The method of opening the capsule with the point of the knife or needle is useful in cases of extraction without iridectomy; the pupil should be dilated before the operation.

=Fourth step.= _Delivery of the lens_ is performed by a gentle pressure, combined with ma.s.sage, on the extreme lower margin of the cornea with a curette or spoon, until the upper margin of the lens presents in the wound, when the pressure is gradually made upwards over the cornea until the lens is delivered. Delivery of the lens may be prevented by--

(_a_) Imperfect opening of the capsule, which is usually the result of using a blunt cystotome; if capsule forceps are used this difficulty hardly ever arises.

(_b_) Too small an incision. The margin of the nucleus may present and not be able to pa.s.s the wound. The wound must then be enlarged with the iris scissors and the lens delivered in the ordinary way. Only by experience can the amount of pressure required for the delivery of the lens be gauged.

[Ill.u.s.tration: FIG. 98. OPENING THE CAPSULE WITH FORCEPS IN CATARACT EXTRACTION. The forceps are inserted closed, brought in contact with the lens, opened, and the capsule grasped between the blades and withdrawn by a gentle side-to-side movement.]

(_c_) A sticky consistency of the cortex is not infrequently found in cases of immature cataract. When the lens presents and cannot be delivered readily it may be helped out by means of the cystotome plunged into its substance, pressure being used on the cornea at the same time.

If from these or any other causes the suspensory ligament rupture and the vitreous present in the wound, the lens should be removed with the vectis. The vectis, which should be made of stiff steel, is pa.s.sed vertically into the incision and behind the lens nucleus by depressing the handle; with a steady gentle pressure forwards it is then withdrawn together with the nucleus. The forward pressure should be such as to prevent the instrument slipping on the nucleus, for if it does so the accident is nearly always followed by a rush of vitreous. A Pagenstecher's spoon may be used instead of the vectis, and is to be preferred in cases where a small nucleus is suspected, since the latter may slip through the loop of the vectis and fail to be delivered.

=Fifth step.= _Toilet of the wound._ After the nucleus has been extracted, all the soft matter should be removed as far as possible by gentle expression with the spoon. The angles of the coloboma in the iris should be replaced by stroking it inwards on its anterior surface with the iris spatula, paying particular attention to the angles of the wound (Fig. 99). The spatula should also be pa.s.sed throughout the extent of the wound so as to free it from any capsule which may have prolapsed into it. The conjunctival flap is then placed in position by stroking it upwards with the iris spatula.

[Ill.u.s.tration: FIG. 99. CATARACT EXTRACTION. Replacing the iris, and any tags of capsule which may be in the wound, with an iris spatula.]

=After-treatment.= Atropine is instilled either at the time of operation or at the first dressing, and continued until all signs of redness of the eye have disappeared. The patient should remain in bed for at least ten days, both eyes being bandaged during the first four days. The eye that has been operated on should be covered for at least two weeks; subsequently a shade or dark gla.s.ses should be worn.

=Modifications.= The operation may be modified in various ways.

=The incision.= _The position_ of the incision has undergone many modifications. The one described above is now in general use.

_The size_ of the incision should be increased when (_a_) a large nucleus is expected, as in old people; (_b_) an immature cataract is to be extracted; or (_c_) a fluid vitreous is suspected, so that the lens may be delivered with as little pressure as possible.

=The iridectomy= may be omitted. _Extraction without iridectomy_ is undoubtedly the ideal operation; it leaves the pupil unbroken and the eye looking normal to external appearance. Further, the pupil reacts more strongly to light than if an iridectomy has been performed. The presence of the iris further prevents the prolapse of any capsule into the wound. At the same time it is attended with considerable risk of prolapse, which, as has been pointed out, is a very great danger to the eye. With proper care this probably only occurs in about 5% of the patients operated upon, but is so serious that the opinion of most surgeons is in favour of the combined method (iridectomy and extraction); but at the same time it is the practice of many surgeons to omit the iridectomy under the following circ.u.mstances: first, if the patient be young and the deformity will interfere with his getting employment; secondly, if extraction of the lens in its capsule be performed the unbroken circle of the iris will help to prevent the prolapse of the vitreous which is otherwise so liable to take place.

[Ill.u.s.tration: FIG. 100. MCKEOWN'S IRRIGATION APPARATUS FOR WASHING OUT THE ANTERIOR CHAMBER. The second and third terminals are the most useful.]

