Chapter IX Crystalline Lens | Operating Microscopes

Anatomy. The lens is a completely transparent body, and in shape resembles an ordinary bi convex optical lens. Its anterior surface is contiguous with the iris and aqueous humor ; its posterior surface, much more convex than the anterior, is in contact with the vitreous body, and lies in the hyaloid fossa.

The crystalline lens is enclosed in a capsule composed of a very elastic, structureless, transparent membrane, which is divisible into an anterior and posterior portion ; the internal surface of the anterior portion is lined with a layer of epithelium. By its capsule the lens is attached to the zonule of Zinn (suspensory ligament), which is merely a continuation of the hyaloid membrane. Near the ciliary processes this ligament divides into two layers, one of which becomes united with the anterior capsule, the other with the posterior. The space between these two layers and the equatorial portion of the capsule is called the canal of Petit. It contains small quantities of fluid.

The lens substance is divisible into nucleus and cortex, the former being composed of the innermost layers of the lens. The cortical substance consists of superimposed layers ; it is softer and more succulent than the nucleus. As age advances, the lens, which in youth is clear like water, becomes yellow and even brown. Simultaneously, its substance becomes more dense, partly because the nucleus increases in size, and partly because the cortical substance becomes less soft.

Histology. The primary elements of the lens are the crystalline fibres. They form elongated hexagonal prisms, and enclose nuclei with nucleoli when they belong to the cortical layer, whilst the latter are wanting in the cells of the interior portion of the lens. The contour of the fibres is smooth in the cortical, irregularly dentilated in the central portion, because the latter, of earlier growth, are compressed by the fibres of more recent formation which proceed from the elongation of the epithelial cells of the capsule, more particularly by those situated near the equator of the lens. The fibres are united by a cementing substance, and form by their union concentric lamellac. Each of these lamelle presents the same arrangement of fibres, which are so grouped that the angle formed by the surfaces of two contiguous fibres is filled by the acute angle of' another fibre. Their extremities arc cut short, the one being oblique, the other round.

On carefully examining the lens, we may find a star shaped figure with three rays on either side ; the superior ray of the anterior surface occupies the vertical meridian, as does also the inferior ray of the posterior surface, so that the figure of the latter seems to be at right angles to the former. These star shaped figures are formed by the termination of the crystalline fibres in the following manner :

A fibre springs from the centre of the lens, and its extremity curves round the equator, ending near it on the posterior surface, a second lens fibre, close to the first, arises a little higher, and as they are of equal length, it terminates beside the other, and a very little farther from the equator ; all the contiguous fibres one after the other are arranged in a similar manner, so that all their extremities are situated in a straight line which forms one of the rays of the figure. A molecular amorphous substance and a system of inter fibrillar canals are found occupying the figure.

The nutrition of the lens is furnished by the zonule of Zinn and the canal of Petit formed by the two lamine of this ligament. As age advances, the lens fibres become dense and hard, and acquire a yellowish tinge. The nucleus is then More easily distinguished from the cortex by its density and more decided yellowish hue. At the same time, the liquid surrounding the lens diminishes.

DISEASES OF THE LENS.

ART. I. Cataract.

A. GENERAL CONSIDERATIONS.

By cataract is meant the more or less complete opacity of the lens. In the early stages it is not always easy to diagnose the presence and extent of a disturbance of the transparency without very minute examination. For this purpose the pupil should be dilated with atropine, and we should make use both of focal illumination and of the ophthalmoscopic (plane) mirror.

To focal illumination, the opacities of the lens seem to be of a grayish or whitish color. In examining old persons, care must be taken not to confound the physiological aspect of the lens with a real opacity ; for at an advanced period of life the lens always reflects a good deal of light, and the nucleus takes on a yellow tint; yet this error is easily detected when the visual acuteness is normal for the patient's age, and when the lens appears transparent to the ophthalmoscope By using the ophthalnosropic mirror alone with a feeble illumination, the slightest opacity can be detected as strie or points which appear black on the red fundus of the eye. Translucent opacities produce the effect of a veil spread over the ophthalmoscopic image.

When the opacity involves a great portion of or the entire lens, it is easily detected at first sight by the grayish or whitish tint of the pupil. Cataract can then be confounded only with plastic deposits in the pupillary field (false cataract) ; but in the latter, the iris is adherent and of an unhealthy appearance, and we look in vain for the dark shadow which the pupillary margin of the iris throws on the lens. The breadth of this shadow is in direct proportion to the distance between the cataract and the iris.

The disturbance of vision varies with the form and exact seat of the cataract. When the opacity begins in the centre, the patient sees better in dark places, and in any condition in which the pupil is dilated; the opposite is the case when the opacity is in the periphery of the lens. During the early stages the patients often complain of myopia and of polyopia; objects appear surrounded with a haze or cloud, and the difficulty of seeing increases imperceptibly and slowly for months or years, till they can no longer distinguish anything more than day and night.

The progress of cataracts is, as a rule, rather slow. Except in a few special forms (congenital, traumatic cataracts, etc.), the lens only becomes opaque at an advanced period of life, and the progress of the disease is more or less inactive; sometimes it seems to come to a standstill. Ultimately, the cataract generally occupies the entire lens, or nearly so; the time which it takes to mature may vary from several months to several years. As a rule, the two eyes are successively attacked.

Etiology. The latest anatomical researches show that senile cataract is preceded by diminution in volume of the lens (PriestleySmith) consequent upon progressive induration. The capsule, being retained by the suspensory ligament, is unable to follow the contraction of the lens substance, and separation of the peripheral layers occurs, associated with the formation of vacuoles in which the fluid of the lens collects, thus giving rise to opacities at first apparent, then real (incipient cataract). At the same time, the cellules of the capsule and the peripheral fibres of the lens, especially those containing vigorous nuclei, begin to multiply and extend into the empty spaces (Becker). Hence, there is a proliferation of epithelial cells in the vicinity of the anterior pole (capsular cataract), the formation of a layer of cells in the internal face of the posterior capsule, and finally the formation of large vesicular cells in the equaturial zone of the lens, and solitary ones on the internal surface of the capsule.

Retrograde metamorphosis of the lens fibres ensues, during which they become atrophied, brittle and opaque, and eventually transformed into molecular detritus, fat, crystals of cholesterine and phosphates. The general and special causes of these changes in the lens are not exactly known. Sometimes they seem to be due to a disturbance of th e general nutrition (diabetes, ergotism, senile marasmus, etc.), sometimes to inflammatory affections in the uveal tract, or in the deep membranes of the eye in general (choroiditis, irido choroiditis, choroido retinitis, etc.) Michel has attributed the origin of cataract to arterio sclerosis; others to renal atrophy (nephritic cataract).

However this may be, cataract is especially a disease of advanced life, and is oftenest found in persons over forty five years of age. Sooner it is secondary to internal diseases of the eye (iritis, choroiditis, separation of the retina), or to general diseases, such as diabetes, or again it may be due to injury of the eye (traumatic cataract). In a certain number of cases, the opacity of the lens appears after recovery from diseases of the skin which have involved a considerable portion of the cutaneous surface. Cataract is also found at birth (congenital cataract), or it may be formed during the first years of life as a consequence of perforation of the cornea.

Treatment. The recorded cases of recovery from cataract by medication may be attributed to an error in diagnosis. Cases of spontaneous recovery of sight are probably cases of dislocation of an opaque lens, or of absorption, without lesion of the capsule or after rupture of the capsule by injury.

Recovery from cataract can only be obtained by surgical interference.

B. VARIETIES OF CATARACT.

Cataracts have always been grouped according as the opacity affects the capsule (capsular cataract), or the lens itself (lenticular cataract), or both structures at the same time (capsulo lenticular cataract).

Lenticular cataract is either partial and stationary (zonular or polar cataract), or total and progressive (senile cortical cataract).

1. Soft or Liquid Cortical Cataract.

The opacity is grayish and like milk ; generally the lens is swollen, and, as a consequence of this increase of volume, the iris is pushed forwards, the pupil is somewhat dilated and sluggish. At a later stage, the contents of the capsule may become completely liquid and remain for a long time in this condition (cystic or sedimentary cataract) or they may undergo a retrograde metamorphosis.

This retrograde metamorphosis consists in the gradual absorption of the liquid portion, and a deposition of calcareous and fatty matter on the capsule. As a consequence of these changes, the volume of the cataract slowly diminishes, and may at length be reduced to the two layers formed by the capsule with the above mentioned deposits (cat. arido silicosa). The anterior chamber is deeper than in the normal condition, the iris is tremulous when the eye moves, or its pupillary margin is adherent to the capsule.

2. Nuclear Cataract. We get from the pupillary field when dilated a grayish or yellowish reflection. With focal illumination we can easily detect the presence of an opacity in the centre of the lens, separated from the capsule by transparent layers (the shadow cast by the iris is very large). To the ophthalmoscope, the opacity sometimes seems to be inconsiderable, but well defined, and the periphery of the lens transparent.

The visual disturbance consists of a diminution of the visual acuteness caused by the lenticular opacity, and of myopia or rather myopic astigmatism. When the pupil is dilated with atropine the vision is improved.

This condition may last for a long time, but the longer it remains the more intense is the color of the cataract ; it becomes brownish red or dark brown ; and finally the cortical substance may also be affected, the cataract becoming complete.

3. Senile Cataract.

This variety, which is by far the most common, begins in the cortical layers nearest to the nucleus. The opacities assume the forin of short stria or irregular patches of a grayish coloration. Simultaneously the nucleus becomes yellowish or brownish. As the cataract develops, the cortical opacities are sometimes in the form of large stria which glisten like an aponeurosis; sometimes the striae are narrow and very white ; at other times no strie can be discerned, the opacity being composed of irregularly disseminated grayish points or patches.

The extent and intensity of the deeper color at the centre gives us some idea of the consistence and extent of the nucleus. The cataract is ripe when all the lens substance has become opaque when it has been for any length of time in this condition, its appearance and consistence may be modified by the condensation of tile cortical masses which condensation sometimes begins before the entire cortex is opaque.

The period occupied by the development of the cataract is very variable, being in some cases a few months, in other cases several years.

Sometimes, in senile cataract, the nucleus is so dark that to simple inspection the pupil appears black. These black cataracts, which can be easily diagnosed with the ophthalmoscope or with focal illumination, are uniformly due to sclerosis of the nucleus. Von Graefe has expressed the opinion that the dark color is due to hematine from old intraocular hemorrhage being carried by the endosmotic current into the lens.

In other cases of senile cataract, the opaque nucleus is hard, and the cortical substance is perfectly liquid (cataract of Morgagni). This variety of cataract is easily diagnosed when the capsule is transparent ; for the nucleus, instead of being found at the centre of the cataract, is seen to have sunk to the bottom of the liquid. It disappears when the patient throws his head backwards, and reappears when he bends forwards.

When the senile cataract is complicated with inflammatory conditions of the deep membranes, we often find calcareous masses on the internal surface of the capsule, while Cie remainder is shrunken. Thus we have the calcareous cataract, distinguished by its chalky appearance. With this there often exists a relaxation of the zonule of Zinn, so that any movement of the eye produces a trembling of the cataract (tremulous cataract).

In other cases we find fatty masses in the cataract, as also cholesterine grains, characterized by their peculiar scintillating reflection. Again some have even observed fibrinous and osseous alterations in the lens elements (Stellwag), the presence of which, however, has been doubted by other observers (Virchow, H. MUller).

C. FORMS OF PARTIAL CATARACT.

Not unfrequently do we find isolated opacities in the lens, as very narrow strie, situated near the periphery of the cortical substance. Such opacities are, as a rule, covered by the iris, and so may exist without causing any disturbance of the vision ; they may be present for a number of years without invading the rest of the lens.

More rarely we find opaque patches in the cortex at some distance from the anterior capsule ; such opacities remain for a long time isolated and circumscribed.

Sometimes also we see in the lens a great number of points or opaque strie in the midst of the transparent cortical substance. This condition, which sensibly disturbs vision, is often stationary for a length of time, or the opacity only makes very slow progress. Complications of the deep membranes of the eye can be diagnosed in some cases, but not in all.

1. Zonular Cataract.

Zonular cataract occupies only a few layers of the lens next to the nucleus, which retains its transparency, as do also the peripheral layers (Fig. 95) On examining the pupil, we find in it a grayish or whitish opacity, which with focal illumination can easily be ascertained to be separated from the iris by a layer of transparent cortical substance.

This form of cataract, which is either congenital or develops during infancy, is most frequently stationary throughout life; progressive cases are characterized by the presence of a few strie or opaque patches in the transparent region of the lens.

The disturbance of vision varies according as the pupil is contracted (as in broad daylight), or dilated (as in a weak light, or after using, atropine). In the first case the patients see very little, and guide, themselves with difficulty. In the second, they see tolerably well, sometimes sufficiently so to read. The necessity of obtaining large retinal images obliges them to bring objects very near their eyes, so, that they appear very myopic; sometimes patients affected with this form of cataract become really myopic. Not unfrequently do we find that such persons are affected with nystagmus.

This variety of cataract is often found in several members of the same family. In most cases, zonular cataract affects both eyes, as in ,rachitic children, where there is aiso some irregularity in the formation of the enamel (Horner). Its mode of development has been connected with cerebral affections accompanied with convulsions (Arlt, Horner).

When the Cataract is stationary, and the vision of the patient sufficient for ordinary occupations, there is no need of operation. When in tile same conditions, tilt' patient call only read easily with a dilated pupil, we may constantly use instillations of atropine, or perform an iridectomy so as to allow luminous rays to enter by the transparent peripheral portions of the lens. When the cataract is very extensive or shows signs of a progressive nature, we may practice discission or extraction.

2. Circumscribed Cataract of the Posterior Cortex Posterior Polar Cataract.

With the ophthalmoscopic mirror we detect opaque bands in the posterior layers of the lens which converge towards its posterior pole. With focal illumination we find that all the anterior portions of the lens are transparent. This form of cataract is most frequently met with in eyes affected with some disease of the deep membranes (choroido retinitis, retinitis pigmentosa)

Posterior polar cataract is in the form of a circumscribed round opacity in the neighborhood of the posterior pole of the lens (perhaps in the vitreous body?). Its position is recognized on ophthalmoscopic examination by the fact that the opacity remains fixed at the centre of the eyeball, no matter how it moves ; it is often found in conjunction with posterior staphyloma and atrophic choroiditis.

3. Capsular Cataract.

Capsular cataract arises, as we have already stated, from the prolification of the epithelial cells of the capsule near the anterior pole. Prolongations sent out by some of these cells penetrate between the epithelial layer and the capsule proper. The epithelium thus detached from the capsule covers up the newly formed tissue either entirely or in part. Occasionally a thin subjacent layer of the capsule becomes detached and raised up with the epithelial layer, so that a capsular cataract produces a true splitting of the capsule (Becker). Under the epithelium are found deposits of finely granulated hyaline in many layers forming a fibrillary tissue. Besides these deposits, calcareous substances may be seen in the lacunae which surround atrophied cells (Becker).

