The method of discission is, after dilatation with atropia, to produce general anaesthesia in young children, or the use of cocaine in older subjects. The lids, separated by the speculum, and the eye steadied by fixation forceps, the needle (Fig. 79 ) or knife needle (Fig. 80) is now entered through the cornea at the temporal side, and, reaching to the opposite side of the pupil, the needle penetrates the capsule, when, by using the cornea as a fulcrum it is made to cut the capsule (Fig. 81 ). A second cut may be made at right angles to the first, although at the first operation it is better not to make too extensive laceration of the capsule, for fear of too much swelling of the lens, causing damaging pressure upon the iris or ciliary body. More extensive cutting of the cap-sule may be made at subsequent operations. Sometimes two needles may be used, entering them at opposite sides of the cornea and penetrating the lens at the centre of the pupil, then by inclining the handles toward each other, the points separate and an opening is at once made. Stop needles, which prevent a too deep entrance of the needle, are made for this purpose.
After the operation atropia should be instilled and the eye bandaged. The patient is usually kept in bed for one day, when he is allowed to get up and the bandages removed. The pupil should be kept well dilated until absorption has ceased. In young children there is usually but very little if any reaction; but the older the subject the greater is the liability to swelling and inflammatory reaction. Sometimes the lens begins to swell rapidly within a few hours, fragments of the lens substance push forward into the anterior chamber and there will be associated with it much pain and pericorneal injection. Ice compresses should be immediately applied atropia instilled and Aconite given. If not controlled within a short time and the aqueous becomes hazy, iris discolored and chemosis sets in, a large paracentesis should be made to allow of the escape of the aqueous and some of the lens substance if possible.
Discission is also made for the opacity of the capsule following extraction, and for this purpose the knife needle is always preferable. The operation is the same as just described, excepting that in secondary cataract the object is to secure by a clean cut the curling away of the divided membrane in such a manner as to give a clear pupil, and for this purpose various shaped discission have been recommended and practiced.
The shape of the discissions most generally made are plus T and (>) Knapp, Archiv, Ophthal., vol. xxi., 2, 1892. in a paper on “Glaucoma After Discission of Secondary Cataract, ” says that the first or Plus shaped discission gives the truly ideal results, i.e., pupils, and is made by making at first a horizontal incision, then, by cutting from above down to the horizontal section and from below upward in the same way. But, owing to the occurrence of glaucoma in about 1 percent. of his cases during the last six years, he has returned to the T-shaped discission. Care should be taken not to enter the knife any deeper into the involves than is necessary for a sufficient opening in the capsule. In some rare cases the use of the two needles as described may be preferable to the knife.
We believe that discission should be practiced in a large majority of cases of cataract extraction, as by so doing a greater improvement of vision can be gained. Disastrous results have been re-ported from discission, but so far we have been fortunate enough not to meet them, and hence do not consider our cataract operations completed until a perfectly clear pupil has been secured by discussion. The operation should never be made until all signs of irritation of the eye, after the extraction, has passed away. The knife must be very sharp, and all rough handling or dragging upon the resisting bands must be avoided.
Cataract Extraction.-The various methods for the extraction of a cataractous lens that have been employed by different operators would, if described in detail, form a volume in themselves. In fact, it may be said that no two operators follow precisely the same method in every detail. The experience and technique of one will vary from that of another, and, in consequence, the procedure of one varies in some details from that of the other. On account of this variance, many so-called modifications are being constantly brought forward. There are however, two essentially different methods of extraction which will be considered. viz.: Extraction with an iridectomy, and extraction without an iridectomy, or, as it is frequently called, the simple operation.
Previous to all cataract operations are certain preliminary considerations worthy of attention. As to the season of the year, it should depend upon the location, simply avoiding, if possible, extreme cold or heat. Age has less influence upon success than the general condition of the patient. Any chronic disease, such as nephritis or diabetes, that will impair the vital forces will tend to influence unfavorably recovery from the operation. A severe cough, asthma, incontinence of urine or any condition affecting the general health, should be controlled as far as possible. All sources of infection, such as suppurating wounds, erysipelas, catarrh of the lachrymal sac, conjunctivitis, etc., must be provided against.
