MICROSURGERY IN CHRONIC SIMPLE GLAUCOMA*

OTTO BARKAN, M.D.San Francisco

The writer has recently reported anoperative procedure!' 2 for the relief ofchronic simple glaucoma which consistsof opening Schlemm's canal under directmagnified vision. This procedure removesthe block to the circulation of intraocularfluid, which can be shown to be the me­chanical cause of the increased intraocularpressure, and thereby restores to the in­traocular fluid its physiological directionof outflow, instead of creating an abnor­mal outlet with the frequent complicationsand sequelae that may follow present-dayoperations. By means of a contact glassthat has been devised for this special sur­gical purpose the operator can see the areaof blockage and can watch and guide hisinstrument during the operation. Theoperative procedure when thus performedis without danger and its objective­namely, the opening of Schlemm's canal--can be deliberately performed with thetrabeculum under full view. In those casesin which the trabeculum was incised overa sufficient extent, the intraocular pres­sure has returned to normal. According toobservations during the last 10 years theresults show promise of being permanent.

In this article a variation of techniqueis suggested that will more certainly in­sure the opening of the canal. The origi­nal technique 0 f operating under X4 mag­nification affords a convenient range ofsome 20 em. and a fairly wide field. Be­cause of the moderate degree of magni­fication, however, one cannot be quite cer­tain of always striking the canal and ofopening it over a sufficient extent in allcases. In those cases in which the canalwas insufficiently opened the intraocular

* Read before the Eye, Ear, Nose andThroat Section of the California Medical Asso­ciation at Del Monte, California, May, 1937.

pressure has been only partially reduced,and a later operation has been necessaryto secure normal pressure. The technicalvariation suggested in this article consistsof increasing the magnification from X4to X 20. This increase of magnification isobtained by using the binocular cornealmicroscope attached to the surgeon's headby means of a helmet (fig. 1). Althoughnot easy of performance, the assurance ofopening Schlernm's canal afforded by thishigher degree of magnification may prove

Fig. 1 (0. Barkan). Photograph showingthe use of the binocular corneal microscope inthe author's operation of opening Schlemm'scanal under direct vision.

to be an improvement over the originaltechnique in those cases where it is indi-cated. .

Microsurgical technique of openingSchlemm's canal under direct vision. Thesurgeon wears a helmet to which is at­tached a binocular corneal microscope. Hehelps to steady the microscope with hisleft hand which, in turn, by means of afinger, keeps in contact with the patient'shead. A trained assistant, standing behindthe patient's head for the left eye and athis right side below the head for the right

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eye, secures the bulbus at the temporallimbus with a smaIl Elschnig forceps heldin his right hand. With his left hand hesteadies the surgical contact glass bymeans of a double-pronged probe whichfits into two depressions on the convexsurface of the glass. A second assistantguides the narrow beam of the hand lampfrom across the bridge of the patient'snose to transilluminate the nasal portionof the limbus and the corresponding re­gion of the angle of the anterior chamber.The surgeon supports and focuses themicroscope with his left hand while heguides the knife with his right hand. Hesits on a stool adjusted to such a heightthat by means of a slight movement of hishead his gaze may be directed first at thelimbus and then transferred above thetemporal edge of the contact glass to theanterior chamber, from which point hecontinues to guide the knife across thechamber by direct vision through theglass. When the blade reaches the highlymagnified angle its point is inserted exact­ly into that portion of the trabeculumwhich covers Schlemm's canal and theincision is continued for several milli­meters along this line. That this may beaccomplished with a high degree of cer­tainty and exactitude is proved by post­operative biomicroscopic examination ofthe angle, which shows a single straightdehiscent slit of the trabeculum openingSchlemrn's canal. What appears to be theglistening-white inner lining of the op­posite side of Schlemm's canal is clearlyvisible through this longitudinal bisectionof its wall. (The sclerocorneal trabeculummay be found to be bisected or sometimestorn off, constituting what may be calledeither a trabeculotomy or trabeculectomyas the case may be.) The working rangeis 6 em. from the patient's eye to the tipof the objective, or 20 em. from the pa­tient's eye to the eye of the surgeon. The

surgeon keeps the image in focus by shift­ing his head and makes the finer adjust­ments with the sliding scale of the micro­scope, for which the fingers of the left,steadying hand are used.

The binocular corneal microscope hasin the past been used by many ophthal­mologists for the removal of foreignbodies from the cornea. This procedurehas been found satisfactory in routinepractice, the patient sitting upright withhis head on the chin rest. RecentlySchoenberg'! has suggested its use forintraocular surgery, and reports attachingthe head of the corneal microscope to astand on a table at the side of which thepatient is lying, in order that it may beused in the course of surgical operations.He suggests that various uses are possiblebut does not, as far as can be gatheredfrom reading his article, report havingactually applied it to intraocular surgerynor proved its practicability for this pur­pose. Before reading his article such ause had occurred to me for my micro­gonioscope/ which consists of a binocularmicroscope mounted on a highly flexiblestand. However, the semirigidity of eventhis very flexible apparatus renders it un­satisfactory for purposes of intraocularsurgery. It was for this reason that I re­moved the microscope head from its standand attached it to the surgeon's head,where, with the additional steadying in­fluence of the surgeon's hand, whichmaintains contact with the patient's head,it works out satisfactorily. Contact withthe patient's head is found to be necessaryif one considers that the slightest move­ment between microscope and object ismagnified 20 times, and if one furthertakes into account the narrow breadth offocus and realizes thatthe limited field ofvision when using the X2 objective andX 10 ocular combination is only 6.9 mm.in diameter.

MICROSURGERY IN CHRONIC SIMPLE GLAUCOMA 405

CONCLUSION

Examination of the living eye with thebinocular corneal miscroscope is custom­arily called biomicroscopy; examinationof wet specimens of the eye with the sameinstrument has been termed micro­anatomy! To operate within the livingeye with this technique may be aptlytermed intraocular microsurgery. As faras could be judged from a review of theliterature, this is the first time that such

high magnification has been applied in in­traocular surgery.

The use of the binocular microscope,although it demands deliberate care andtrained assistance, is feasible and mayprove to be the procedure of choice whenoperating on Schlemm's canal underdirect magnified vision in those occasionalcases where extra assurance of strikingthe canal is required.

490 Post Street.

BIBLIOGRAPHY

t Barkan, Otto. A new operation for chronic glaucoma-Restoration of physiological functionby opening Schlemm's canal under direct magnified vision. Amer. Jour. Ophth., 1936, v. 19,Nov., no.lI, p. 951.

--. Recent advances in the surgery of chronic glaucoma. Trans. Amer. Acad. Ophth,and Otolaryn., 1936, p. 469; Amer. Jour. Ophth., 1937,v. 20, p. 1237.

• Schoenberg. Binocular microscope for delicate surgery. Trans. Amer. Ophth. Soc., 1935,v.33,p.401.

• Troncoso, D., and Castroviejo, R. Microanatomy of the eye with the slitlamp microscopeAmer. Jour. Ophth., 1936, v. 19, May, no. 5; June, no. 6; July, no. 7.