The following is an enumeration of the various forms of capsular cataract:

Central Capsular Cataract. This appears in the middle of the pupillary field as a round, chalky white patch surrounded with a grayish zone. The opacity, as a rule, projects beyond the level of the capsule, either slightly or in the form of a small pyramid, the summit of which is sometimes connected with tile posterior surface of the cornea by it filanientous prolongation (pyramidal cataract).

This capsular opacity is also found on the internal surface of the capsule, that is to say, in the lens itself (H. MUller).

It is found in newly born children ; or it is formed in early life, generally as a consequence of perforations of the cornea. A similar opacity, projecting into the vitreous body, is sometimes found on the posterior capsule. It indicates the insertion of the hyaloid artery, traces of which are seen in certain cases as a thin filament connecting the lens with the optic nerve.

Central capsular cataract may remain throughout life without increasing ; in such cases, no operation should be performed, as luminous rays pass easily between the opacity and the margin of the pupil.
Capsular cataract as an accompaniment of lenticular cataract is always readily recognized by its chalky white appearance, which is due to calcareous incrustations. It is most frequently observed in cataractous lenses that have passed maturity. At other times it is found in eyes that have suffered from choroidal or iritic inflammation ; in the latter case we often find adhesions between the capsule and the pupil (adherent cataract).
Traumatic Cataract Foreign bodies in the lens Any lesion of the eye which produces an opening in the lens capsule exposes the cortical substance to the action of the aqueous humor. The cortical masses become swollen by imbibition, and, assuming a whitish color, escape by the capsular wound and fall into the anterior chamber. The aqueous humor then attacks another portion of the cortical substance, and in this way the entire lens may be absorbed. This is observed in young persons when the capsule has been opened to any extent.

At other times, when the wound has been very small, it may happen that it cicatrizes in a short time, so that we find a grayish opacity which may diminish in extent, or even disappear.

If the capsular opening has been very great, and the accident has happened at twenty five or thirty years of age, there is cause to fear that sudden swelling of the lens which is apt to set up inflammation of the iris. At a more advanced age, the absorption will be more tedious, and inflammation of the iris or choroid is more to be dreaded. In our prognosis, moreover, we must take into account such complications as may arise from injury to other portions of the eye (penetrating wound of the cornea, prolapse or tearing of the iris, intraocular hemorrhages, separation of the retina).

As a result of violent contusions of tile globe of the eye without my lesion of tile capsule, a slow and progressive opacity of the lens has been observe to follow in it short time and may he attribute to defective nutrition (after rupture of the suspensory ligament), or to a severe shock to the lens fibres.

As to the treatment of ordinary traumatic cataract, it is important above everything to obtain and maintain complete dilatation of the pupil with atropine. If we do not succeed in this, or if the swelling of the lens menaces the eye., we must perform an iridectomy, or extract the traumatic cataract with or without iridectomy.

When a foreign body, such as a fragment of iron or stone, is lodged in the lens, it is possible to detect its presence in the early stages before the lens substance has become perfectly opaque. Later, metallic bodies may still be recognized by the brownish color which their oxidation imparts to the surrounding tissue. If, in such circumstances, the cataract is absorbed, the foreign body may remain attached to the capsule, or it may fall into the anterior chamber or behind the iris. In the last case, its presence gives rise to all the dangers of foreign bodies in the eye (irido choroiditis, sympathetic disturbance in the other eye). The same danger naturally exists if the foreign body has pierced the lens and is lodged in the fundus of the eye (sympathetic affections). Whenever a cataractous lens, enclosing a foreign body, requires to be removed by extraction, this should be done in such a way as to extract the foreign body at the same time, lest it should fall into the inaccessible parts of the eye. As a rule, a curette should be introduced behind the foreign body, so as to make sure of it before everything else.

D. THE CONSISTENCE OF CATARACTS (DIAGNOSIS OF).

Having dilated the pupil with atropine, so as to be able to examine the entire extent of the lens, we ascertain the exact coloration and appearance of its surface by focal illumination.

At first we detect the presence of the nucleus by the slightly darker amber or yellow coloration of the central portion of the lens. The intensity of this shade and its extent afford indications as to the hardness, size, and thickness of the nucleus.

The diagnosis of the consistency of the cortical masses is much more difficult. In the first place, some idea of their consistency may be got from the volume of the cataract, in so far as, other things being equal, the cataract is soft when the cortical substance is very considerable and presses the iris forwards ; the anterior chamber is then shallower, and there is an unwonted sluggishness in the movements of the pupil. Yet, these symptoms are only of value where a comparison with the other eye shows that they do not depend on some physiological condition, and where there is no other circurnstance which might account for them such as an increase of intraocular pressure.

The conformation of the cortical masses is of chief importance in the diagnosis of the consistence of a cataract. It is soft when there are large radiating strie, of a bluish or rather grayish color and bright metallic lustre ; between the strie we find less opaque portions of the lens filled with grayish points or patches of an irregular form. When the strie of the cataract are of medium size, they are then, as a rule, very bright; the cortical mass, although soft, has still sufficient consistence to adhere to the nucleus during expulsion. Sometimes the strie are narrow, or of medium size, and whitish, so that if we judged by color alone we should be apt to think the cataractous matter soft. Yet, in such cases it is very cohesive, and the cataract is, as a rule, hard. We may be certain that it is hard when the strie are, narrow, linear and radiating, no matter what may be the color. Let us also add that, in all such cases, other things being equal, the greater the size of the nucleus the more probably is the cataract bard (very coherent). When the cortical substance is striated, and so thin that we can see the dark nucleus more readily than in ordinary circumstances, it indicates that the cataract has undergone a retrograde metamorphosis, and that the cortical mass is adherent and of laminated structure. The space between the anterior capsule and the pupillary margin is in such cases unusually deep, and a greater quantity of light passes by the peripheral portions of the cortical substance, causing the patient to hope that the cataract will be cured spontaneously.

Any conclusion which we may draw as to the consistence of the cortex, depending on the form and color of the strie, cannot be of service in that numerous class of cases in which the strie, are not present. Here the diagnosis of the consistence of the cataract is a matter of the greatest difficulty. Still, some importance may be attached to the following characteristics: If the cortex preserves some of its normal transparency that is to say, if it be not completely. Opaque but present only a diffused whitish or grayish appearance, it may be considered as of normal consistence ; it has not yet become softened. On the other hand, when it has lost all transparency, and is to all appearance perfectly amorphous, without strie or patches, and of a grayish or whitish color, it is most probably liquid. In such cases, we can easily detect the presence of a nucleus, which is no longer at the centre of the cataract, but at the bottom of the liquid cortical masses. The position of the nucleus is thus of importance in judging of the degree of softness of the surrounding cortex. If the cortical substance is grayish, and its surface uniformly (lotted or speckled, we judge of its consistence chiefly by its transparency. If the opacity is almost compete the substance is most likely soft, but at the same time gramous, so that it will readily adhere to the capsule. Often the extraction of the nucleus is attended with difficulty.

When we find between the opaque patches other portions which are still transparent, the consistence is nearly that of the normal lens that is to say, it is gelatinous, and all the more so the more numerous the transparent portions. The presence of narrow strie between the points indicates, on the other band, that the cortical substance is harder.

In concluding these observations on the diagnosis of the consistence of cataracts, we can only repeat the advice which von Graefe so often gave: When we are not perfectly certain as to the consistence of a cataract, it is better to consider it as tolerably coherent, for an incision somewhat too large, if not greatly in excess, endangers the success of the operation less than an extraction rendered difficult by the smallness of the incision.

E. CATARACT OPERATIONS.

General Considerations. Before operating for cataract, it is absolutely necessary to take into account the general condition of the eye which is to be subjected to operation, especially as regards its visual functions, so that after the operation we may not be disappointed by some unforeseen amaurosis. For this purpose, we must carefully examine the tension of the eyeball, the condition of the anterior portions, such as the iris and pupil. We should also inform ourselves as to the state of vision before the cataract supervened, and as to the rapidity with which it was formed; and, most important of all, we should examine the present condition of the visual functions of the cataractous eye.

The examination of the external portions of the eye often affords us very valuable indications. The presence of synechiae, easily discovered, especially when atropine is used, the condition of the iris itself (decoloration, disorganization, atrophy), the hardness or softness of the eyeball compared with its fellow, all give us information as to the nature of the complication. The peculiar appearance of the cataract, and the youth of the patient relatively to the age at which cataract usually supervenes, often induce us to examine most carefully the visual functions, especially if the patient be very myopic, and if we find in the other eye the usual alterations which accompany progressive myopia of a high degree.

These various complications, according to their gravity and according to the influence which they exercise on the visual acuteness, demand from us a corresponding degree of caution in ()ill prognosis; and in cases in which we foresee that there would be no improvement of vision, we must abstain from any operation.

When the only complication present is some affection of the conjunctiva, of the eyelids, or of the lachrymal passages, we should, by appropriate treatment, remove all such sources of irritation before operating.

Should we operate on one eye for cataract whilst the other is completely healthy ? Von Graefe answers this question in the affirmative in those cases in which it is nearly certain that the operation will be successful, as, for example, in cases which are suited for operation by discission or by simple linear extraction ; in other cases it is better to abstain.

When, on the other hand, cataract has begun to be formed in the other eye, or has even become so considerable as to prevent the patient following his usual avocations, we need not hesitate to operate on the eye which was first affected, without waiting till the patient is completely blind.

Should we wait till the cataract is completely mature before operating ?

Experience has shown, it is true, that the cataract comes out of the capsule more easily and more completely when the entire lens substance is involved, and therefore we prefer, as a rule, to wait till this takes place. But it often happens that a long time must elapse before the cataract attains this state of maturity, and we will thus be obliged to defer the operation till the long period of relative immaturity has passed, or, at least, till the patient can no longer use his eyes. In these cases we need not wait till the cataract is completely ripe, but may practise artificial ripening, and select a mode of operating which does not involve any particular element of danger. In cases of congenital cataract, or of cataract occurring at an early period of life, the rule is to operate early, for the defective condition of the vision may easily become at this period of life the source of strabismus or of nystagmus.

Should we operate on both eyes at the same time?

As a rule, we are opposed to this practice, for the reason that the behavior of the patient during the first operation, the progress towards recovery, and the ultimate result, often give very valuable indications as to the manner in which our second operation should be performed. It is only under special circumstances that we decide to operate on both eyes at the same time, such as when the patient cannot be sufficictitly long with us to wait for a second operation, or cannot return to have it done, or expressly desires it.

The honor of having originated the extraction of cataract belongs to Jaques Daviel, who, about 1747 175o, brought forward his method. This process, which required several instruments viz., a lance for puncturing, a two edged knife for enlarging the puncture, and scissors for finishing the flap consisted in making a section in the form of an arc in the corneal border, which detached about the lower twothirds; then, after turning up the flap, the capsule was opened and the lens removed.

Modifications of this method, made by his successors, related at first to the instruments employed ; the knife of Richter appearing in 1773, and that of Beer in 1813 ; and to the flap, the base of which was brought nearer to the horizontal diameter of the cornea (Richter, 1773), and cut in the superior border (Wenzel, Santarelli, 1795). At a much later period the corneal section was brought nearer the sclerocorneal juncture, and the depth of the flap also diminished more or less according to the consistency of the cataract (Jacobson, 1863). Moreover, the operation became gradually surrounded with various precautions. Instead of operating with the patient in a sitting posture, he was made to lie down, and was left in bed until the cicatrization. of the wound was completed. The compressive bandage was improved, so as to immobilize the eyes as much as possible, and the after treatment, following the general progress of knowledge in medicine and surgery, was directed in a more rational manner. Again, Iridotorny (Petit, Maunoir and Carron du Villars, followed by Hasner, Coursserant, Sr., and Chavernac) and Iridectorny were resorted to as means of overcoming the obstacles arising at times from the rigidity of the pupil, and of preventing the dangers resulting from the prolapse of the iris. The latter procedure was at first only adopted in exceptional cases, afterwards in combination with the flap method, either as a preliminary measure (Mooren, 1862) or as a simultaneous operation (Jacobson, 1863). The form of the incision likewise underwent several modifications. A linear incision was substituted for the large flap in cases of cataracts without nuclei (Gibson, 1811, von Graefe, 1852) and, for the other forms with nuclei, an almost linear incision or small flap, cut with a straight knife, in the sclero 6orneal border, combined with iridectomy (von Graefe, 1865).

It should be added that the application of antiseptic principles and the use of cocaine (Koller, 1884) constituted a manifest advancement both in facilitating the operation and in diminishing its dangers.

As for the results obtained by extraction methods Daviel was successful ill 182 Out Of 2o6 operations; von Graefe obtained 90 percent of good ill 16oo cases operated by the (lap method, and by his own method 95 per cent. ; whilst Horner, by means of the latter procedure, combined with the use of antiseptics, obtained 98 per cent.

1. Extraction by Flap Operation.

Indications. Flap extraction is only applicable for cataracts in which the nucleus is hard in proportion to the surrounding cortical substance. We can, therefore, employ it : 1st, in senile cataracts, when there is a hard nucleus of some size, although the cortex may be of normal consistence, softened, or even have passed into the stage of retrograde metamorphosis ; 2d, in young persons, where there is a very large nucleus, no matter what may be its consistence; A in cataracts which have fallen into the anterior chamber.

Preparations. Asept ic precautions being preferable to antiseptic ones, the chief preparation will consist in strict cleanliness for the patient and his surroundings. On the evening preceding the operation, a mild purgative should be prescribed, so that he may be allowed to remain quiet a few days without going to the closet, also a general bath, and repeated bathing of the face with a solution of boracic acid, some of which should be inhaled into the nostrils.

Neither atropine nor eserine should be employed, because the former, by paralyzing the sphincter, invites prolapse of the iris, and the latter induces constriction of the pupil, which makes the passage of the lens more difficult.

During the operation, the patient should recline on the bed which he will occupy during his recovery, so as to avoid unnecessary movement. It is important to be able to place at his disposal the services of a nurse who is thoroughly trained in her duties, for a person who has been operated on must abstain as much as possible from any sudden movement of the head and of the entire body. The patient's room should be easily darkened and aired.

The instruments necessary for this operation are fixation forceps Fig. 6o), a cataract knife with a straight or curved edge (Figs. 96 and ()~), an([ a cystitotne (Fig. 98), or it little pointed hook, which we prefer. All the instruments should be carefully dipped in a solution of boracic acid just before using.

Description of the Operation. The patient, whose healthy eye should be covered by a light bandage, must lie so that the light may fall in a suitable manner on the eye which is to be operated on. The eye and the lids should be cleansed with a solution of sublimate 1 :5000, care being taking that the hands of the operator and of his assistants are absolutely clean. The cornea and the conjunctiva may then be anesthetized by means of cocaine. The head should be firmly fixed, and the eylids separated by an assistant placed, behind the patient.

