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."