History of Iridotomy / Knife-Needle vs. Scissors—Description of Author's V-Shaped Method

by S. Lewis Ziegler

I. KNIFE-NEEDLE METHOD.

Cheselden,[3] a renowned surgeon, and oculist to Her Majesty, Queen Caroline of England, first announced, in 1728, his success in making an artificial pupil by means of his knife-needle. He made his puncture back of the corneoscleral junction on the temporal side, passing the knife across the posterior chamber, and making a counter-puncture in the iris-membrane near the nasal margin. He then cut through the iris from behind forward as he withdrew the knife, the incision being carried through two-thirds of its extent. The pupillary opening thus made was a long oval slit, horizontally placed. He has reported two successful cases[4] (Figs. [1] and 2), occurring in patients who had previously undergone couching of the lens. His instrument, strange to say, was practically of the same general shape as the Hays knife-needle, but was larger, and judging from the description more clumsily constructed, as there was danger of leakage of the aqueous and sometimes of the vitreous when it was used. Its form resembled a combination of a bistoury and a sickle-shaped knife, having a sharp edge on one side, a rounded back, and an acute point. We possess two good illustrations of this knife-needle, one by Cheselden himself (Fig. [3]), and the other by his pupil, Sharpe[5] (Fig. [4]).

Fig. 1.—Original case of iridotomy. Iris incised above (Cheselden).

Fig. 2.—Second case of iridotomy. Iris incised below (Cheselden).

Fig. 3.—Original knife-needle in situ, behind the iris (Cheselden).

For more than a century the method of Cheselden seems to have been the storm center of controversy. Some doubted his veracity, others essayed his operation but failed, while a few had a moderate degree of success. Many attributed to him statements which do not appear in his published report. He says clearly that in each of his cases couching had previously been performed, and yet some have insisted that the lens was present, and must have been wounded. He also states that his incision was made from behind forward, and yet his followers, Sharpe[5] and Adams,[6] both describe the incision as being made from before backward. As Sharpe was his pupil, and presumably had seen him operate, Guthrie[7] suggests the possibility of his having made his incision both ways, the technic being practically the same.

Morand,[8] in his “Eulogy of Cheselden,” claims to have personally seen him operate “on an eye in which the iris was closed by an accident,” and gives a more detailed description which closely follows the original method. He states that Cheselden presented him with one of his knife-needles as a souvenir of the occasion. Although Morand does not record the exact date of his visit to London, he does state that it occurred during the year 1729. Huguier,[9] in his exhaustive thesis on artificial pupil, also places the date of this visit in the year 1729. This fact is important, as some writers have declared that Morand neither made the visit to London nor saw Cheselden operate, but only quoted the original account given in the Philosophical Transactions. The publication of Morand’s high encomiums in 1757 attracted renewed interest to the subject of Cheselden’s operation among men of scientific and medical attainments.

Sharpe,[5] in 1739, performed this operation in the same manner as Cheselden, except that after he had entered the knife-needle through the sclerotic he passed it through the iris and across the anterior chamber, and then incised the iris-membrane from before backward. Although he was Cheselden’s pupil, and dedicated his small volume on surgery to him, he probably did his master more harm than good, as all the objections to Cheselden’s method seemed to be based on the deprecatory remarks of Sharpe. He says, “I once performed it with tolerable success, and a few months after, the very orifice I had made contracted and brought on blindness again.” He mentions the danger of wounding the lens, the lack of success in paralytic iris with affection of the retina, the danger of iridodialysis from traction of the knife, and the possibility of failure because the incision would not enlarge sufficiently. Thirty years later (1769) he published the ninth edition of his book without recording a single additional case, but added the thought that, since extraction of the crystalline lens showed the cornea was not so vulnerable as had been believed, he would “imagine” that a larger knife might be introduced perpendicularly through the cornea and iris and a similar incision made. In his first eight editions he pictures Cheselden’s iris-knife (Fig. [4], vide p. 25), but in his ninth edition he substitutes a broad lance-knife with two edges which closely resembled the one Wenzel (vide Fig. [17]) had just introduced (1767), and which Sharpe suggests “can also be used for the extraction of the cataract.” He evidently did not have a very clear idea of the subject, and only succeeded in casting doubt and discredit on the method of Cheselden, which, judging by his own statement, he had tried but once.