The first step in the operation is the formation of the flap, either in the superior or inferior aspect of the cornea (superior or inferior keratotomy).

The extraction by superior flap, although more difficult of execution, is to be preferred, as it is less likely to cause escape of vitreous, and allows the superior eyelid after the operation to play the part of a bandage, covering and slightly compressing the wound. We are forced to operate inferiorly ist, when there is an adhesion between the The cataract knife is held between the first three fingers (Fig. 99), so that the index and medius are opposite to the thumb, whilst the superior pupillary margin and the capsule; 2d, when the patient cannot voluntarily turn his eye downwards, which action is necessary for the introduction of the cystitome, and for the natural expulsion of the cataract in the third step of the operation.

(a) Inferior Keratotomy.

1. First Stage : Section of the Cornea. The operator takes the fixation forceps in his left hand, and the cataract knife in his right, holding the cutting edge downwards. With the first he seizes a fold of the conjunctiva very near the internal margin of the cornea, a little above its horizontal diameter. The surgeon has most command over his forceps when he holds them near the extremity of their branches ; and he should take hold of the eyeball at that moment when, following his indications, the patient places his eye in the most suitable position for operation, which, if he adopts our method, is when the patient looks slightly upwards and outwards. As soon as the eye is fixed in this position, the forceps are only required to prevent its displacement, and they should not exercise any dragging influenec or pressure on the eyeball.

Fourth is folded on the palm, and the fifth supports the hand on the bony prominence. The operator first holds the knife in front of the eye, in that position which it should occupy in the organ itself, that isto say, lie should hold the point horizontally with the edge turned downwards, parallel to the plane of the iris. Mien he has assured himself that the diameter of the knife is suitable, and that the extension of his fingers will suffice for the formation of the flap, he pierces the external margin of the cornea with the point of the knife at its junction with the sclerotic, at a point one millimetre beneath the transverse diameter of the cornea.

According to the old method, the flap was made in the corneal substance, consequently the puncture and counter puncture were made at points situated one millimetre within the conjunctival limb. The difference between the old and new methods will be readily understood by comparing Figs. 100 and 101 ' which represent the new (Jacobson's), with Figs. 102 and 103 representing the old.

Having made the puncture, the surgeon rapidly and steadily pushes the point of the knife towards the point which is diametrically opposite to the point of puncture, always keeping the blade of the knife parallel to the anterior surface of the iris. The counter puncture is then made in the cornea by piercing the conjunctival limb with the point of the knife as in the puncture. By further extending the fingers, the flat of the knife is advanced till the inferior border of the pupil is hidden behind the instrument; the fixation forceps are then re moved, and the section is completed by steadily pushing the point of the knife on in its primary direction. The operator must be careful not to lean any weight on the edge of the knife, and the eyeball must be turned towards the temple if there is any danger of wounding the nose.

Shortly before the completion of the flap, when there is only a narrow bridge of the cornea to be cut, the surgeon should stop the forward movement of the knife, and finish the section by withdrawing tile knife as gently as possible. By so doing, he will round off the flap, which, to be regular, should be made entirely in the conjunctival limb As the section approa ches completion, the assistant must let the ACCIDENTS IN INFERIOR lids go gently, and the surgeon, on withdrawing the knife, should direct the patient to shut his eyes, as if to sleet), that is to say, without spasm of the orbicularis.

Accidents which may happen during the first step of the operation. If it happens that the point of puncture has been badly chosen that is to say, above or below the point at which the operator proposed to make it, the operation should be continued, provided the difference is not too great ; the point of counter puncture may be altered so that the flap will possess the necessary dimensions. But if the knife has entered the sclerotic or cornea at such a distance from the conjunctival limb, that a slight turning of the edge forwards or backwards does not bring the incision to the corneal periphery, it is better to withdraw the knife, and for the time being to abstain from any operation. In acting otherwise, we run the risk of making a very irregular flap, either too small or too large, which would be followed by very serious consequences during the second stage of the operation.

If the knife, in crossing the anterior chamber, leaves the plane parallel to the iris, in which it should advance, the point may come in contact with the cornea or, more frequently, with the iris. If the point of the knife should wound the iris immediately after it enters the anterior chamber, the surgeon, if dexterous, may, by a simple change in the inclination of the handle, free it, avoiding the slightest retraction, which would be followed immediately by the escape of the aqueous humor. But if the knife has already gone farther into the iris,.and the aqueous escapes when it is disengaged, it is advisable to withdraw the knife altogether and delay the operation, being ready to begin again when the eye has once more regained a state of rest. When the iris has been punctured near the pupillary margin, it is better to continue the operation without any attempt to disengage the point of the knife. In this way the wounded portion of the iris will be removed, and we may expect to have a greater or less amount of irregularity in the form of the pupil.

The counter puncture may be irregular; it may have entered the cornea too soon, or the sclerotic too late. In the first case, if the position of the counter puncture be not too far from the conjunctival limb, we may, by turning the blade very slightly backwards, cause our incision to run in the limb ; in the second case, we may attain our purpose by directing the edge of the knife slightly forwards. In cases where there is a premature escape of the aqueous humor, it sometimes happens that the iris comes in front of the cutting edge; if the counter puncture has already been made, we must stop for a moment and disengage the iris by pressing very gently on the cornea with the pulp of the index finger ; Own the corneal section must be finished rapidly.

More frequently we cannot avoid cutting a considerable piece of the iris. When on account of this excision there exists an opening in the iris, it should be made to communicate with the pupil, which can be done by dividing the bridge separating them before terminating the operation.

If we have to deal with a very nervous patient who contracts his eyelids firmly, or if we foresee from certain irregularities in the puncture or counter puncture that the flap would be too small, and require ultimately to be enlarged, it is advisable to leave the flap attached, by preserving a narrow bridge at its summit (Desmarres).

This bridge, as we shall again see, is cut after the second stage of the operation. By so doing, we are more likely to avoid prolapse of the iris and of the vitreous body; we may even, if the agitation of the patient demands it, continue the fixation of the eyeball till the incision is enlarged, and even till we have completed the second stage of the operation. The irregularity of the incision may cause the flap to be too small we may then enlarge the corneal incision either with a knife which has a slightly concave blade rounded at the point (Fig. 104), or with a pair of curved scissors (Fig. 105). As a rule, scissors are to be preferred, for with them the incision can be made more rapidly, and without that pressure on the eyeball, which is almost inevitable with the bluntpointed knife.

2. Second Stage: Opening of the Capsule. Having left the patient a few moments at rest, and having wiped the lids with a piece of clean linen, the surgeon directs his assistant to elevate the superior eyelid very carefully, whilst he himself draws down the inferior one, avoiding all pressure on the eyeball.

If the surgeon has not perfect confidence in his assistant, he should hold the superi or lid himself. It should be held very lightly, and let go at the first Contraction of the orbicularis muscle which the patient makes. The operator introduces the cystitome under the flap, elevating it as little as possible, separating the lips of the wound by slight pressure with the neck of the cystitome. The instrument is introduced with its back forwards (see Fig. io6), and the small blade is kept flat against the cornea till the edge is fairly in the pupillary field. Taking great care not to touch the iris, the back of the instrument should be pushed till it comes into proximity with the superior margin of the pupil. On reaching this situation, the surgeon, by a slight rotatory movement of the instrument between his fingers, turns the edge towards the capsule, which he incises by drawing the instrument down till it nearly touches the inferior margin of the pupil.

The cystitome is held flat whilst being withdrawn, and the back of the instrument should be brought out of the wound first, without unnecessarily raising the flap.

As soon as the instrument is clear of the eye, the lids are allowed to close gently.

More than twenty years ago we saw Iarjavay practice the method of opening the capsule with the point of the cataract knife while crossing the anterior chamber in making the corneal flap. When the point arrived opposite the pupil he thrust it into the capsule, withdrew it, and continued the division of the cornea. We shall presently see how this idea has been revived in more recent times.

Accidents which may happen during the second stage.It may happen that on lifting the eyelids to commence the second step in the operation we find a greater or less prolapse of the iris, Without giving heed to this for the moment, we follow exactly the prescribed rules for the introduction of the cystitome and avoid hooking the iris. If it should get caught, we must try to disengage the instrument ; but, if it has been at all dragged upon we prefer to excise the wounded portion.

The incision of t he capsule is sometimes a matter of difficulty, chiefly when the consistency of the membrane is increased as is apt to happen, especially when the cataract has passed the period of maturity ; it then becomes necessary to exercise slight pressure with the cutting edge of the cystitome on the capsule. This naturally requires great delicacy of manipulation, which practice alone can give, as there is a danger that the surgeon may rupture the hyaloid membrane and cause a prolapse of the vitreous. ' Moreover, this pressure must cease as soon as the small blade of the cystitome has entered the cataractous mass, and it is safer even to hold the instrument almost flat whilst continuing the incision of the capsule ; if this precaution be neglected, we may have a dislocation of the lens. If we are not quite sure that the capsule is sufficiently divided, we must repeat the incision in the manner indicated, before withdrawing the cystitome from the eye. Complete opening of the capsule is generally indicated by a slight forward movement of the lens with a perceptible dilatation of the pupil and a slight rising of the flap, which may be taken advantage of in removing the instrument.

When the summit of the flap has been left attached by a bridge of corneal tissue, we may advantageously use Desmarres' cystitome in opening the capsule, for it is provided with a cutting edge, with which we may, immediately after the rupture of the capsule, complete the section of the cornea. If necessary, the fixation of the eye may then be continued during this stage of the operation ; but if we wish to prevent the sudden evacuation of the cataract, it is well to remove the fixation forceps as soon as the knife completes the corneal section. This should be done as slowly as possible.

3. Third Stage : Extraction of the Cataract. The surgeon, gently raising the superior lid with the thumb of his left hand, draws the inferior lid slightly downwards with the index and middle fingers of his right hand, and directs the patient to look up ; these movements are often sufficient to cause the cataract to escape from the. eye.

When the spontaneous muscular contractions of the patient are not sufficient to start the lens, the surgeon can, with his fingers placed as indicated, easily make slight pressure through the eyelids on the part corresponding to the superior margin n of the lens, whilst he also makes slight counter pressure below on the sclerotic. (Fig. 109) Such pressure must be made very gently, and should continue, gradually increasing, till the greatest diameter of the lens crosses the pupil ; it should then diminish, entirely ceasing when the inferior margin of the lens presents itself in the wound. If these manipulations are not careful in removing the cataract, we" must seek for the source of re, which may be an insufficient opening of the capsule, a contract of the pupil, or some fault in the flap. In the first case, it is sary to re introduce the cystitoryie ; in the second, whatever may a origin of the papillary contraction, we must abstain from any geritte(i pressure on the eyeball, as prolapse of the vitreous body apt to occur. It is better at once to proceed to the excision of a portion of the iris, which, as a rule, makes the expulsion of the cataract very easy. Instead of iridectomy, Coursserant, Sr., more than twenty years ago, made an incision in the iris with scissors, from the ciliary border towards the pupil, as Petit, Maunoir and others had previously advocated. Chavernac proposes a similar incision in the pupillary border, when the expulsion of the lens is impeded by the iris. If, notwithstanding the light pressure exercised on the eyeFIG. ball through the lids, there is still delay, it then becomes 8 necessary to attempt extraction with Critchett's curette (Fig. I I o) or a wire loop introduced behind the iris.

These instruments should also be used when, from some excessive pressure on the part of the assistant or of the patient, or some peculiarity of the eye which is being operated on, there is an escape of vitreous before the lens is expelled. In such circumstances it is of great importance to proceed without loss of time, and in such a manner as will insure the extraction of the cataract. We should therefore use the wireloop or the curette.

4. Fourth Stage: Clearing away of Debris from the Wound. When in a normal operation the third step has ended in a successful expulsion of the cataractous lens, and when we have allowed the lids to close, it remains for us, after giving the patient a short interval of repose, to begin the fourth and last step of the operation, that is, to clear the pupil and the wound of such cataractous debris as they may contain. Lastly, we must see that the condition of the pupil is normal, and the coaptation of the flap perfect.

The superior eyelid being closed, we begin by gently rubbing it with the pal mar aspect of the thumb in a direction concentric with the margin of the cornea. By so doing, we collect the cortical masses retained behind the iris at the centre of the pupil. We then direct these masses towards eyelid the summit of the flap by lightly sliding the superior over the cornea from above downwards.

After the complete expulsion of the cortical masses, if we find that there are capsular opacities, we try to remove them by means of a small hook, or with curved forceps with fine teeth (Fig. i I I), or with Graefe's capsular forceps (Fig. 112). The blades of the forceps are closed, and introduced along the posterior surface of the cornea so as not to wound the iris. the opaque portion is then taken hold of by the forceps withoutincluding the hyaloid membrane Tile extraction of the opaque capsule is often followed by a loss Of vitreous.

The pupil, when it is properly cleared, is of a deep black.

Our attention should then be directed to the proper coaptation of the flap ; if it be insufficient we must try to ascertain the cause, which may be either the presence of cortical matter between the lips of the wound, or a prolapse of the iris; or, again, a hernia of the vitreous.

To free the wound of cortical substance, it generally suffices to wait a little till the aqueous humor has again collected, and then to separate the lips of the wound slightly, so that the liquid current may wash out the cataractous debris; if not, we may use Daviel's curette (Fig. io8), or a tortoise shell spatula, which is very gently slid along the sclerotic margin of the wound, beginning at the nasal side.

If a prolapse of the iris prevents the coaptation of the flap, we should endeavor to reduce it by gentle friction across the lid, or by means of a spatula, with which we push the iris back into the anterior chamber. When the pupil regains its usual form and position, a drop of eserine may be instilled. But, if the pupillary border be displaced. in the direction of the wound, and especially if the prolapse be persistent, we must not hesitate to practice iridectomy.

The flap may again be raised by the vitreous body, which, enclosed in the hyaloid membrane, presents itself between the edges of the wound. It suffices, then, to open the membrane by a small cut with a pair of scissors ; a few drops of vitreous escape, and the hernia of the hyaloid having disappeared the coaptation of the lips of tile wound becomes more perfect.

In cases where a badly formed flap prevents the perfect coaptation of the margins of (lie wound a bandage May, as far as possible, serve to remedy the defect, and to diminish the chance of an unfavorable result from this state of matters. Sometimes, after the extraction of the lens, the cornea seems to be sunk down, folded, or even deeply depressed. The reproduction of the aqueous may establish its normal curvature; but, in other cases, this defect persists till a bandage is applied, which ought to be made more compressive than usual.

We merely mention not having tried it ourselves or seen it put in practice by others Hasner's proposal to puncture, in cases of corneal collapse, the vitreous body, the fluid from which then fills the anterior chamber, and may thus cause a more perfect coaptation of the flap.

When the surgeon has found that the position of the flap is good, he may, to reassure the patient and raise his courage, make him count fingers or show him a few objects which are not too brilliant. During such examination, which must be of short duration, it is advisable to shield the eye from too intense a light by the hand used as a screen. At last the eye and the lids have to be washed carefully with the antiseptic solutions.