Thorough antiseptic measures should be strictly followed out. The room and bedding should be perfectly clean and free from all sources of impurity; the patient should have the face, hair, beard and hands thoroughly scrubbed with soap and water once or twice before the operation. The surgeon and the assistant should have their hands scrubbed with soap and water and the nails carefully cleansed and then again washed in a solution of mercury or car-bolic acid. The instruments are thoroughly cleansed either in a solution of bichloride of mercury, 1 to 2,000, or in carbolic acid, 1 to 200, with the exception of the knife, which is immersed in a solution of boracic acid, or few minutes in boiling water. The face of the patient is then washed with one of the above solutions, taking great care to cleanse the margin of the lids at the root of the ciliae. The conjunctival sac, especially if it contains any secretion, should be flooded with a 1 to 8,000 solution of the bichloride of mercury. General anaesthesia is not employed unless the patient is particularly nervous and unmanageable, when ether is administered. A2 or 4 percent. solution of cocaine is dropped upon the cornea two or three times, at intervals of about ten minutes, when local anaesthesia is complete.
Extraction with Iridectomy.-This operation as most generally performed is practically that introduced by von Graefe as his modified linear operation, the slight variations or so-called modifications being merely a sight variance in the position of the incision. Anaesthesia being complete, the speculum is inserted and the globe steadied with the fixation forceps. The knife is then entered by making the puncture at the corneo- scleral margin at a point on a level with a semi-dilated pupil. The direction of the knife when making the puncture is toward the centre of the pupil, and when well in the anterior chamber, is gradually, while being pushed across the chamber, brought parallel to the horizontal diameter until its point comes directly on a level with the puncture. The counter-puncture is now made and the knife cut out so that the whole section is about in the corneo-scleral margin. (See Fig. 87.) This first stage of the operations varies, as already referred to, with different operators merely as to the position of the puncture, counter- puncture and the completion of the section above, some making it further in the cornea and others deeper in the sclera, and some making a conjunctival flap above. In making the counter-puncture the point may catch in a wrong position, when it may be slightly withdrawn and entered again, care being taken not to increase the size of the opening at the point of puncture and allow of the escape of the aqueous. In cutting out, the iris may fold over the knife, when one of two procedures should be followed-either slowly withdraw the knife and postpone the operation, or preferably complete the section, cutting through the iris, which does not materially interfere with the success of the operation, except by the bleeding in the anterior chamber.
After the completion of the section, the iris, if not previously removed, is seized at its pupillary border with the iris forceps and gently drawn out. As but a small iridectomy is necessary, no undue traction should be made upon the iris. The iris should be severed by one cut of the scissors, and, if its edges become caught in the wound, it may be made to free itself by gentle friction with the lid, or be replaced with the spatula.
The cystotome is then introduced into the chamber, the back of the instrument preceding and its cutting point held parallel to the surface of the lens; it is now pushed downward to the lower margin of the pupil or even beneath the iris, and the point turned toward the lens, the capsule of which it readily pierces. The division of the capsule is usually made by drawing the cystotome from the lower border directly upward, making a vertical incision through the capsule, and then a horizontal incision crossing it above, making a T-shaped opening. My method has been that practiced by Knapp, making a peripheral cystotome. The larger the opening in the capsule the lens is removed.
Professor of Ophthalmology in the College of the New York Ophthalmic Hospital; Surgeon to the New York Ophthalmic Hospital. Visiting Oculist to the Laura Franklin Free Hospital for Children; Ex-President American Homoeopathic Ophthalmological, Otological and Laryngological Society. First Vice-President American Institute of Homoeopathy : President Homoeopathic Medical Society of the State of New York ; Editor Homoeopathic Eye. Ear and Throat Journal : Associate Editor. Department of Ophthalmology, North American Journal of Homoeopathy, etc.