Heuermann,[10] in 1756, had already antedated these thoughts of Sharpe by practising a similar method. He passed a double edged lance-knife through the cornea instead of through the sclera, and then made a sweeping incision through the iris-membrane without enlarging the corneal wound. He was probably the first to puncture the cornea with the iris-knife.

Janin,[11] about 1766, performed Cheselden’s operation several times with but little success owing to reclosure of the wound by plastic exudate. He adopted Sharpe’s modification, but later on changed the incision from a horizontal to a vertical one with better results. He, however, afterward abandoned this procedure and became the originator of the other school, composed of those who preferred to use the scissors.

Guérin,[12] in 1769, made a free corneal incision with a large cataract knife, and then introduced a small iris-knife, with which he made a crucial incision from before backward in the center of the iris-membrane. Although Guthrie[7] distinctly states that Guérin afterwards removed the four angles of the cross with a pair of scissors in order to prevent reclosure of the incision, no direct confirmation of this statement can be found in his writings.

Beer,[13] in 1792, first published his method, which he designated as “an improvement on Cheselden’s method.” Although the technic is somewhat different, the procedure is practically the same as that originated by Heuermann in 1756. Beer selected certain cases in which a prolapsed iris had followed the lower incision for cataract, causing adherent leucoma with a tensely drawn iris-membrane. He plunged his double-edged lance-knife (Fig. [5]) through the cornea and stretched out iris, from above downward and a little obliquely (Fig. [6]), so as to incise the center of the tense iris fibers crosswise, at right angles to the line of traction; cutting horizontally when the traction was vertical, and vertically when this was horizontal. In his monograph on artificial pupil,[14] 1805, he substitutes for the lance-knife his new broad iris-knife, which is practically the same as that later shown by Walton (vide Fig. [12]), as, indeed, Walton’s procedure (vide Fig. [13]) was almost identical with that of Beer. For other conditions he usually employed Wenzel’s operation until by chance he encountered a puzzling case which led him to perform the operation we now know as iridectomy (1797) and which thereafter became his favorite procedure for artificial pupil.

Fig. 6.—Beer’s iridotomy with broad iris-knife (after Mackenzie).

Adams,[15] in 1812, revived the operation of Cheselden with certain modifications. While his puncture was made in the same location, his technic was different. He entered the sclera with a small iris-scalpel of his own special design (Fig. [7]), which, like Sharpe, he passed through the iris-membrane into the anterior chamber, carrying it across to the nasal side (Fig. [8]). From entrance to exit he always kept the edge of the knife turned back toward the iris, so as to cut from before backward. He was thus able by the most delicate pressure of his instrument, to make a long horizontal incision, without causing iridodialysis (Fig. [9]). If the first incision appeared to be too short, he did not withdraw the knife entirely, but again carried it forward and partially withdrew it, always cutting in the same plane. To quote his own words, “by repeating the efforts to divide the iris (taking care in so doing to make as slight a degree of pressure as possible upon the instrument, instead of withdrawing it out of the eye at once, as recommended by Cheselden), a division of that membrane may, in almost all cases be effected, of a requisite size to establish a permanent artificial pupil” (Figs. [10] and 11).

Fig. 8.—Adams’ iris scalpel in situ, showing location of scleral puncture (after Lawrence).

Fig. 9.—Iridotomy by Adams’ method (after Lawrence).

Fig. 10.—Occlusion of pupil (Adams).

Fig. 11.—The resulting pupil after iridotomy (Adams).

Here were three elements of success, a sharp knife, a gentle sawing movement, and the most delicate pressure of the instrument. His method was a decided advance, and he reported success in nearly one hundred cases. Others, less skilful, however, failed of success, and the severe criticisms of Scarpa,[16] though evidently unjust and tinged by personal animosity,[17] cast a shadow of doubt on the method.

Fig. 13.—Iris-knife in position to make central pupil (Walton, after Beer).

From that time on for nearly half a century this form of iridotomy was practically abandoned, the pendulum swinging toward the use of scissors, which Maunoir had popularized and Scarpa had indorsed. Walton,[18] however, about 1852, proposed a method closely resembling that of Heuermann and almost identical with that of Beer (vide Fig. [6]). His iris-knife (Fig. [12]) was practically the same as the broad iris-knife of Beer. He incised the cornea near the limbus, and passed the knife across the anterior chamber to the middle of the iris-membrane which he punctured with a sweeping vertical incision (Fig. [13]). If the tissue still retained its elasticity there appeared a long pupillary aperture, elliptical and vertical (Figs. [14] and 15). This incision, however, like all those made through a single set of the iris fibers, was only successful when there was sufficient resiliency remaining in the iris tissue to draw the slit open, and thus keep the edges from uniting. While this method never became very popular, there were some who later practiced it by substituting a very narrow Graefe knife for the iris-knife of Heuermann, Beer and Walton. In fact, this latter procedure still has considerable vogue, both for iridotomy and capsulotomy.