Dressing and Treatment after Flap Extraction. The dressing consists of the application of a compressive bandage on the eye which has been operated on ; the other is also closed, and the room somewhat darkened. Great. care must be taken that the dressing fulfils the condition of steadying the globe as much as possible without annoying the patient. We may then leave it in position forty eight hours undisturbed, which we consider a great advantage in the process of repair. The patient, attended to if possible by a thoroughly trained nurse, should be kept absolutely at rest for the first twenty four hours, during which time he should. get only such nourishment as does not require mastication. However, there are some patients who become restless in bed during the daytime, and who will sit quietly in an arm chair. In such cases we do not hesitate to allow them to do so.

If there be any reason to fear sleeplessness, we administer a subcutaneous injection of morphia, or a dose of chloral hydrate. The second day after the operation we change the bandage, and if we find everything going on well it may remain during the next forty eight hours. On the fifth and sixth days we remove the bandage in the morning, at each dressing paying strict attention to cleanliness, and bathing the eye with a solution of sublimate if required. Even after that interval, we still use the bandage at night, whilst a simple knitted bandage is used during the day. After eight days, if the progress of the recovery has been uninterrupted, the patient begins to wear a loose shade of black silk, then dark spectacles, with which he may be able to go out about the beginning of the third week, according to circumstances especially according to the irritability of the eye to light.

(b) Superior Keratotomy, or Superior Section.

In this method, the fixation forceps take hold of the conjunctiva at a point beneath the horizontal diameter of the cornea, the knife is held with its edge upwards, and the flap is made according to the principles already indicated. The second step is much more difficult than with the inferior flap, because the natural disposition of the eye is to turn upwards. It is therefore better, especially if the operator is somewhat inexperienced, when this rnethod is adopted, and when the patient is agitated, to preNerve a small bridge of corneal or conjunctival tissue at the summit of the flap Fig. 113), so that the capsule may be divided whilst the eye kept fixed.

In the third step, the hands are placed exactly in the same. position as for extraction of the lens by inferior keratotomy ; but the principal pressure should naturally be made on the inferior margin of the lens, with the index and middle fingers of the right band.

All the other manipulations are the same as those which are made in inferior keratotomy. It is easy to understand that the expulsion of the cortical masses becomes much more difficult, and iridectomy, in cases of prolapsed iris, almost impossible, if the patient cannot of his own accord turn his eye downwards.

Accidents which may happen after Extraction by Flap Operation. The pain which the patient feels during the hours which immediately succeed the operation need cause us no alarm ; in old persons this symptom seems to be even more favorable than complete insensibility of the organ which has undergone the operation. If the pain continues till the evening, and is likely to produce insomnia, we give a subcutaneous injection of morphia, or a dose of chloral, as already indicated.

If the patient, the day after the operation, or at a later period, complain of pain in the eye, or in the forehead and head on the side of the eye, which has been operated on, it is necessary to seek for the cause of the pain by closely examining the organ. This examination is best made by the light of an ordinary candle, which may be very advan¬tageously used for direct illumination, or the light may be concen¬trated with a convex glass on the separate points which we wish toinspect.

In a certain number of cases, we find an imperfect coaptation of the flap, the margin of which may already be the seat of an infiltration of a yellow or white color with grayish striation, which extends towards the centre of the cornea. As a rule, this condition of matters may be diagnosed before the lids are opened by a slight swelling of the upper eyelid, especially at the inner canthus, by a more copiouls secretion of tears, which may also be detected by the greater or less degree of moistness of the linen placed next to the eye, under the bandage.The best means of arresting this exudation consists in the immediate application of the electro cautery to the affected spots. To this ad¬vice, given by Abadie, we owe the preservation of more than one eye. The application of ice cold compresses to the eye, or of leeches to its neighborhood, should be firmly rejected, as being in reality dangerous.

According to the effect produced we repeat the cauterization, and apply the compressed bandage in the intervals. At each dressing, the conjunctival sac and the region of the wound are carefully cleansed with the sublimate solution. The pain is most effectively checked with suhcutancous injections of morphia.

In other cases, particularly when blennorrhea or the laclirymal sac is present and (more rarely observe) when the patient is in all advanced state of senile marasmus, we find, generally from twenty four to forty eight hours after the operation, that the superior eyelid is swollen and shining; this is ccompanied with a yellowish or dirty grayish nearly liquid discharge, traces of which are found on the linen of the bandage ; the matter is also accumulated in the internal angle of the eye. On opening the lids, we notice that the saine matter mixed with tears escapes; we find conjunctival chemosis and a general infiltration of the cornea, which is most pronounced in the flap, where by degrees it gives place to a profuse suppuration, which spreads over the entire cornea. We may be able to counteract this condition by cauterizations, and by active treatment with sublimate; but when this diffuse suppuration is thoroughly established, neither remedies nor bandages are of any further use. Hot fornentations and, at a later stage, cataplasms can alone help to ease the pain.

Apart from these misfortunes which may originate in the flap, there are other complications which begin in the iris. Ordinarily they do not appear till a few days after the operation, except in cases where they are due to cortical masses retained in the eye. The patients coinplain of severe periorbital pain in the early stages of the disease ; there is lacbrymation, with deep injection and sometimes slight serous chemosis. The aqueous humor is muddy and the pupil begins to contract. In such circumstances we attach the greatest impDrtance to the instillation of duboisine ; we use a very strong solution, instilling one drop every five minutes for half an hour; we repeat these instillations several times a day. Subcutaneous injections of morpbia check the pain and procure the sleep which is so beneficial in such affections. At the same time, we order mercurial frictions, with fractional doses of calomel internally. The application of leeches before or behind the ear on the same side as the operated eye has also a good effect, when we are not dealing with a too enfeebled constitution.

When the iritis supervenes at the time of cicatrization, and seems to be caused by a prolapse of the iris, we may act according to circumstances. If there is only a slight displacement of the pupillary border, indicating that the iris has been drawn into the corneal wound, we persist in the application of a compressive bandage, which is undoubtedly the best means of promoting the formation of the cicatrix. In case of an actual prolapse it becomes necessary to excise it, in order to clear the wound and avoid, at the same time, these changes in the curvature of the cornea which almost always result from the enclosure of a portion of the iris ill the wound. Cauterization of the iritic hernia is not advantageous under these conditions.

The general regimen as also the general treatment of suchaccidents, must depend ill :111 cases oil tile constitution of tile patients oil their age, and on their temperament. To full blooded persons we give mild laxatives and non stimulating drinks ; for old and weak patients we order nourishing food, wine, quinine, etc.

2. Flap Extraction Combined with Iridectomy.

At first iridectomy was only performed on account of synechia, or when the iris was perceptibly contused or even pushed between the edges of the wound (von Graefe). Later, this combination of iridectomy with flap extraction came to be preferred in every case where there was occasion to use very special precautions (Mooren) ; for example, when a person bad already lost one eye in consequence of iritis after a cataract operation, or when, after the instillation of atropine, the slow or imperfect dilatation of the pupil showed, previous to the operation, a marked predisposition of the iris to inflammation. Afterwards, it was proposed always to perform iridectomy in conjunction with flap extraction, it being thought that the greater number of good results should outweigh the inconvenience arising from the deformity in the pupil (Jacobson).

Iridectomy was combined with flap extraction in two different ways: sometimes the iridectomy was performed several weeks (fifteen days to six weeks) before the extraction of the cataract (Mooren) ; sometinies both operations were performed at the same time (Jacobson).

Jacobson, who practiced as a general method flap extraction combined with iridectomy, made the flap entirely in the conjunctival limb at the inferior aspect of the cornea. To him belongs the merit of having, by his method, directed the attention of surgeons to the great advantages, as concerns the recovery of the eye, to be derived from a peripheral section, advantages which are probably due to several causes. These causes are ist, the highly vascular nature of the conjunctival limb, which also explains the well known fact that lesions and ulcerations of the cornea heal the more readily the nearer they are to the corneal margin ; 2d, the possibility of excising the iris to its ciliary insertion when the section is peripheral by so doing, we prevent the cortical masses from lodging behind the iris and becoming a source of irritation ; A having made the iridectomy, the possibility of opening the capsule with the cystitome in the neighborhood of the lens margin this condition especially affords an explanation of the complete expulsion of the cortical substance ; 4th, the more easy expulsion of the cataract, the border of which is found in the immediate neighborhood of the wound, and moves in its normal position, without any rotation round its axis.

On the other hand, the peripheral flap predisposes much more than does the classical flap to prolapse of the vitreous, and this circumstance compelled Jacobson habitually to use complete general anesthesia during the operation.

We must admit that the statistics published by the author of this method undoubtedly contained a greater number of favorable results than had hitherto been obtained by flap extraction ; but it must also be added, that the notable enlargement of the pupil, caused by the inferior iridectomy, exercises a most prejudicial influence on the toleration of variations in the illumination. It produces also a most uncomfortable dazzling, and increases the patient's difficulty in guiding himself, rendering it more difficult to distinguish objects at different distances without change of glasses.

As regards the execution of flap extraction combined with iridectoray, it only differs from the classical operation by the introduction, between the first and second steps, of the excision of a portion of the iris. If we prefer to maintain the fixation of the eye during the iridectomy, it is necessary to leave a bridge of corneal tissue at the summit of the flap.

The blood which sometimes escapes after the iridectomy, and which may conceal the pupil, is easily evacuated by pressing the superior eyelid very gently on the eye. If, notwithstanding these manipulations, some blood remain in the anterior chamber, we must open the capsule according to the ordinary method, and, as soon as the cortical mass enters the capsular opening, we will find the blood retract to the periphery of the anterior chamber. The dressing, as also the after treatment, does not differ from that prescribed after the classical extraction.

3. Cataract Extraction by Linear Incision.

General Considerations. The dangers of flap extraction, which arise from an incision involving almost the half of the circumference of the cornea, and from defective coaptation of the flap, naturallv led to the idea of restricting as much as possible the section destined to give passage to the cataract. On the other hand, it could not be overlooked that the expulsion of the lens through a wound too small to allow it to pass easily, must cause contusion of the margins of the wound and straining of its angles. Daily experience, indeed, warns us that we must carefully avoid a tedious extraction, if we do not wish to run serious risks.

Consequently, the extent of the incision should be in direct proportion to the consistence and size of the cataract. It is one of the greatest merits of von Graefe to have established linear extraction on its true basis, and to have restricted its use to certain well defined groups of cataract cases.

(a) Simple Linear Extraction.

Indications. This method is suitable for entirely soft or liquid cataracts, which may have developed spontaneously, or may be the result of an injury of the lens in a young person.

This variety of cataract is almost exclusively observed in children and in young adults up to the age of twenty or twenty five. At a more advanced age it is sometimes developed as a consequence of deep seated disease of the eye, and requires a careful examination of the functional state before decision as to the operation. If such examination reveals the absence of the visual faculty, the operation for cataract can have no other end than to give the pupil its normal black reflexion.

The extraction of a capsular opacity through a linear incision in the cornea is only advisable in cases where there is no direct continuity between the capsular fragments and the margin of the pupil ; even then the surgeon must use every precaution, and relinquish the attempt if slight traction does not draw out the opacity. Prolonged traction on the iris or on the ciliary processes frequently becomes the source of iritis or irido cylitis, which may end in the loss of the eye. We shall indicate in a future chapter the method which is suitable for such cases.
(See Chap. on Discission.)

Description of the Operation. The instruments necessary for the operation are 1st, a spring speculum for the lids (Fig. 59); 2d, fixation forceps (Fig. 6o); A a triangular keratome (Fig. 61) ; 4th, von Graefe's cystitome (Fig. 98); 5th, a large curette (Fig. 114).

There may also be at hand a probe pointed knife (Fig. 115) to enlarge the wound if necessary, and iris forceps and curved scissors, in case it is required to excise a prolapsed iris.

First Step: Section of the Cornea. The patient being placed on a couch in the ordinary manner, and the speculum introduced under the eyelids, without separating them to a needless extent, the surgeon takes hold of a fold of the conjunctiva, near the internal mar¬gin of the cornea, and at the nasal extremity of its horizontal diameter (Fig. x16); he then proceeds to make his incision in the following manner: The triangular keratome being directed towards the fixation forceps, the surgeon rests the point of the instrument, held flatly, on the point of the cornea which is situated in the horizontal diameter at 2 millimetres from the scleral ring. Having made a slight depression at this point, he penetrates the anterior chamber, and pushes the point of the instrument, parallel with the plane of the iris, right on towards the fixation forceps (Fig. 116), till the wound is about 6 or 7 milli¬metres in lenath. Then, lowering the handle of the instrument towards the patient's temple, so that the point is brought nearer to the posterior surface of the cornea whilst the aqueous humor is escaping, he withdraws the instrument gently, at the same time enlarging the internal wound. This enlargement of the internal wound, which is of importance for the regularity of the opening, is easily managed by holding the handle of the instrument towards the patient's cheek when we wish to enlarge the superior angle of the wound, or towards the forehead when we wish to enlarge the wound at its inferior angle.

Second Step: Rupture (Discission) of the Capsule. Without removing the fixation forceps, the cystitome is now taken, and its small blade is held flat against the external lip of the wound, which is gently depressed, and the instrument is introduced, with the back of the blase forwards, into the anterior chamber along the posterior sur Of the cornea ( 1 19. 1 IT). On reaching the internal papillary margin, the edge of the cystitome is turned towards the capsule, which is ruptured by withdrawing the instrument till its point is only a short distance from the external margin of the pupil. If a sufficiently large opening in the capsule has thus been obtained, the blade of the instrument is again held horizontally, the back being now turned towards the wound, and, holding it against the posterior surface of the cornea, it is removed from the anterior chamber, so that the point of the cystitome leaves the wound last.

Third Step: Extraction of the Cataract. Still keeping the eye fixed, the back of a large curette is gently pressed against the external lip of the incision, so as to make the wound gape, and at the same time gentle pressure is made with the fixation forceps on the internal side of the ball (Fig. 118). The lens emulsion speedily escapes between the lips of the wound, which is allowed to close by removing the curette as soon as the pupil regains its usual deep black appearance.

All that is then required is to remove the fixation forceps and the lid speculum. When all the cataract does not come completely out, we allow the lids to close, and, while lightly rubbing the superior lid over the periphery of the cornea, so as to bring the lens fragments into the pupil, we wait patiently till a portion of the aqueous is re secreted. The debris is then generally washed out by the aqueous humor which escapes through the wound. These manipulations may be repeated several times at short intervals, and they are much to be preferred to tile introduction of a curette into the anterior chamber Moreover, the retention of a small portion of a soft cataract in the anterior chamber does not materially influence the result of the operation, for such fragments are speedily absorbed in young persons. Nevertheless, for reasons indicated in speaking of flap extraction, we prefer to evacuate the lens masses as completely as possible by exercising a little patience; and, by repeating the prescribed manipulations several times, we almost always obtain the desired result.