Eserine (gr. ii ad ?i) should be used to prevent prolapse of the iris after the extraction has been performed, and should be continued once a day until a good anterior chamber is present, which is usually in about twelve to twenty-four hours, when atropine should be subst.i.tuted. If the iris betray any liability to prolapse after the operation, as shown by the drawing upwards of the pupil, an iridectomy should be performed before the patient leaves the table. In any case the eye should be examined on the evening of the operation, and, if prolapse has occurred, that portion of the iris should be removed. If a prolapse of the iris occurs and is not discovered until the wound has healed, the conjunctiva should be dissected off the surface in the form of a flap and the iris tissue drawn out of the wound and removed, the angles caught in the scar being freed if possible. The opening in the globe is subsequently closed by replacing the conjunctival flap in position, or, if it has not been possible to preserve the conjunctiva over the cicatrix, by raising a flap from the ocular conjunctiva in the neighbourhood and st.i.tching it down over the opening in the globe. Not infrequently this operation is followed by an attack of acute iritis, which usually subsides under treatment.

_Preliminary iridectomy._ The iridectomy may be performed at a previous operation. It has the advantages that the surgeon learns how the patient will behave under operation, and how the eye will react to such an operation. There is an absence of bleeding at the second operation, which makes it easier, and there is less liability for the iris to become adherent to the capsule. The disadvantages, which seem to outweigh the advantages, are that there is a double chance of sepsis, and that the patient has to submit to two operations when one is sufficient. It is only performed by the author in cases in which there is a tendency to increased tension in the eye due to swelling of the lens in the early stages of the cataract. When a preliminary iridectomy is performed a keratome may be subst.i.tuted for the Graefe's knife in making the incision for the iridectomy, a much smaller one being necessary.

=Delivery of the lens by irrigation.= McKeown removes the soft lens matter by a process of irrigation into the anterior chamber, a practice not yet much adopted, but of considerable service in removing the soft matter after the extraction of the nucleus, especially in immature cataract. It is also probable that the thorough removal of the soft lens matter by this method reduces the number of cases of cyc.l.i.tis following the operation, since the soft matter forms a suitable medium for the growth of organism. The apparatus used is shown in Fig. 100, nozzle No.

2 being the most useful; it is inserted into one angle of the wound and a stream of sterilized normal saline solution at 39C. (in the flask) is allowed to flow into the anterior chamber; this stream is obtained by raising the flask until sufficient pressure is obtained. An undine may be subst.i.tuted for the flask. Care should be taken that there is a free return of fluid from the anterior chamber; irrigation should be continued until as much as possible of the soft matter has been removed.

=Extraction of the lens in its capsule.= This operation is frequently performed in India, where patients will often not return for needling of secondary cataract (capsulotomy). Although the method undoubtedly yields good results, the percentage of eyes damaged by loss of the vitreous must be higher than when the posterior capsule of the lens is left intact. The operation may be performed with or without an iridectomy, the lens being removed by pressure on the cornea with a large strabismus hook. If the vitreous should present, the lens should be removed with the vectis.

Extraction of the lens in its capsule is also performed when the lens is dislocated and causing irritation. If the lens be in the anterior chamber immediate extraction is called for, as glaucoma is a usual complication. Eserine is first instilled in order to contract the pupil and prevent the lens pa.s.sing back into the posterior chamber; an incision is then made as for a cataract extraction and the lens removed by means of the vectis. Complete dislocation of the lens into the vitreous rarely requires operation, as the patient is able to see.

Partial dislocation (luxation) occasionally calls for extraction, the vectis usually being employed for delivering the lens, but before undertaking the operation an attempt should be made to get the lens into the anterior chamber by dilating the pupil and making the patient lie face downwards; if this is successful eserine should be instilled to contract the pupil behind the lens and so retain it in the anterior chamber, from whence it can more easily be extracted. Some surgeons prefer to fix the lens with a needle pa.s.sed through the sclerotic behind the ciliary body before making the incision.

=Subconjunctival extraction.= In order to diminish the risks of sepsis, more especially in cases in which the conjunctiva is affected with trachoma, some continental surgeons deliver the lens into a pocket beneath the conjunctiva, whence it is subsequently removed. The operation has the additional advantage of a better blood-supply to the corneal flap, which is also held in better position after the operation.

_Operation._ A section upwards is made with a Graefe's knife as in the ordinary method of extraction previously described, the lens capsule being opened with the point of the knife as it is pa.s.sed across the anterior chamber. When the section through the sclerotic has been completed and the knife lies entirely beneath the conjunctiva it is withdrawn.

