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 cla.s.sified as:
1. Those that cause a partial or complete closure of the lymph s.p.a.ces and Schlemm"s ca.n.a.l by cicatrical contraction, as in sclero-kerat.i.tis.
2. Those that cause obstruction to the lymph s.p.a.ces 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 s.p.a.ces 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 const.i.tute the final glaucoma cup. The lamina may then bridge across the s.p.a.ce 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 a.s.sociation 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 circ.u.mstances 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 ma.s.sage, vibration ma.s.sage and suction ma.s.sage, 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 pa.s.sing 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 quant.i.ties 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 cyst.i.tis. 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 antic.i.p.ate 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 ma.s.sage, and by means of electricity and diathermy._ Ma.s.sage is of ancient lineage. In general terms, in so far as ocular ma.s.sage is concerned, it may be applied to the eye with the finger tips (ordinary ma.s.sage), by means of various instruments (vibration ma.s.sage), and with the help of certain suction cups (suction ma.s.sage, which is indeed a form of vibratory ma.s.sage). Many authors are satisfied with their results without the employment of any instrument, and prefer simple ma.s.sage 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 ma.s.sage, 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 ma.s.seur 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 pa.s.sed 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 ma.s.sage 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 eyeb.a.l.l.s such ma.s.sage 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 ma.s.sage is not available, but it is of a.s.sistance 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 a.n.a.lgesia by traction on the ciliary nerves, and in reducing intra-ocular tension.
Unfortunately, it is difficult for regular physicians to make reference to ma.s.sage of the eyeball lest their words should be misquoted by irregular pract.i.tioners 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 advertis.e.m.e.nts 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 ma.s.sage 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 pract.i.tioners who pretend to cure all ocular ills with ma.s.sage.
_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, Wurdemann, have suggested the use of electricity combined with ma.s.sage, and have apparently achieved satisfactory results.
The constant current has also been much employed for the purpose of 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 pa.s.sing 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.