Having thus finished the operation, we hold a moist sponge for a few seconds on the closed lids, and then apply a pressure bandage, as after flap extraction.

The secondary treatment is of the most simple description. During the first two days we leave the bandage in position, and then change it every morning, instilling a drop of atropine at each dressing. After the lapse of a few days, while continuing the instillation of atropine, we replace the compress and bandage by a black silk bandage worn loosely before the eye, and very gradually accustom the patient to daylight. We may allow him to go out as soon as all traces of irritation have disappeared from the operated eye, generally in about a week from the operation, making him still wear, however, shell shaped spectacles of smoked glass.

Accidents which may occur during and after the operation. When there is a prolapse of the iris, we attempt its reduction by lightly rubbing the superior lid over the cornea, or by pushing it back by means of a spatula, Nevertheless, if the reduction is not easily made, or if it will not remain in place, rather than run the risk of occasioning a serious complication in an operation usually almost harmless, we unhesitatingly excise the prolapsed portion.

This small iridectomy does not considerably increase the size of the pupil, for it can only remove the pupillary margin of the iris to the level of the internal lip of the wound.

Prolapse of the vitreous is an accident of great rarity ; it may be caused by the cystitome, when it penetrates directly through a thin cataract into the vitreous body, or by misdirected pressure on the eyeball. Should this accident occur before the expulsion of the cataract, we must at once extract the lens by introducing a curette into the eye. Apart from the prolapse causing the expulsion to be more difficult and, as a rule, less complete, there is the danger of a portion of the vitreous being caught in the wound. In that case, we apply a tight fitting compress and bandage for several days. Notwithstanding this precaution' we sometimes find an irritation of the lips of the wound, and the formation of a cicatrix much more apparent than the almost imperceptible whitish line which ordinarily indicates the situation of the linear incision in the cornea.

If the surgeon has made an error in his diagnosis as to the consistency of the cataract, and if he recognizes, after making his incision, the presence of a nucleus of some size, he must enlarge the wound with a blunt pointed knife and extract the nucleus by means of a curette or Weber's hook.

When, after the expulsion of the cataract, there remain capsular opacities in the pupillary field, they may be easily removed by introducing through the corneal wound a pair of forceps or a small hook.

If we are dealing with a non adherent shrunken capsular cataract, after the corneal incision we introduce into the anterior chamber a pair of capsular forceps or a sharp hook, with which we take hold of the cataract and draw it out. Even when this form of cataract is in part adherent (at most for a third of its pupillary margill), we can make the corneal section just above the adherent portion, take hold of the cataract with a sharp book near the opposite pupillary margin, extract it and cut off the portion of iris drawn out quite close to the opening in the cornea.

We rarely have occasion to see after a normal operation any serious accident during the period of convalescence. When there is secondary iritis, we should follow the saine course as when it occurs after the flap operation.

Extraction by Suction. We should mention here the extraction of cataract by suction, the best instrument for which is Bowman's suction needle. In order to introduce this needle, a small linear incision in the cornea, and the opening of the capsule, are required. As this operation can only be applied to soft or nearly liquid cataracts, which may be easily extracted by the usual linear method, the use of the suction needle seems to be superfluous.

(b) Linear Extraction Combined with Iridectomy.

General Considerations. The easy and rapid recovery after linear sections of the cornea, compared with the dangers to which the eye was exposed from the flap opening, naturally led to a desire of being able to use the linear method in such varieties of cataract as were reserved for flap extraction. The first attempts made for the purpose of extending linear extraction to hard cataracts with a large consistent nucleus, very soon showed the dangers which were run in forcing the cataract out by a passage which is too narrow for it.

It was found that the violent contusion of the iris and of the margins of the wound, which results from the disproportion between the size and consistence of the cataract and the dimensions of the wound, seriously compromised the recovery ; and the results of the method were such that linear extraction was restricted by all judicious and conscientious observers to soft cataracts.

The attention of those who continued to study the question was naturally brought to bear on the possibility of enlarging the passage, and of helping the expulsion of a cataract with a nucleus, either by previous trituration (Desmarres), or by using traction instruments. With this object in view, the extent of the linear incision was first increased till it embraced a quarter of the corneal circumference ; the principle of a linear wound being thus, to some extent, abandoned, whilst the incision retained the form of a slit, whose margins tended to close accurately as soon as the lens had passed. To this enlargement of the corneal wound situated near the sclerotic margin, there was added the excision of a portion of the iris (von Graefe), in order to protect that membrane from the dangers of contusion, and to increase the size of the pupillary opening, which by its contraction might readily prevent the application of a suitable curette (larger, flatter, and provided with a sharper edge than Daviel's coterie) which is used to draw out the cataract. Yet von Graefe, who was the first to propose linear extraction combined with iridectomy and the use of the curette (see Archiv fur Ophthal., 1859, v. i, P. 158), only wished to use it in certain varieties of cataract, where the nucleus is of medium size and the cortical substance soft and abundant. He proposed to substitute this method for flap extraction, especially where the latter, from conditions of the general health, seemed dangerous, as when there was senile marasmus, chronic catarrh of the broncbi, asthma, or some other affection which would prevent the patient from being confined to bed for any length of time. He also recommended this method for soft adherent cataracts, and for such as contain a foreign body.

Waldau attempted to generalize the method by comprising as suitable cases senile cataracts. He had a traction instrument made, which resembled a large curette with edges. This, being introducedbehind the nucleus, in reality forced a passage for the hardest cataracts through a linear incision at the external margin of the cornea. Still, the results obtained by this proceeding as a general method were not sufficiently fortunate to allow him to abandon advantageously the classical method of flap extraction.

Linear extraction combined with iridectomy and extraction of the cataract with a curette, underwent important modifications in Critchett's hands. He increased the dimensions of the incision (to one third of the corneal circumference), and made it at the superior aspect (see Fig. i 19), so that the deformity of the pupil from the iridectomy might he hidden by the superior eyelid. This method it is true, greatly reduced the inconvenience of the enlarge pupil. Moreover, he replaced Waldau's curette by another, which was much thinner was perfectly flat, and had a margin only at its extremity. But notwithstanding these important modifications which distinguish the English method (spoon extraction) from that of Waldau, it could not pretend to replace in a general manner flap extraction. It is true that in the English method the after treatment is much shorter and more simple, and the number of completely successful operations was almost the same as with flap extraction ; but the number of imperfect recoveries was much greater.

Consequently, linear extraction combined with iridectomy at that period could be considered only as an exceptional method, applicable to certain forms of cataract. There was thus no reason for abandoning the classical method, in vogue for such a number of years and on such a large scale, for this new method, which, moreover, demanded that the surgeon should familiarize himself with manipulations to which he was not accustomed, and be provided against unforeseen dangers.

Such was the state of the question when von Graefe was led, by continual study and close investigation, to propose a new method, which, realizing more perfectly the advantages of the linear extraction, and the easy expolsion of the cataract, was immediately put into practice on a large scale by the author himself, as also by other surgeons, so that, in a relatively short time, this new method gained the favor of all those who were able to assure themselves of the great advantages to be reaped by the fortunate combination 'suggested by the Berlin professor.

We may enumerate the advantages of this method under the following heads:

1. The situation and form of the wound. The incision is as nearly linear as the necessary extent of the wound permits ; it is mode in the scleral limb, and is situated at the spot to which the lens will come as soon as the aqueous humor escapes. The cataract, after the excision of the iris, will come out directly, without the rotation forwards which is necessary when the wound is situated in the cornea itself. This peripheral situation, besides, gives to the operation a less dangerous character; for the observation of injuries and of operations had proved that wounds at the corneo sclerotic margin are in a more favorable condition for cicatrization, and present fewer dangers during the period of recovery, than those made in the cornea itself.

2. The excision of the iris, after the peripheral section of the cornea, allows the capsule to be opened at the equator of the cataract, thus affording an easier expulsion of the lens, and a more complete removal of the cortical substance, which separates from the nucleus as it passes through the corneal wound. In fact, this lenticular dibris remaining in the eye is usually hidden behind the iris.

3. The cataract readily slips through this incision without the introduction of a traction instrument. This advantage removes the drawback which was justly attributed to curette extraction viz., the necessity of introducing a curette into the eyeball and the risk occasioned thereby.

4. The wound may be covered with a conjunctival flap, which circumstance, in the opinion of von Graefe and of other observers (e.g., Arlt), promotes the rapidity of the cure, if it has not a considerable influence in the ultimate result of the operation. Again, the form of the wound allows, without the slightest danger, all those manipulations which are of use in expelling as completely as possible the cortical substance.

These advantages, and, what is of more value than all theoretical considerations, the statistics of the results, incontestibly showed the superiority of von Graefe's method over all others. We shall, therefore, give a description of his method in all its details.

(c) Peripheral Linear Extraction (von Graefe's Method).

Indications. Li near extraction combined with iridectomy was already used in cases of' cataract Where the nucleus was relatively small and the thick cortical masses soft. Von Graefe's method, which gave an easy exit even to the largest and hardest cataracts without the introduction of a traction instrument, has extended the primitive use of the linear method to all senile cataracts. It may,, therefore, be adopted instead of the classic flap extraction.

Description of Von Graefe's Operation. We will not repeat here the necessity of cleanliness and antiseptic precautions indicated in a preceding chapter. In von Graefe's operation, atropine is not instilled into the eye, for, as we have seen, the margins of the coloboma re enter the anterior chamber much more easily after the iridectomy, when it is not used. We thus always avoid all difficulty with the iris.

The instruments necessary for the operation are: A lid speculum without a spring, which opens and closes with a screw (Fig. 120) ;Waidau's fixation forceps, with a catch (Fig. 12 1) a von Graefe's knife ( Fig. 1 22 ) ; iris forceps, straight or curved Figs. 123, 124) ;a pair of bent scissors (Fig. 125), or Wecker's scissors forcep*s; a curved cystitome (Fig. 126) ; a caoutchouc curette (von Graefe) (Fig. 127), and a tortoise shell spatula.

First Step : Peripheral Section. Having inserted the speculum under the eyelids, the surgeon steadies the eyeball, and draws it gently downwards by taking hold with the fixation forceps of a fold of the conjunctiva immediately beneath the inferior border of the cornea. Holding the knife with the edge upwards, he punctures the sclerotic at a point situated about I millimetre from the corneal margin, and 2 millimetres below the tangent to its summit. The point of the knife, on entering the anterior chamber, is at first directed towards the centre of the cornea, till the instrument has advanced 7 or 8 millimetres ; then, lowering the handle of the instrument, the point is raked so as to be brought under the sclerotic margin near the point of counter pu nct tire (Fig. 128).

This point should be symmetrical to the point of puncturc, that is to say, at the same distance from the margin. and from the tangent to counter puncture is the summit of the cornea: we know that the made when the point of the knife no longer finds any resistance. The edge, which till now has been directed upwards, is then turned obliquely forwards towards the corneal margin, and a sawing movement is imparted to the instrument by making it penetrate to its entire extent and then withdrawing it. This last movement, as a rule, suffices to effect the section of the margin of the sclerotic ; if not, the sawing movement is repeated till the knife, having cut the last strand of sclerotic tissue,, is free and mobile beneath the conjunctiva (dotted line, Fig. 128). To cut the conjunctival tissue, the edge of the knife is directed forwards, or even a little upwards if a conjunctival flap is wanted.

Many surgeons, and we among their number, do not like the conjunctival flap, and never make the incision in the sclerotic. We are in the habit of making our incision in the corneal margin, at the junction of that membrane with the sclerotic, and the puncture and counterpuncture are made 3 millimetres below the tangent to the summit of the cornea (Fig. 1,29). By so doing we best avoid hemorrhage into the anterior chamber, and prolapse of the vitreous, two accidents which may be due respectively to a conjunctival flap and to a section made too much in the periphery.

Ad. Weber has constructed a special form of triangular knife (Fig. 130) with which we obtain a linear incision similar to that which we have just described. It is introduced at the base of the cornea, in a plane parallel with the base, and is advanced in the anterior chamber till it reaches the point opposite to the point of puncture (Fig. 131).

Weber recommends the knife in two sizes according to the dimensions of the cataract.

Second Step: Iridectomy. Having intrusted the fixation forceps to an assistant, the conjunctival flap, if present, is everted on the cornea by means of the straight iris forceps ; the prolapsed iris is thus left completely bare. With the same forceps the iris is taken hold of towards the external part of the wound and gently drawn out ; it generally shows itself in the form of a triangle, which is incised at the very angle of the wound itself (Fig. 132). Then by a second snip of the scissors the iris is cut at the centre, and by a third at the internal angle of the wound. In doing this, care must be taken not to draw the iris into the angles of the wound, lest it should remain caught. To make the matter perfectly certain, we must watch, after the iridectomy, if the sphincter of the iris enters the anterior chamber, and promote its return by gentle pressure with tile spatula oil the angles of the wound. We have seen already that this result is most easily obtained when atropine has not been instilled into the eye before the operation.

If we wish to make a small iridectomy, or a simple incision of the sphincter, we return the iris to the anterior chamber ; because we can then seize as small a portion as we wish, and at the desired spot, which is impossible if the prolapse remains. Ad. Weber prefers to take hold of the iris with a blunt hook rather than with the ordinary forceps, and we are of the same opinion.

Third Step: Opening of the Capsule. After the iridectomy, and till the operation is finished, it is well to follow the advice of Horner, who causes the speculurn to be gently removed by an assistant thoroughly accustomed to do so, and thus all pressure which that instrument may exercise on the eyeball is avoided. W eprefer to have the lids separated by the fingers of an assistant, thus doing away with the speculum. The fixation forceps being taken from the hands of the assistant, the capsule is opened by two in cisions of the bent cystitome, both of which start from the inferior margin of the pupil, and go, the one towards the nasal side, the other towards the temporal, till they reach the superior margin of the lens. Generally the superior extremities of these incisions are united by a third made parallel to the superior border of the cornea. It is important to introduce the cystitome into the anterior chamber with great care, guiding it flatly along the posterior surface of the cornea. When the point of the instrument has entered the capsule, it is well to hold it almost parallel to the surface of the capsule, so that it does not penetrate the cataract too deeply ; ty neglecting this precaution we may easily dislocate the lens.

Arlt prefers to the cystitome a sharp hook, with which he opens the capsule in a triangular flap, and Becker uses a cystitome curved back so as to form a sharp hook, which we believe is much superior to the ordinary cystitome.

To obtain a still more complete opening in the capsule, Ad. Weber uses a double hook, the fine teeth of which are placed one beneath the other (Fig. 133). He moves it in the capsule from one side of the pupil to the other, and from the two angles of the capsular wound towards the incision in the cornea. He then cuts off a capsular flap which may remain attached to the hook. We have constructed a cystitome ( Fig. 13.0 which is introduced in the ordinary way into the anterior chamber; on arriving at the inferior margin of the pupil, by our pressing on a button the cystitome becomes double, and, on drawing it back towards the corneal margin, a large central opening is made in the capsule. Before withdrawing it from the wound we close it, and thus drag out the capsular flap. This flap is absent only when, from fear of penetrating the cataract, the instrument has been inclined too much. In this case it often happens that only one point enters the capsule, which is then opened as if by an ordinary cystitome. De Wecker has constructed a similar cystitome in the form of forceps.