The wound in the conjunctiva on the outer side is then enlarged upwards with scissors, and an iris spatula is pa.s.sed beneath the conjunctiva from the small wound on the inner side and the point made to appear in the wound on the outer side; by this means the conjunctiva is raised on the spatula, and by means of sharp-pointed scissors a pocket is made in an upward direction by undermining the conjunctiva (Fig. 101). Delivery of the lens is then performed into this pocket, from which it is subsequently removed, the conjunctival wound on the outer side being closed with a st.i.tch. The advantage of this form of subconjunctival extraction over other forms which have been devised is that if difficulty is met with in delivering the lens, &c., the operation can be readily converted into an ordinary extraction by completing the division of the conjunctival flap.

[Ill.u.s.tration: FIG. 101. SUBCONJUNCTIVAL EXTRACTION. The section in the sclerotic being completed with a Graefe's knife, the figure shows the method of undermining the conjunctiva to form a pocket into which the lens is delivered and from which it is subsequently removed.]

=Complications.= These may be immediate or remote.

=Immediate.= 1. If the knife-point become entangled in the iris as it is pa.s.sed across the anterior chamber it should be slightly withdrawn, if this can be done without loss of aqueous, the iris being thereby disengaged.[4]

[4] For the other complications which may arise in pa.s.sing a Graefe's knife across the anterior chamber, see Glaucoma Iridectomy, p. 222.

2. _Loss of the aqueous before the section is complete_ may result in the entanglement of the iris as before described, or the iris, owing to the presence of the aqueous in the posterior chamber, may bulge forward in front of the knife-blade. The latter complication is more likely to occur if the section be made too rapidly. The iris may sometimes be disengaged by depressing the handle of the knife towards the patient's chin and raising the blade towards the cornea so as to allow the aqueous in the posterior chamber to escape. If this cannot be accomplished, the section should be completed and the iris, which may be divided by the knife, removed subsequently when doing the iridectomy.

3. _Avulsion of the iris_ due to movement of the patient's head. This is more liable to take place if the eye has not been properly cocainized some time before the operation. The grasping of the iris by the forceps is always felt by the patient to a certain extent, and he should be warned not to move. Avulsion is usually not complete and only results in a larger iridectomy than was intended.

4. _Dislocation of the lens._ (_a_) When opening the capsule, either from too great pressure of the capsule forceps, or from the patient moving his head. The lens must then be delivered by the vectis. (_b_) If, in delivering the nucleus, the upper edge is not made to present by pressure on the lower part of the cornea, the nucleus, especially if it be small, is liable to be dislocated upwards beyond the incision. It must then be removed with the vectis. In cases where a small nucleus is suspected, pressure should be made on the sclerotic above the incision with a curette, as well as on the lower part of the cornea, so as to make the nucleus present in the wound.

The lens may be dislocated backwards into the vitreous; if this should happen and the lens cannot be delivered, the flap must be replaced in position and the eye bandaged. Unfortunately this complication is usually followed by irido-cyc.l.i.tis and loss of the eye.

5. _Loss of the vitreous._ There are two chief phenomena which may indicate that loss of vitreous is about to take place after the extraction of the lens.

(_a_) The wound gapes unnaturally after the expulsion of the lens, and the clear vitreous may be seen presenting in the wound in the still unruptured hyaloid membrane.

(_b_) There may be an apparent deepening of the anterior chamber owing to the fluid vitreous making its way forward through the ruptured hyaloid into that cavity.

If the vitreous presents in the wound before the lens has been removed, the latter should be delivered as rapidly as possible by the vectis, as has previously been described.

If the vitreous be lost or one of the phenomena previously mentioned occurs after the delivery of the lens, the speculum should be removed from the eye and the conjunctival flap replaced in position as quickly as possible. The eyelid is then carefully raised from the surface of the eyeball by means of the lashes held in the finger and thumb and carried downwards over the globe until it is in the closed position, and a bandage is then applied.

As little manipulation as possible should be carried out when once the vitreous has shown itself about to present, and unless the iris be obviously in the wound no attempt should be made to replace it.

Loss of vitreous may be the result of subchoroidal haemorrhage, which may only make itself manifest after the patient has been put back to bed.

Loss of vitreous is frequently accompanied by haemorrhage into the vitreous, as is seen subsequently by the floating opacities therein. As a rule these clear, and useful vision is obtained.

Detachment of the retina may follow loss of vitreous even months after operation. This complication seems more liable to occur if the vitreous which is lost in the first instance be normal and not of the fluid type.

6. _Intra-ocular haemorrhage_ (see Glaucoma Iridectomy, p. 224).