Fig. 14.—Occlusion of pupil (Walton).

Fig. 15. New pupil after incision with iris-knife (Walton).

During the following seventeen years no notable advance was made, the scissors method still retaining its hold on the profession, until in 1869, von Graefe, after long reflection, became convinced of the dangers of that method, and communicated to one of his pupils, M. Meyer, his method of simple iridotomy performed with the knife-needle. Meyer[19] quotes his views as follows:

“For such cases von Graefe has suggested another method of operation, the principle and execution of which are contained in the following note written for us by that illustrious savant in 1869:

“When, in consequence of a cataract operation, the lens is absent, and when there is highly developed retro-iritic exudation, with disorganization of the iris tissue, flattening of the cornea and the other sequelæ of a destructive iridocyclitis, I substitute simple iridotomy for iridectomy, which is the operation hitherto performed, generally without success. The operation consists in inserting a double-edged knife, resembling in shape a very sharp pointed lance-knife, through the cornea and newly formed tissues till it pierces the vitreous body, and immediately withdrawing it; and, while withdrawing it, enlarging the wound in the membranes without increasing the size of the corneal wound. Experience shows that such plastic membranes attached to the atrophied iris and to the capsule of the lens have a tendency to contract sufficient to maintain, to a certain extent, the opening which has been made.

“If, in the ordinary method of iridectomy, combined with laceration or extraction of the false membranes, we find that the artificial pupil usually becomes closed, we must attribute this to an excessive vulnerability, which immediately sets up proliferation in those tissues which have been touched, and which are endowed, in consequence on their structure, with an irritability altogether peculiar. We know that even the transitory reduction of the intraocular pressure, which follows the evacuation of the aqueous humor, is sufficient to give rise to hemorrhage in the anterior chamber, which interferes with the perfect success of the intended operation; but most of our failures in the ordinary methods are due to the irritation caused by the forceps and the traction on the surrounding structures. Simple iridotomy is free from such inconveniences; it is, so to speak, a sub-corneal act, and enjoys the immunity which belongs to subcutaneous operations.

“I have also reduced the corneal wound to a minimum, by using small falciform knives. These are passed through the false membranes, which are then cut from behind forward.”

Von Graefe thus proposed two methods, (1) by cutting from before backward with a double-edged lance-knife, according to the method of Heuermann, and (2) by cutting from behind forward with a sickle-shaped knife, after the original suggestion of Cheselden. Later in the same year, as he lay on his last bed of illness, he became so absorbed in the study of this subject that he sent a telegram to the Heidelberg Congress[20] (September, 1869), in which he advocated the method by the sickle-shaped knife-needle as the best procedure. His last message to his colleagues showed, therefore, that through mature conviction he strongly favored the use of the knife-needle, and the making of a sub-corneal incision in the iris-membrane without evacuating the aqueous humor. His untimely death, however, prevented him from further perfecting this procedure and presenting it to the profession.

Galezowski,[21] in 1875, published a somewhat similar method in which he used his falciform knife, aiguille-a-serpette (Fig. [16]), which he introduced through the cornea and iris-membrane, making either a horizontal or a vertical incision, with a “go-and-come” (sawing) movement, after the suggestion of Adams. If this single cut was not sufficient, he made a linear incision of the cornea with a Graefe knife, drew out the iris and cut it off with scissors. By a process of evolution, however, he perfected the former procedure and eliminated the scissors. This latter method was published in the third edition of his book in 1888. He punctured the cornea and iris-membrane with the sickle-shaped knife, making first a horizontal incision by the sawing movement of Adams, and finishing with a second cut in the vertical direction, thus forming a T-shaped incision. In actual practice, however, he almost always prolonged this second cut, thus making a crucial incision after the manner of Guérin.[12]

The writer,[22] in 1888, was led to devise an operation with a modified Hays knife-needle, in which through a corneal puncture he made a converging incision in the iris-membrane which resembled an inverted V. The resulting pupil opened up and formed either a triangular or an oval-shaped pupil depending on the degree of stiffness or resiliency of the iris-membrane. This method will be described in detail later on.