Gayet has proposed to open the capsule of the lens near its superior border. For this purpose he makes slight pressure on the eyeball, so as to bring the margin of the lens into the corneal wound, and opens the equator of the cataract with the linear knife. Knapp also adopts the same method.

Fourth Step: Extraction of the Cataract. The removal of 'the lens is effected in the following manner :

A large curette is taken, and the back of the instrument is lightly laid against the sclerotic, close to the centre of the wound, so as to make it. gape. At the same time, with the fixation forceps, the ball is gently drawn downwards (Fig. 135). During this movement, the cortical masses come forward, and the superior margin of the nucleus begins to present itself. To hasten its expulsion, the back of the curette is gently slid along the sclerotic from one angle of the wound to the other, and vice versa (gliding movement). The pressure should be gradually and carefully increased till the greatest diameter of the nucleus crosses the wound. The pressure is then diminished, and simultaneously the curette is slid along the sclerotic to a greater distance from the wound ; it is moved from below upwards, in a line corresponding to the middle of the incision. just as the inferior margin of the nucleus leaves the wound, it is well, in order to prevent a needless separation of the lips, to direct the eyeball slightly upwards, and when it is in this position the fixation forceps should be removed.

Another means, proposed by von Graefe, of bringing about the expulsion of the cataract is the following : The back of the curette is applied to the sclerotic near the inferior margin of the cornea (Fig. 136). Slight pressure on this region, made towards the centre of the eye, causes the superior border of' the lens to appear in the wound.

The curette, slightly inclined forwards, is then guided on to the corneal surface, from below upwards, so as, as it were, to push the cataract out of the wound. If this second method be adopted, the fixation forceps must, at the beginning of the operation, be placed a little more towards the nasal side of the corneal periphery, otherwise there will not be space for the proper application of the coterie. In a few cases where the expulsion of the cataract is difficult, it is advisable to intrust the fixation forceps to an assistant, and to facilitate the removal of the lens by applying a second curette to the sclerotic border of the incision, which is thus opened more easily.

After the expulsion of the cataract, the surgeon takes the speculum from the hand of his assistant, who has held it till now, and carefully removes it.

Fifth Step. It very frequently happens that the whole of the cortical substance does not come out with the nucleus. For reasons already explained, it is important to remove it as thoroughly as possible. With this end in view, the lids are allowed to close till the aqueous is at least partially reproduced, and the upper eyelid is gently rubbed, as has been previously explained, in order to collect the cortical fragments as much as possible into the pupillary field; then the patient is directed to look downwards. By pressing lightly with the elevated superior lid the wound is made to gape, and the inferior eyelid is used to push the lens substance towards the wound. To clear the capsule of d9bris we may make use of injections of warm water (M'Keown), or solution of sublimate (Panas), or boracic acid (Wicherkiewitz). When the pupil appears quite black, we must cleanse the wound and the eye, carefully removing with small forceps the blood clots that are generally formed. Lastly, the aqueous humor, often mixed with a little blood, is evacuated. The normal condition of the pupil should be noted. If there be a conjunctival flap, it is replaced, either by sliding the convex surface of the small curved forceps over the cornea on to the sclerotic, or with the back of the caoutchouc curette. The manipulation, at the same time, removes from between the lips of the wound the cortical substance and iris pigment which are Hidden in that situation. In order to insure the thorough cleaning of the pupil, we may avail ourselves of focal illumination by a lamp or electric light if the daylight be insufficient.

Dressing and after Treatment. The dressing is the same as that used after flap extraction.

Little need be said as to treatment after the operation. The pressure bandage, renewed for the first time forty eight hours after the operation, should then be changed daily. As regards light, we must observe, for the first few days, those precautions which art usual after every cataract operation. We should keep the patient at rest, but in all respects less rigorously so than after flap extraction. As to diet, we may give anything which does not heat or require to be chewed. If a portion of the cortical substance remain in the eye, we early instill a few drops of atropine, and keep the pupil dilated if the conjunctiva can bear the use of atropine. As a rule, when the course of the recovery is normal, we abstain altogether from using atropine or eserine. After the first three or four days, the pressure bandage may be replaced by a small loose bandage, and at the end of the second week the patient may be allowed to go out if his eyes are protected by dark spectacles. When the operation has been perfectly normal, we rarely find any interruption in the natural progress of the recovery.

Of course, the same precautions as regards cleanliness and antiseptics are to be observed here as in the flap operation. Accidents which may happen during and after the Operation. If, notwithstanding the use of cocaine, the patient struggle considerably during the application of the speculum, or fixation forceps, it is better to administer chloroform till complete anesthesia is obtained; the inconveniences of so doing are, by reason of the form of the wound, much less to be feared than in flap extraction. It is then preferable to make the operation in the lower border of the cornea. We also use chloroform when palpation shows a marked increase of the internal tension of the eye, which is not diminished after the use of cocaine.

When the point of puncture has been badly chosen in relation to the margin of the cornea, if the knife has already entered the anterior chamber, it should be withdrawn, and the operation should be postponed. The extremely insignificant wound soon heals, and in a few days we may proceed with the operation. If the point of puncture is at the corneal margin, but too low or too high, this difference may be compensated by our choice of the point of counter puncture without changing the size of the incision. The only inconvenience which then arises is a slight deviation of the coloboma, which, according to rule, should be placed directly upwards.

When the point of the knife has been carried towards a point of counter puncture other than the one prescribed, and this is discovered before the sclerotic margin has been pierced, we may without fear draw the point of the instrument back into the anterior chamber and then direct it to the proper point ; the form of the knife prevents the escape of aqueous humor. It, however, escapes as soon as the point, in making the counter puncture, pierces the sclerotic, and sometimes raises up a large extent of the conjunctiva. This, when seen for the first time, is apt to cause alarm, but need not in the least alter our mode of action : it generally disappears with the cutting. of the conjunctival flap, during which we must be careful to turn the blade of the knife directly forwards.

The escape of blood into the anterior chamber, which often follows the excision of the iris, may hinder the precision of the movements of the cystitome ; we may, in such cases, make an attempt to remove the blood by causing the wound to gape, but in the majority of cases we are forced to allow it to remain, and with a little practice the capsule can be opened notwithstanding the blood.

Prolapse of the vitreous occurs when the wound is made too much in the periphery, or it may be occasioned by the contractions of the voluntary muscles, or, again, when the pressure of the instruments on the eye is too great ; in other cases, it is due to some diseased condition of the eye (partial atrophy of the zonule of Zinn). It naturally presents the greatest inconvenience when it takes place before the expulsion of the cataract. If by chance this accident takes place at the end of the, first step, the fixation forceps and stop speculurn should be removed at once, and the patient put fully under the influence of chloroform. A trustworthy assistant may then gently separate the lids with his fingers, whilst the surgeon very carefully accomplishes the various steps in the operation. It then becomes almost always necessary to use the curette or Weber's loop in extracting the lens, for any other manipulations may increase the prolapse of the vitreous, without insuring the expulsion of the cataract.

Where, on the other hand, the prolapse of the vitreous has taken place after the excision of the iris or after the rupture of the capsule, we advise the immediate extraction of the cataract by the curette or Weber's loop. It need not be said that, in all these cases, there is nothing more to be done than to close the lids, omitting the fifth step altogether, so that the bandage may be applied at once. Collapse of the cornea after the operation, even although considerable, does not prevent a normal recovery when the bandage is carefully applied.

Anomalies in the course of recovery require the same treatment as after flap extraction (see P 358).

It is rare that the ordinary progress of the recovery is interrupted by any serious accident after the third or fourth day. An effusion of blood into the anterior chamber has been observed at different times during the first day or two days after the operation, or even at a later period. It sometimes persists for a few days, and may recur even after complete absorption. This hemorrhage is never considerable, and disappears on the prolonged application of the bandage.

On the second, third, or even fourth (lay after the operation, we not unfrequently find a slight scrolls chemosis, Without tumefaction of' the lids, increase of the secretion, or infiltration of the wound in a word, without any other sign of irritation or infiltration This chemosis is probably due to the conjunctival flap. The patient complains of a slight feeling of pressure in the eye, which disappears when the chemosis is incised with curved scissors.

When the iris has not been carefully replaced, there may be, especially in eyes which are relatively hard, an imprisonment of that membrane in the cicatrix, and thus we may have the period of cicatrization prolonged, as well as a persistent susceptibility of the eye. Besides, in these circumstances, the pupil dilates very imperfectly under atropine, small staphylornata are found at the angles of the wound, and, in consequence of the cicatricial contraction, which also affects the sphincter of the iris caught in the wound, the free margin of the pupil is drawn more and more upwards. In this way the pupil assumes a form very unfavorable for vision. It is very difficult to improve this state of matters at a later stage without surgical interference, and this inconvenience prompts us once more to insist on the necessity of carefully excising the prolapse of the iris, and of watching closely the position of the sphincter during and after the operation. When necessary, we never hesitate to complete the iridectomy by again excising the iris at the points indicated, and we never rest satisfied with the operation till the sphincter has completely entered the anterior chamber, and is situated at some distance front the corneal incision as indicated in Fig. 137.

In cataract extraction, Kuchler makes a linear incision in the transverse diameter of the cornea (Fig. 138) ; the puncture and counterpuncture are made in the corneo sclerotic ring.

Liebreich extracts through a very small curved section, occupying the inferior portion of the cornea. The puncture and counterpuncture are made in the Sclerotic (Fig. 139) Lebrun extracts through a small medium flap. The puncture and counter puncture are made at i or 2 millimetres below the extremities of the transverse diameter of the cornea. The flap formed in the superior half of the cornea is about 3 or 4 millimeters high (Fig. 140).

In none of these three methods is iridectomy performed.

Edward Jaeger uses a special knife for cataract extraction (Hohl messer), and makes the puncture and counter puncture in the sclerotic at 2 millimetres from the margin of the cornea, and 3 below the tangent to its summit. This incision, placed at the superior margin of the cornea, should measure 12 millimetres.. The iridectomy, cystotomy, and expulsion of the cataract are the same as in von Graefe's method.

4. Extraction of the Cataract in its Capsule.

Since extraction has been adopted as the general method of operating in cataract, various attempts have been made to remove the entire crystalline system i. e., to extract the cataractous lens in its capsule. Such attempts, based on the fact that the capsule, if allowed to remain in the eye, often becomes a source of imperfect vision, have nevertheless been abandoned on account of the dangers to the eye which they involve. Indeed, this operation, in the majority of cases, gives rise to a more or less considerable loss of vitreous humor, which exposes the organ to serious dangers, and often causes the loss of the eye. It is, however, right to add that, when the operation succeeds, it gives the best results as to visual acuteness. This circumstance explains why certain of our Italian and Spanish confreres exclusively use the method of extraction in the capsule in their cataract operations.

The majority of surgeons who have adopted this method insist on the necessity of complete anesthesia in extracting with the capsule, evidently with the view of diminishing the muscular contractions of the patient, which increase the danger of prolapse of the vitreous body.

In performing extraction of the lens in its capsule, a large incision is generally made at the inferior half f of the cornea. Pagenstecher makes his incision in the sclerotic at a millimetre from the corneal margin, and leaves his flap attached by a small conjunctival bridge. He then performs ieidectomy, complete his section, and removes the entire lens by introducing a large curette behind it. Other operators complete their flap at once.

Delgado, of Madrid, has attempted to extract the cataract in its capsule as follows: He begins by introducing into the anterior chamber, as in discission per corneam, an instrument which combines the needle with a spatula; with this he detaches the lens, and makes it mobile by gentle pressure on the periphery of the cataract. Having done so, he withdraws the instrument, waits till the aqueous has again filled the anterior chamber, and then extracts the lens in its capsule, using von Graefe's peripheral incision and the superior iridectomy. Several operations performed in this way have given him very satisfactory results.

Extraction of the lens in its capsule does not appear to be admissible as a general method applicable to all cases, but should be restricted to those in which it seems probable that the strength of the suspensory ligament is defective for example, when the cataract is over ripe, when the iris is tremulous, and in strongly myopic eyes where a general distention of the globe exists.

WHAT METHOD OF CATARACT OPERATION SHOULD WE ADOPT?

It is evident that of all the various operations employed in senile cataract, flap extraction is the most perfect when it succeeds. It preserves a round, mobile pupil, which is a great advantage both as regards appearance and the function of the iris; but the writings of the ablest and most conscientious surgeons, able to testify concerning a sufficiently large number of extractions without iridectomy, leave no doubt as to the relatively large number of unsuccessful cases which followed the classical operation, as also the dangers which may arise even after a perfectly normal operation.

At present it is found by all surgeons who use von Graefe's method on a large scale that it gives a larger. number of perfectly successful cases; that cases of complete failure are much less frequent; that, in a word, the result of an operation is more in proportion to the way in which it has been performed. The dangers which, for the first fifteen days or even for a longer period, attended the recovery of an eye which had undergone flap extraction, are not present for more than two or three days in linear extraction, and the progress, as well as the duration, of the convalescence does not try in the same degree the patie nce of the surgeon or of the patient.

Since the advantages of von Graefe's method regarded as to the rarity of unsuccessful cases and the rapidity of the recovery have been generally recognized, flap extraction has been almost entirely abandoned. De Wecker, who, in 1875, attempted its revival with certain modifications (small peripheral flap and frequent instillation of eserine), returned, after a year or two, to the process with iridectomy, as being the method generally suited to cataract extraction.

Those who object to this method because it is combined with iridectomy, on the one hand lay stress on the extent of the lesion, and on the other on the necessary deformity of the pupil.

Whatever theoretical considerations may be raised in support of this objection, daily experience shows that the combination of extraction with iridectomy, far from increasing the dangers or retarding the recovery, seems rather to be beneficial, either by facilitating the complete expulsion of the cataract, or by modifying the conditions of the circulation and intraocular tension in some advantageous way.

As regards the deformity of the pupil which results from iridectomy, we cannot deny its optical inconveniences. These are a slight dazzling, and a more pronounced radiation than in eyes operated on without iridectomy. Yet even with an iridectomy, the visual acuteness may be sufficiently good.

Moreover, when we operate according to the directions laid down by the author of the method, performing the operation at the superior margin of the cornea, and taking care to avoid the enclosure of the iris in the wound, the artificial pupil is hidden by the superior lid, and the inconveniences which have just been cited no longer exist.

Again, what conscientious surgeon, or what intelligent patient, would hesitate to choose an operation shown to be superior by the number of satisfactory results, even at the price of some slight optical inconvenience or trifling defect ?