=Remote.= 1. _Panophthalmitis_ is a result of infection of the wound. It usually makes its appearance about the third day and must be treated by evisceration. Occasionally the purulent material is limited to the line of the incision or even to the anterior chamber; in the latter instance the wound should be opened up and the anterior chamber washed out with peroxide of hydrogen solution (10 vols. %). Microscopic examination of the pus should be made and a vaccine prepared and administered; in two cases so treated by the author a good recovery resulted.

2. _Escape of the aqueous beneath the conjunctiva_ usually occurs about the third day, owing to the conjunctival wound having healed without the opening into the globe being properly shut off. This is accompanied by considerable pain, with chemosis and some dema of the upper lid. It is usually distinguishable from acute iritis by the pupil being evenly dilated and discoloration of the iris being absent. The condition usually subsides in three or four days, when the wound in the globe has become shut off.

3. _Acute iritis_ not infrequently occurs after extraction. It usually comes on about the third day and may be accompanied by hypopyon. It may settle down under atropine, leeching, and dry heat, but may also pa.s.s on into the more chronic form; adhesion of the iris to the capsule, however, frequently results. More rarely the disease may not make its appearance till two or three weeks after the operation (latent sepsis), the patient suffering from recurring attacks of hypopyon. In these cases in which the hypopyon persists, washing out the anterior chamber with peroxide of hydrogen (10 vols. %) and the administration of a vaccine is of service.

4. _Chronic irido-cyc.l.i.tis_ is usually primary, but may occasionally follow an acute attack of iritis. Of all the disastrous complications, this is by far the worst. It may not only destroy the sight of the eye on which the operation has been performed, but may set up sympathetic ophthalmia in the other eye. The eye does not settle down well after the operation, there being usually some prolapse of the iris or capsule into the wound. It remains injected or flushes up on exposure to light. After a time (usually about the end of the third week) kerat.i.tis punctata makes its appearance, and the tension of the eye may become decreased or occasionally increased. The disease may resolve or go on to shrinking of the globe. Energetic treatment with atropine and hot fomentations locally, with the internal administration of iron, is indicated. The administration of staphylococcus vaccine causes only temporary improvement in most instances. In six cases so treated by the author the improvement was only temporary, in spite of the fact that there was a definite local reaction to the vaccine and in two cases the staphylococcus albus was isolated from the fluid in the anterior chamber. If at the end of two months the eye be red and well-marked kerat.i.tis punctata be present, and if the pupil be beginning to be drawn up and the eye shows no tendency to improve, enucleation should be seriously considered; this is especially advisable if the projection of light has become defective, showing that the retina is probably detached. If any signs of sympathetic irritation, such as mistiness of vision, ciliary flush, or photophobia, appear in the eye which has not been operated on, the exciting eye should be enucleated. On the other hand, if well-marked inflammation has developed in the sympathizing eye, which may also be cataractous, and the other eye has a fair amount of vision, it becomes extremely questionable whether it is advisable to enucleate the exciting eye. Every case must be judged on its own merits according to the extent and severity of the disease. In a few cases in which the incarceration of the capsule in the wound leads to a very chronic cyc.l.i.tis, its division with a cutting needle will sometimes lead to subsidence of the inflammation. It is most important that every eye that has been operated on should be examined for the presence of kerat.i.tis punctata, especially before allowing the patient to use the eye or before another operation is performed on it.

5. _Glaucoma_ following extraction occurs as a result of (_a_) soft lens matter blocking the angle of the anterior chamber. As a rule the tension will usually subside under eserine, but evacuation of the anterior chamber (see p. 233) may have to be performed; on the whole the results are satisfactory. (_b_) The incarceration of the capsule in the wound, pulling forward the iris and blocking the angle of the anterior chamber. Division of the lens capsule is usually sufficient to make the tension subside. Failing this, sclerotomy should be performed; the prognosis is not nearly so good when the increased tension is due to this cause.

6. _Striate kerat.i.tis_ usually makes its appearance on the second or third day after operation. The cornea near the line of incision presents a grey striped appearance with the striae arranged at right angles to the wound. Pathologically the condition is due to an infiltration of the deeper layers of the cornea, the striped appearance being caused by wrinkling of Descemet's membrane; the condition probably arises from septic infection. As a rule the affection subsides without giving rise to further trouble, but occasionally local suppuration and even panophthalmitis may follow.

A grey horizontal line about the centre of the cornea is sometimes seen after an eye has been too tightly bandaged; this always disappears when the bandage is removed.

7. _Erythropsia_ (red vision) occasionally follows the extraction of the lens, and is probably due to bleaching of the visual purple following the admission to the eye of an unusual amount of light; it usually disappears in a few weeks.