Dr. Casey A. Wood's Paper on Operations Other than Scleral Trephining for the Relief of Glaucoma Discussion, Albert E. Bulson, Jr. , M.D., Fort Wayne.

Increasing belief in Colonel Elliot's view that trephining should be the operation of choice in any form of glaucoma, makes it difficult to consider operations other than trephining in anything but a spirit of disfavor.

Until recently the decision as to the kind of operative procedure to be employed for the relief of glaucoma has depended on the form and stage of the disease, and the amount and character of the vision of the affected eye. Many operators still hold that an iridectomy is the most valuable of all operations for acute inflammatory glaucoma, and not a few hold that the operation has a decided place in the treatment of simple glaucoma. The operation is not without difficulties, and one is inclined to agree with Elliot who says that "The man who can make a 'finished iridectomy' quietly and cleanly has graduated as an ophthalmic operator." The difficulties of an iridectomy are especially pronounced in those cases in which the anterior chamber is extremely shallow and the iris is pressed against the cornea. It is in such cases that the success of the operation is increased by the addition of posterior sclerotomy and the intelligent use of miotics prior to the performance of the iridectomy. Even then the permanent results of the iridectomy will be modified in proportion to the success secured in freeing the filtration angle and opening Schlemm's canal by thorough removal of the root of the iris.

The failure of many apparently well executed iridectomies may be attributed to the fact that the iris is not removed to the extreme root, and the remaining stump is sufficient to block the drainage. This is especially apt to be the case in chronic glaucoma where the iris is adherent to the cornea, and in efforts to free the filtration angle by an iridectomy the iris is torn off in front of the adhesion and the filtration angle is not opened.

As Elliot has pointed out, iridectomy is most open to attack on the ground of safety. We have to take into account the large scleral wound made, and the fact that this lies close to the ciliary body. The sudden release of all tension and the simultaneous weakening of the supports of the lens and vitreous body create very unfavorable conditions under which to make the crucial step of the operation.

The poor results following an iridectomy in chronic glaucoma have led to the devising of many substitute operations, of which those tending to the production of a filtering scar are now preferred, and, experience shows, hold out the most hope of bringing about long continued relief. It even is considered probable that the effects of an iridectomy which brings about more or less permanent reduction in the intra-ocular pressure is due to the formation of a filtering scar which augments whatever results may have been secured in the attempt to open up the drainage into the canal of Schlemm.

Dr. Wood has referred to several of the many substitutes for iridectomy that have been proposed, and it is unnecessary to enumerate them again or to attempt to point out their good or bad features. It is sufficient to say that for the average operator and the larger per cent of cases, the operation which is easiest to perform, is attended with the least risk and offers the best hope of permanent results should be the one of choice. Sympathectomy has failed to secure a place in ophthalmic surgery, sclerotomy has not been found adequate, and cyclodialysis is not sufficiently simple of execution or permanently beneficial in its results to give it prominence.

Of the operations proposed for the formation of a filtering cicatrix, those of Elliot and Lagrange are justifiably the most popular. Those of us who have had the pleasure of seeing the trephining operation done by Col. Elliot are impressed with the fact that the operation, even in the hands of its originator, is not, when properly done, uniformly easy of performance. It does, however, offer the advantage of carrying with it the minimum amount of risk, and the apparently permanent results secured justify the ophthalmologist in acquainting himself with the technique of the operation, for, as pointed out by Sydney Stephenson and others, "the technique is responsible for success or failure." Furthermore, there is no sufficient reason why the field of usefulness of the operation should be confined to the chronic forms of glaucoma, and Col. Elliot unhesitatingly recommends trephining as safer and more efficient than any other operative procedures at present employed for the relief of acute glaucoma.

The success of the Lagrange operation, which, like the Elliot operation, aims to produce a fistulous communication between the anterior chamber and the sub-conjunctival area, depends upon securing the removal of a relatively large section of all of the layers of the scleral and corneal lip of the wound, so that a permanent opening, covered by the replaced conjunctival flap, is made. Unlike the trephine operation which was evolved from it, the Lagrange operation requires the same kind of an opening of the eyeball as required for a well executed iridectomy, and a properly placed section entirely in scleral tissue, with a good sized conjunctival flap, are elements which enter into the ultimate success or failure of the procedure.

Aside from the dangers incident to a wide incision in the neighborhood of the ciliary body and the possibility of accident to the lens or vitreous body, or of intra-ocular hemorrhage, there is for the average operator the added difficulty and danger in removing a piece of sclera of the exact size required. The technique of the operation is even more difficult and exacting than in the performance of the trephine operation, and it also compares unfavorably in safety.

The advisability of removing the conjunctival flap, as advocated by Dr. Wood, as a modification of the Lagrange operation, may be seriously questioned, for aside from the fact that apparently no advantages in aiding permanent filtration are added, there is, added to the objections to the Lagrange operation already mentioned, the very serious disadvantage of subjecting the area at the root of the iris to infection for a prolonged period of time. The advantages of the protection afforded by a conjunctival flap far outweigh the disadvantages of a remotely possible interference of drainage by the blocking of the open wound with conjunctival tissue. The fortunate experience of Dr. Wood in not having infection in a wound which remains open and unprotected for variable lengths of time is not likely to be the experience of any considerable number of operators, and probably will not always be the experience of Dr. Wood. Furthermore, the possibilities of damage by hemorrhage from the choroidal or retinal vessels, delayed formation of the anterior chamber and adhesion of the capsule of the lens to the wound, and the injurious effects of even slight trauma subsequent to the operation, including loss of vitreous, are increased by omitting the conjunctival flap.

The modern operation for the relief of glaucoma, by which a filtering scar is produced which permits escape of liquid from the anterior chamber, is the one which apparently holds out the most hope of permanently relieving the condition. While success will depend always to a certain extent upon the personal equation, yet it seems now that for a large majority if not all of the cases we are justified in abandoning all other operations than trephining, notwithstanding the verdict of Elschnig and others that fistula forming operations eventually will be discarded in favor of iridectomy and cyclodialysis.

Late or secondary infection, not unknown following iridectomy, may follow the trephine operation, and already some fifteen or sixteen cases have been reported. But while this possibility is a real danger, which improved technique may greatly minimize (Col. Elliot has not seen a case of secondary infection in an experience of over 1200 trephining cases of his own and a large number of others performed by his assistants and pupils) the ultimate verdict must rest with results as compared with other measures. At present, as pointed out by Meller, whose statistics Dr. Wood has cited, trephining heads the list of remedial measures for the relief of glaucoma, and it has the advantage of being applicable to any form of the disease, to be relatively free from danger, either immediate or remote, and to produce the highest percentage of favorable results. The addition of an iridectomy in every case of trephining does not unduly complicate the operation and has much to commend it in offering the patient every possibility of relief.