When possible, it is of great advantage to perform the iridectomy some weeks before the extraction of the cataract, and this rule should always be followed when the eye to be subjected to the operation is the last hope of the patient, or when the special circumstances of the case demand great care. If this method could be adopted in all cases, the number of successes would perhaps attain a maximum, but, for many reasons, the idea of two separate operations at a few weeks' interval is not often entertained by the patient.

Some oculists, especially in France, show a tendency to return to the principle of extraction without iridectomy, detaching the corneal border in about one third of its circumference. Graefe's knife is used in cutting this small flap. In order to avoid the use of more instrunients than are absolutely required, the capsule is opened with the point of the knife, either in its passage across the anterior chamber or after the section is completed. I)oubtless our progress in the knowledge of antiseptics, local it nest lies is and myotics warrants and explains these attempts; and their general adoption will depend upon the benefits arising from them, rather than upon the attacks now directed against extraction with iridectomy, which has been advocated for the past twenty years, and supported by numerous favorable statistics.

CATARACT DISCISSION.

Indications. This method may be used for all cortical cataracts of children* and young adults up to the age of twenty or twenty five. It is also used for zonular cataracts, when the extent of the opacity does not allow us to hope for a sufficient amount of vision from the formation of an artificial pupil. It is also employed to divide very thin secondary cataracts.

After the age of thirty or thirty five, the consistence of the cataract is usually such that absorption can only be effected very slowly and after repeated discission. Besides, the iris neither tolerates so well the contact of the lens fragments which escape through the capsular opening, nor the pressure of a cataract which has become soft and swollen from the penetration of the aqueous humor; so that discission of cataract at an advanced period of life exposes the eye to the serious risks of an iritic inflammation and its consequences.

By the method in question, we propose to incise the anterior capsule, and thus place the cataract in contact with the aqueous humor, which, entering into the lens substance, softens it and prepares it for absorption. The time necessary for absorption varies from a few weeks to several months, according to the age of the patient and the degree of consistency of the cataract. It takes place more quickly when a considerable quantity of the aqueous enters the lens substance, which happens when the capsule has been torn to a great extent. The free access of the aqueous humor to the cataract causes it to increase in volume proportionately to its consistence, and to the extent of the capsular opening.

The dangers from the sudden pressure of a bulky cataract on the iris require that we should previously study the nature of the cataract and the irritability of the iris. The special signs by which we estimate the consistence of a cataract have already been given in detail. The irritability of the iris may be to a certain extent determined by the effect of atropine on the pupil. If the pupil dilates rapidly, and if the dilatation is maintained, we may conclude that the iris will the more easily bear the consequences of the operation.

From what has been said, it may be gathered that the capsule maybe widely opened when the cataract is very soft and the iris not very irritable, a combination of circumstances most frequently met with in very young children. In cases of the contrary kind, the extent of the incision must be adapted to the special circumstances, and, as a general rule, it is better to make the capsular opening too small than too large. In the least favorable conditions the capsule should be simply punctured, and the operation repeated if the process of absorption is arrested.

In zonular cataracts it is always prudent to begin with a small incision of the capsule, on account of the presence of transparent cortical masses, which by their rapid imbibition considerably increase the size of the lens.

Preparation for the Operation. Cataract discission requires complete dilatation of the pupil ; consequently, it is necessary to instill previously a sufficient quantity of a strong solution of atropine. The patient, if a child, must be wrapped up in some covering, so as to keep the limbs still.

The instruments necessary for the operation are : Fixation forceps (Fig. 6o), and a discission needle. The latter should be so constructed that its neck completely closes the small opening made by the point, for then no premature escape of aqueous can take place. We generally use Bowman's stop needle (Fig. 141), which cannot be introduced further than its stopping point. The head of the patient, who as usual is in the recumbent position, is held steady, in the way that has already been described, and an experienced assistant separates the lids. In the absence of an assistant, the lid speculum may be used. The sur. geon stands before the patient when operating on the left eye, but behind his head when he wishes to operate on the right eye and prefers to use his right hand.

(a) Description of the Discission operation for Cataract.

The surgeon, taking the fixation forceps in his left hand, and the needle in his right, with the first takes hold of the conjunctiva near the internal and superior margin of the cornea The needle is held with its edge towards the surface of the cornea, which it pierces perpendicularly at a point opposite the margin of the dilated pupil, The puncture should be made downwards and outwards, and the iris must not be wounded. When the needle has passed into the anterior chamber, the surgeon lowers the handle of the instrument, and pushes the needle towards the superior aspect of the lens to within a millimetre of the pupillary margin (Fig. 1142). He then turns the edge of the needle down on the capsule and makes a longitudinal incision in it, at the same time withdrawing the instrument slightly so that it does not penetrate the lens substance too deeply. In cases where, according to the rules already laid down, the operation should end with a simple incision, there is nothing more to be done than to withdraw the needle, and take off the fixation forceps. The assistant allows the lids to close, and all is finished. When, on the other hand, circumstances allow a more extensive incision, the needle is semirotated so that the two blades face the angles of the eye. The point is then directed towards the internal margin of the pupil (Fig. 143), to within a millimetre from the margin of the iris, and a transverse incision is made, which should also terminate at a millimetre from the external margin of the pupil. Whilst making this second incision, we must also, for the reason already stated, withdraw the instrument slightly from the wound. The surgeon should carefully avoid making any great pressure with the collar of" the needle oil the conical wound, and should hold his fingers, during the various steps of the operation, so that the corneal opening may be the centre of rotation of all movements of the needle.

On finishing the operation, a compressive bandage is applied. It is better to keep the patient in the recumbent position for the first twenty four hours in a dark room. The bandage is changed as usual, a few drops of atropine being instilled each time. The use of atropine must be continued during the entire time taken by the absorption that is to say, till all lenticular opacities have completely disappeared, If the progress of the recovery be not interrupted, the compressive bandage is replaced after a few days by a small loose bandage, and at a later period by dark glasses.

If we find, some time after the operation, that the process of absorption has been arrested, the opening in the capsule having become closed (usually by the formation of a hyaline substance which unites the edges of the wound), the operation must be repeated and a fresh discission made, all the more courageously if the size of the cataract has been diminished by partial absorption. To ascertain that the absorption has been arrested, and that there are no longer portions of the lens substance swollen with the aqueous humor, it is almost indispensable to examine with focal illumination. Before deciding to repeat the application of the needle, it is well to wait till all irritation or redness of the eye (pericorneal injection) has passed away. The time required for complete absorption of the cataract after discission varies with the age of the patient and the consistence of the cataract. In young children absorption often takes place in from six to ten weeks, and one discission only is sufficient. We know that at this age the iris is not very irritable, and we may, therefore, make a larger opening in the capsule. With older patients, the discission has to be performed with more caution and the operation must be repeated several times, so that the complete absorption of the cataract may require several months, and even more than a year.

Accidents which may Supervene after the Operation.The most frequent accident which may occur after discission of a cataract is inflammation of the iris. The patient then complains of pain in the eye, as also in the surrounding structures, and in the entire inferior half of the head on the side of the operated eye. Along with these symptoms there is pericorneal injection, and the aqueous humor becomes muddy, the iris changes in color, and the pupil contracts. If the iritis is a consequence of the increased pressure of tile swollen cataract, and if it does not readily yield to the continued application of ice (Arit) and instillation of atropine, which by dilating the pupil, withdraws file iris from gill dangerous pressure, it is in vain to strive to subdue the Inflammation by the ordinary remedies. that is to say, by blood letting at the temple, instillation of atropine, and administration of mercurials. We should rather hasten to free the iris from the unwonted pressure which has given rise to, and which keeps up, the inflammation.

The only efficacious remedy in such circumstances is to extract the cataract by a linear incision combined with iridectomy ; and we cannot put off doing so without exposing the eye to the most serious risks, and the patient to the severest pain.

The necessity of freeing the inflamed eye as quickly as possible of the cataract, which is the direct cause of the inflammation, is too evident to require to be enforced. It might seem, a priori, a dangerous proceeding to combine extraction with iridectomy, when the iris is the seat of an inflammation. Yet the iridectomy is necessary to facilitate the expulsion of the cataract, for the pupil is generally firmly contracted and often cannot dilate because of the presence of posterior synechie. It has also been shown, as we have already said in speaking of iridectomy, that this operation, far from increasing the iritic inflammation, may be the most powerful means of checking it.

A slighter form of iritis has also been observed when, in consequence of a very large incision in the capsule, a considerable quantity of the lens substance or the nucleus falls into the anterior chamber. To check this inflammation, we may try the effect of atropine by itself; but if the symptoms of iritis persist or increase, it becomes urgent to evacuate the masses contained in the anterior chamber by a paracentesis performed at the inferior periphery of the cornea. After this has been done, the iritis generally disappears, or, at least, rapidly yields to the usual applications.

In cases where the soft and liquid consistence of the cataract enables us to foresee that a great quantity of the lens substance will fall at once into the anterior chamber, and when the youth of the patient forbids linear extraction, von Graefe has proposed to perform discission through the cornea with a larger needle than is generally used.

Holding this instrument on the cornea in such a manner that the edges are directed towards the angles of the eye, the surgeon transfixes the membrane so as to enter the anterior chamber, and the discission is finished before the aqueous humor can escape. Whilst the needle is being withdrawn, slight pressure should be made on the inferior lip of the corneal wound, thus permitting the escape of the aqueous humor, and a certain portion of the soft cataract.

If, after this, the portion of the lens remaining in the eye is too great, we wait till the aqueous humor has been re accumulated, at least in part ; then we again gently open tile wound with an Anel's stylet, curved oil its external lip.

For the rest, it suffices to have removed the more fluid portions of the cataract, and we may leave the few remaining gelatinous flakes to be absorbed, as they do not cause any considerable irritation. These cases could also be operated by suction. Another mishap, which has been sometimes noticed, consists in an irritation, or even infiltration of the cornea at the point of puncture.

This complication, although very unfrequent, may arise from infection, or from the cornea having been injudiciously dragged on by the needle. It generally yields to antiseptics (iodoform, sublimate, galvano cautery), and the prolonged use of the tight bandage, together with tile occasional application of hot fomentations.

(b) Discission Combined with Iridectomy.

The ease with which cataract discission is performed, and the relatively slight danger to which it exposes the eye, have naturally raised a desire to extend the indications of the operation as widely as possible. Unfortunately, it cannot be applied to the ordinary cataract of mature life, for this does not readily undergo absorption, requiring a considerable length of time (from eighteen months to two years), during which the eye is exposed to serious complications iritis, glaucoma. Such dangers are all the more to be feared, as the structures involved are more apt in advanced life to take on an inflammatory process than in youth. Sometimes, even after the age which is fixed as the limit for discission (twenty to twenty five), we find varieties of cataract, which, from their consistency, might admit of this method of operation, were we not afraid of exposing the entire organ, especially the iris, to the risk of the prolonged process of absorption. On the other hand, there are, even in youth, at which period the eye more easily bears the consequences of a discission, varieties of cataract, which, after discission, undergo an excessive and dangerous amount of swelling. In both cases, prudence obliges us to forego discission, notwithstanding the desire to use a method which, if properly followed, may certainly be considered as giving the best results. Von Graefe has devised a plan, by which, even in such cases, we may use discission if it is combined with iridectomy.

The results of this combination are so satisfactory, that it seems to its of special importance to indicate very carefully the cases in which it deserves a trial.

Firstly, in cases of cataract in voting persons, where atropine does not sufficiently dilate tile pupil. The inefficiently of the atropine instillations sometimes arises from tile presence of synechie, which have been formed by a previous iritis ; in other cases it depends on some special condition of the iris tissue. We are also obliged to have recourse to preliminary iridectomy when we wish to perform discission in the case of a person who is more than fifteen years of age, especially in those forms of cataract whose very slow absorption is not without danger to the eye, as, for example, in zonular cataract. We do not, however, say that fifteen is the extreme limit between simple discission and discission combined with iridectomy; but, given this form of cataract in persons of different ages, we must judge as to the necessity of preliminary iridectomy chiefly by the greater or less irritability of the iris.

We know, for example, that zonular cataract, after discission, usually becomes greatly increased in volume, and if the circumstances of the case cause us to perform discission at a relatively advanced period of life, we should take the double precaution of performing a preliminary iridectomy, and of making our first discission very small, leaving ourselves free to repeat it when necessary. Yet, after an iridectomy we can rupture the capsule more extensively, and thus shorten the period of absorption ; for the swollen cataract, and the lenticular flakes which are detached, are brought less in contact with the iris, because that membrane can yield more freely to the pressure, and, the sphincter being cut, offers less resistance. Again, if there should be inflammation, the iridectomy renders it less dangerous. It should also be added that, in recent times, for this class of cataracts, the method in question has often been replaced by von Graefe's linear extraction, which, in special cases, has this advantage, that the patient is freed from the cataract at a single sitting; whilst discission with iridectomy requires at least two operations, if not three or four, and a considerable time must elapse before the cataract is completely absorbed. Von Graefe's extraction should therefore be preferred, when the cataract has a certain consistence, as is occasionally found in young persons, when the patient cannot remain so long under the observation of the surgeon as may be necessary for discission ; or when his eye presents symptoms of great irritability.

As to the way of performing discission. with iridectomy, little remains to be said.

The iridectomy is best made at the superior aspect of the eye, so that the artificial coloboma of the iris may be as far as possible concealed by the superior lid. As to the details of this operation we refer the reader to the description which we have given under the heading of Iridectoiny.

It is necessary to allow a sufficient time to elapse between the iridectomy and the discission ; sometimes twelve or fifteen days may suffice ; in other cases we must wait several weeks, till all trace of irritation has disappeared.

The after treatment, and the remedies to be employed in case of accident, are the same as after simple discission.

(c) Discission for Artificial Ripening and Forster's Method.

Not unfrequently do we see cases of cataract, where the slowness with which the disease matures severely tries the patience of the sufferer who desires to have his vision restored. A time then comes when the patient can no longer use his eyes, whilst the surgeon, from the special appearance of the cataract, and from his observation of the previous course of the disease, is in a position to conclude that complete maturity cannot be attained for a long time. On the other hand, we always hesitate to extract a cataract which is not perfectly ripe, being deterred by the fear that a portion of the lens substance which is still transparent may be left in the eye, and that, by its secondary swelling, it may give rise to serious complications during the period of recovery.

As an escape from this disagreeable position, which gives us the alternative of either performing a dangerous operation, or allowing the patient to remain for a long time in such a condition that he cannot use his eyes, and that at a period towards the close of life, it has been proposed to hasten the formation of the opacity in those portions of the lens which remain transparent, by introducing a discission needle. This ingenious idea has, however, not met with general favor.

The process of Forster for artificially ripening the cataract consists in performing iridectomy, after which, the anterior chamber being drained of its contents, a sort of kneading of the lens is made, with the blunt end of a strabismus hook across the cornea and slight pressure applied upon the surface. The movements of the hook should be made from the centre towards the periphery, and also in a concentric manner. After one or two days, as a result of this manipulation, opacification of the previously transparent parts of the lens takes place, and its extraction may be made some weeks later.

