each preparation, and that a half an hour after its
instillation, during the day time at least, the eye shall be thoroughly
flushed with some mild antiseptic solution, for example, boric acid and
sodium chlorid. Whether the action of the eserin on the choroidal
circulation, which is maintained by Wahlfours, aids in this favorable
action of the myotics remains to be proved. It has been maintained by
this author and by others who have followed him.
The great trouble with myotic treatment is not its lack of efficiency,
but the difficulty of carrying it out successfully on ambulant
patients, even in the better walks of life. It is hard successfully to
maintain in a patient with chronic glaucoma what I may call an eserin
life, just as it is hard to maintain in a person with an enlarged
prostate a catheter life and escape infection, resulting, if it occurs,
in the one instance in a difficult and stubborn conjunctivitis, and in
the other in a cystitis. Still, we are obliged to use myotics, and the
way to employ them to the patients' best advantage, I have ventured to
repeat in spite of the universal familiarity with the methods. Perhaps
we may reach that happy day when, especially with improved tonometric
methods, increased skill in measuring the rate of filtration and better
instruments for determining the light sense, we can anticipate the
advent of glaucoma and get ahead of the ocular and visual deterioration
which increased tension produces, by performing preventive operations
which shall aid nature's filtration channels in the establishment of an
artificial one. But increased tension is not the whole story of
glaucoma, and a filtering cicatrix is not the last word in surgical
therapeutics, and there is much to learn.
2. _Reduction of tension by means of various mechanical measures,
notably massage, and by means of electricity and diathermy._ Massage is
of ancient lineage. In general terms, in so far as ocular massage is
concerned, it may be applied to the eye with the finger tips (ordinary
massage), by means of various instruments (vibration massage), and with
the help of certain suction cups (suction massage, which is indeed a
form of vibratory massage). Many authors are satisfied with their
results without the employment of any instrument, and prefer simple
massage with the tip of the finger to any form of the instrumental
variety, to quote the words of Casey Wood. At one time in my career I
experimented very extensively with massage, not alone for the purpose
of reducing intra-ocular tension, but in various diseases of the lid and
cornea, and taught a trained nurse, who herself had a nebulous cornea,
to make what I may call a specialty of this particular therapeutic
procedure. She became exceedingly skillful and was quite faithful. We
believed that the best results were obtained in a seance of two or three
minutes, the finger tip being used over the lid, and the surface of the
cornea lubricated with a drop of pure olive oil, although in glaucoma
the addition of the oil is not necessary. Four movements were utilized,
the first a stroking movement in lines radiating from the central
pressure, very much as the spokes of a wheel radiate from the hub,
second a circular movement, third a pressure movement, a little dipping
motion, so that the cornea was slightly depressed, and finally, a gentle
tapping movement, precisely the same, except that it was a diminutive
one, as the tapping movement that the Swedish masseur makes. Usually
each movement occupied from a half to one minute, according to the
results desired. I agree with Casey Wood that such a technic furnishes
just as good results as any one with the aid of an instrument.
Referring particularly to the reduction of intra-ocular tension, many
surgeons have been impressed with the value of various instruments.
Thus, Ohm, who has worked particularly in the reduction of the increased
tension of secondary glaucoma, for example, after discussion of lamellar
cataract, advocates the Piesbergen instrument, which makes 3,000
vibrations a minute, and is applied over the closed lids. I think the
instrument best known is the one introduced by Malakow. For this purpose
the point of an Edison electric pen is armed with a small ivory ball,
and the vibration rate varies from 200 to several thousand a minute, the
rapidly revolving ball being passed over the closed lids, in some
instances directly upon the cornea itself. I am frankly afraid of these
vibrating machines, and again make a plea for the finger tip, just as I
am afraid of a Von Hippel trephine, and prefer one which is rotated with
the fingers.
A special investigation of pressure massage according to the method of
Domec has been made by Paul Knapp of Basel. This, as you know, consists
in applying the thumb to the cornea through the closed lids, and making
repeated pressures upon it at the rate or 60 to 100 a minute. He checked
his results with the tonometer after 200, 500 and 1,000 pressures, and
found that even in normal eyeballs such massage was followed by a fall
of intra-ocular tension, the average being nearly 9 mm. after a thousand
pressures. Within three-quarters of an hour the tension returns to the
normal. In acute glaucoma such massage is not available, but it is of
assistance in encouraging a reduction of the intra-ocular tension and
keeping it at a normal grade after operative work, particularly after a
filtering cicatrix has been made, as was well shown by Weeks in his
study of glaucomatous eyes operated upon by the Lagrange method. It is
interesting to remember that Paul Knapp, in the course of this
investigation, observed reduction of the tension after the use of
holocain.
Another method of reducing the intra-ocular tension is by the suction
method, which consists in the use of certain cups from which the air is
exhausted by means of a suction apparatus. Domec uses an elliptical eye
cup, the concave margins of which fit closely about the globe. The air
is exhausted with each respiration of the patient and from 50 to 200
tractions are made at each sitting. Domec is of the opinion that this
method succeeds in two ways, namely, in producing analgesia by traction
on the ciliary nerves, and in reducing intra-ocular tension.
Unfortunately, it is difficult for regular physicians to make reference
to massage of the eyeball lest their words should be misquoted by
irregular practitioners who employ this method, selling various
instruments to trusting patients, and attributing to this simple and
often beneficial procedure all sorts of marvelous influences. Doubtless
all of us have seen eyes utterly ruined because the patient has trusted
to the advertisements of these people, and has continued to use some
foolish little suction pump, when what his eye needed was operative
procedure or skilled therapeutics.
If I should sum up my opinion of massage in the reduction of
intra-ocular tension, I would say that it is useful in enhancing the
action of myotics, and particularly useful, as Domec, Knapp, Ohm, Weeks
and many others have shown, after the filtering angle has been opened by
a proper operative procedure. It seems to me that it is distinctly our
duty to inform patients that it is no panacea, and that they must never
trust themselves in the hands of irregular practitioners who pretend to
cure all ocular ills with massage.
_Electricity._ The credit of first using high frequency currents in the
treatment of glaucoma belongs to Truc, Imbert and Marques, and Roure's
experiments indicate that this current suitably applied appears to have
an influence not only in reducing the arterial tension, but also the
ocular tension. Thus, in an interesting series of experiments he has
been able to reduce an arterial pressure of 200 mm. to 140 mm., and an
ocular tension of plus 2 to the normal after eighteen applications of
the high frequency current. The current is applied for ten to fifteen
minutes at a time twice a week. Some surgeons, for example, Wuerdemann,
have suggested the use of electricity combined with massage, and have
apparently achieved satisfactory results.