When the lens is removed before its maturity, portions of its cortical substance are likely to remain adherent to the capsule, the result of which may be an imperfect cure, inflammation, or secondary cataract. To combat this tendency, Wicherkiewitz advocates washing the capsular sac by means of injections, of solution of boracic acid thrown directly into it, a method from which he has derived excellent results. M'Keown advocates the same procedure, using warm water and a Special syringe (scoop syringe).

Preliminary discission has also been employed, chiefly by English oculists, as a preparatory step to suction, in those cases where the cataract is not completely soft or liquid: on this subject we have already expressed our opinion.

(d) Couching of the Cataract.

Couching the earliest o eration for the relief of cataract possesses for us only a historical interest. It will be well, however, to give a brief description of it, and to note the reasons which led to its abandonment. Examination of the statistics of couching operations show that, after a lapse of one or two years, little more than half the operated eyes permanently regained their vision. These, moreover, were constantly menaced with the serious complications liable to result from the presence of the lens in the vitreous, for it was only in a very small number of cases that the reabsorption of the lens was complete. Although these facts were perfectly well known for a long time, even the opponents of the operation were obliged to resort to it in exceptional cases, where flap extraction was impracticable. Thus it occupied a place in ocular surgery up to the time when von Graefe's operation became universal.

There were different methods of displacing the cataract, the most important of which was to reverse the lens (Fig. 144) as it was being pressed downwards, in such it manner that the anterior surface was directed upwards, the instrument used being a slightly curved cataract needle, with a lance shaped head (Fig. 145). The pupil was dilated with atropine, and the puncture made in the sclerotic about 3 millimetres from the temporal border of the cornea (Fig. 146). By an upward and outward movement of the handle of the needle the lens was displaced downwards and backwards into the vitreous. Then, after pausing a moment to assure himself that the lens remained depressed, the operator withdrew the needle, taking care that its surfaces were in the same position as upon entering. This operation merits no place in surgery now, having been entirely superseded by the extractive methods.

OPERATION FOR SECONDARY CATARACT.

Under the name of secondary cataract are included opacities of various kinds, which are formed in the pupillary field after a cataract operation, and which prevent the complete re establishment of vision.

If we carefully examine with focal illumination eyes which have been operated on for cataract, and in which, after the anomaly of refraction has been corrected according to the ordinary rules, the visual acuteness is less than it should be, taking into account the patient's age, we often find that the deficiency in vision is caused by the presence of an exceedingly slight opacity, stretched like a cob web behind the pupil. This is then a first variety of secondary cataract, and it arises from the formation of a new tissue by the proliferation of the epithelial cells of the anterior capsule.

In other cases the capsule itself becomes thickened, so that a denser opacity is formed, which can be seen behind the pupil by simple inspection. Again, in a third series of cases, the iris takes a part in the inflammatory process, and an iritic exudation is then added to the capsular opacity. This deposit may vary from more or less numerous simple synechie to the formation of true plastic deposits.

The mode of operation must vary according to the nature of the secondary cataract.

As a general rule, we must take care not to perform any secondary operation shortly after the extraction of the cataract. The time which we must wait varies with the duration and severity of the inflammatory process which the eye has undergone. We should decide to perform a secondary operation only when all traces of irritation, such as swelling of the lids, photophobia, pericorneal injection, have disappeared. If we do otherwise, we are apt to revive the inflammation, and not only lose the benefit which may be derived from our operation, Nit also find that other opacities art added to those which already exist. It then becomes necessary to subject the patient to another long period of waiting before we can attempt another operation on that eye. We must be very specially careful when we have to deal with the plastic membranes which are formed in iritis. These membranes, always highly vascular, readily become the starting point of fresh inflammation when they are irritated by contact with instruments. In such cases, we must delay the operation for the secondary cataract for a year or more, till all irritation has passed away from the eye, the vascularity of the membranes has disappeared, and the eye is in a state of perfect rest. Still, this period of waiting is not always thus prolonged, and when the opacity is inconsiderable we are sometimes at liberty to perform the operation for secondary cataract a few months after the extraction of the lens.

In the first variety of secondary cataract which we have mentioned, simple discission always suffices to effect a central opening in the slight ways mes more easily opacity found in the pupillary field. As theseisopsoamcietiteis are not al easily seen with ordinary light, the discissio performed in a dark room with the aid of focal illumination.

In attempting to operate by discission on cataracts of the second class, we often encounter an insurmountable difficulty, the opacity yielding before the edge of the knife, which cannot succeed in cutting it. The extraction of such opacities, for which numerous instruments have been invented (capsular forceps, Fig 78; Liebreich's forceps, modified by Mathieu, Fig. 147 ; Serretelles, Figs. 148 and 149), requires, as a first step, the formation of a corneal incision, and is often dangerous, or even impracticable; for, not unfrequently, there are more or less numerous adhesions between the secondary cataract and the iris, which is, therefore, inevitably exposed to considerable traction.

If, however, we attempt to extract these opacitie, we must previously divided the synechie, or perform an iridectomy where they are situated. When the adhesion is only partial, we can also make an incision in the cornea at the point of adhesion, take hold of the secondary cataract at the part where it is free, extract it, and cut it off near the corneal surface (Arlt).

The wisest operation for this variety of cataract is that indicated by Bowman, and known as discission by two needles (Fig. 15o). To perform this operation, the surgeon with his left band introduces a discisSion needle through the internal portion of the cornea into the opacity itself. The eye being thus fixed, he introduces a second needle with his right hand, through the external part of the cornea, directing it towards the point in the opacity where the first needle is situated. He then attemps to War the secondary cataract by separating the points of the needles. By this manipulation, which is somewhat diffi cult to perform, he succeeds in making an opening in the pupillary opacity sufficiently great to permit of vision.

Agnew, of New York, operates in these cases as follows: With a von Graefe's cataract knife he transfixes the cornea in its horizontal diameter so as to obtain a wound nearly two millimetres from the nasal and temporal margins of the cornea. While withdrawing the knife, he pierces the capsular opacity with its point. He then introduces two hooks, which are almost blunt at the points, the one by the opening on the nasal side, the other by that on the temporal, and inserts them into the opening made in the cataract by the point of the knife. By traction on the two hooks he dilates the opening as much as may be required, without dragging either on the iris or ciliary body.

In the other varieties of secondary cataract, it is almost always necessary to perform iridectomy or iridotomy, or perhaps a combination of these two operations. An iridectomy, sometimes very difficult to make in these cases, may be advantageously made with von Graefe's linear knife. When we have succeeded in establishing an opening in the iris, we try to form a slit in the plastic membranes with a strong hook. For this purpose we use a resistant and strongly curved hook, which is implanted in the membranes, so that, if possible, it may tear away portions of them. Often, in serious cases, the opening thus effected again becomes closed, and even after repeated operation we are not always successful in forming a small artificial pupil.

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 sequela of a destructive irido cyclitis, 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 triangular 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 tile 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 of 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 subcorneal 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 forwards."

De Wecker has invented scissors with which iridotomy may be very conveniently performed.

An incision 4 millimetres long is made in the cornea and iris with a triangular knife, in the corneal periphery where the radiating fibres of the iris converge at the superior margin. Through this opening, one branch of the scissors is introduced behind the iris and the other in front, and an incision, 5 or 6 millimetres in length, is made down¬wards and inwards. If the opening in the iris does not seem to be wide enough, a s econd incision is made downwards and outwards. In this way an iris flap is formed, which contracts.

To simplify the operation, as also to avoid the contusion inseparable from the introduction of the scissors and the escape of vitreous, Sichel follows von Graefe's original method, using a special instrument called an iridotome (Fig. 74), with which he penetrates the anterior chamber and makes one or two incisions in the pupillary membranes which converge towards the pupil. Galezowsky has also devised a small falciform knife for this operation. The double edged needle which von Graefe used in separation of the retina may also be very conveniently used.

In cases where the sphincter of the iris is caught in the cicatrix and sets up a prolonged irritation, Green has strongly recommended the following proceeding: The cornea is incised with a straight triangular knife at about 2 millimetres from its external margin, and at the same time tile iris is pierced ; then De Wecker's scissors are introduced by the opening one branch behind the iris, the other in the anterior chamber. The scissors are advanced to 3 millimetres beyond the opposite pupillary margin, and both margins, as well as the intervening membrane, are divided by it single snip.

When, from atrophy of its tissue, the iris has lost its power of retraction to such an extent that section of that membrane does not afford a sufficient pupillary opening, simple or double iridotomy does not suffice. Here we have to deal with considerable exudation behind the iris, with disorganization of its tissue and flattening of the anterior chamber.

In such serious cases Ad. Weber and von Graefe advised that a double edged, slightly curved, lance shaped knife should be used, which should be made to traverse the cornea near its external margin, and to pass behind the iris nearly to the opposite border of the cornea, at which point it should be brought out to its entire breadth from behind the iris. All the tissues should be cut at the angles of the wound with a pair of very fine scissors (see Fig. 79), one branch of which should be introduced behind the iris, while the other remains in the anterior chamber. The tissue thus circumscribed is removed with a strong pair of capsular forceps. Later, von Graefe made use of linear section for this kind of iridectomy (compare P¬396). Bow man also operates on thick secondary cataracts by two incisions made simultaneously with two triangular knives at the external and internal margins of the cornea, piercing the cornea, the iris and the cataract. The section of the tissues is finished with scissors, and the extraction is effected with a pair of forceps. De Wecker also uses a triangular knife, which he introduces in its entire breadth through the cornea at its superior border, at the same time incising the iris and secondary cataract; the knife should be directed as much as possible parallel to the iris. With two cuts of the scissors, which begin at the angles of the wound and converge towards the inferior margin of the cornea, he excises a triangular portion, which must be extracted with iris forceps. Another method, devised by Bowman, may be had recourse to in operating on adherent secondary cataracts. In consists in penetrating the anterior chamber with a large triangular knife at the superior margin of the cornea. When the point of the knife reaches the centre of the normal pupil, it should he pushed behind the iris and false membranes so as to make an incision 4 millimetres long in the iris and capsule (Fig. 151). The portion thus circumscribed is excised by means of small scissors. The vertical section, a, b, should only be made when we are unable to detach the iris from the opaque particles which obstruct the pupil.

KrUger has constructed an instrument in the form of a punch, with which he removes a morsel of the membranes which block up the pupil. The results obtained with this instrument in desperate cases of which we have seen two remarkable instances deserve the greatest attention.

ART. M Dislocation of the Lens.

The lens may be displaced in various ways. Sometimes it swings round its centre of rotation, which, however, maintains its normal situation (incomplete dislocation) ; sometimes the lens is altogether displaced (ectopia), either remaining between the iris and the vitreous body, being displaced upwards or downwards, to the nasal or to the temporal side, or being carried into the anterior chamber, or into the vitreous body. If there is rupture of the sclerotic, it may be found beneath the conjunctiva. It may even be completely expelled from the eye.

The symptoms of displacement of the lens are very characteristic.

1. Incomplete Dislocation. When the lens is removed from its normal position, the iris, which was in apposition to its entire anterior surface, loses its support. There is then an undulatory movement at the part where the lens is absent ; and at this point we can see a tremulous condition whenever the eye moves. The other parts of the iris are pushed forwards by the margin of the lens, which is nearer to the cornea. Consequently, on this side, the anterior chamber is perceptibly shallower, whilst it is deeper at that part where the iris has lost the support of the lens.

When the dislocation is well marked, it is not difficult to see, with an ophthalmoscopic mirror, the margin of the lens thrown backwards when the pupil is dilated. The margin appears as a black line on the red fundus of the eye. This line is, like the equator of the lens, convex, and divides the pupillary field into two parts. An experienced observer will at the same time notice that the ophthalmoscopic image of the fundus is formed at different distances, according as he observes it through one or other uf the two portions into which the pupillary field is divided.

The disturbance in vision varies with the degree of dislocation.

When the displacement is very slight, the normal visual acuity is scarcely interfered with, except in so far as there is a more or less complete absence of accommodation. If the movement of rotation has been sufficiently great to throw the margin of the lens into the pupillary field (the pupil being dilated), vision is very much disturbed, and the patient may suffer from monocular diplopia. If the luminous rays gain entrance by that part of the pupil in which the lens lies, we shall find a strong myopia with irregular astigmatism.

If the lens before displacement was affected with cataract, dislocation may restore vision to that eye, by removing from a portion of the pupil the obstacle which the cataract offered to the transmission of luminous rays.

Etiology. Any traumatic cause, such as a blow sustained on the eye, or on its surrounding parts, may determine incomplete dislocation of the lens. This is all the more easily produced if there already exist such predisposing causes as fluidity of the vitreous body, relaxation or rupture of the zonule of Zinn, as is found in cases where the anterior portion of the eyeball is dilated (sclerectasia anterior). In such cases the dislocation may occur spontaneously.

At other times, incomplete dislocation is caused indirectly by a portion of the iris being engaged in a peripheral staphyloma of the cornea; if this portion of the iris adheres to the capsule, the lens is also involved in the same process.

Again, congenital dislocation of the lens has been observed, sometimes even in both eyes, and in several members of the same family. It would, therefore, seem to be hereditary. As a rule, the displacement increases as age advances.

Treatment. When the displacement of the lens is so slight that the vision does not suffer, there is no call for interference. If necessary, we order glasses suited to the state of the refraction and accommodation. In cases where the movement of rotation has brought the margin of the lens into the field of the dilated pupil, and the lens has become opaque, vision may be re established by an artificial pupil similar to that made in zonular cataract. As this operation is always performed so that the artificial pupil is clear of the lens, whether opaque or not, the eye will then be, as far as vision is concerned, in the same condition as after cataract extraction (consult Article on Aphakia at the end of this chapter).

2. Complete Dislocation. The tremulous movement of the iris, and the changes in the depth of the anterior chamber, will be the more pronounced the greater the portion of iris deprived of its support by the dislocation of the lens. If the margin of the dislocated lens occupies the pupillary field, it forms a curved line, which is of a grayish color to focal illumination, but appears black to the ophthalmoscope.

We may ascertain the portion of the pupillary field in which the lens is absent by its deeper color, and by the absence of such reflections as come from the capsule ; which are, on the other hand, easily seen ith focal illumination in the portion of the pupillary field still occupied by the lens.

Again, ophthalmoscopic examination not only reveals the edge of the lens in the pupil, but also the difference of refraction in the two portions of the pupillary field, and sometimes, when the lens acts as a prism, we see simultaneously two ophthalmoscopic images.

On examining the functional condition of the eye, we at once detect the deficiency in the accommodation which is always present. The state of the vision, moreover, depends on the size of that portion of the pupillary field which is deprived of the lens. When the margin of the lens occupies the pupil, even when it is retracted, there is generally, on account of the irregular refraction of light (astigmatism), considerable disturbance of the vision. In such cases, also, patients complain of monocular diplopia. When the lens no longer occupies the pupil to any great extent, it is possible, either by a stenopaic slit, or by myotics, to make the light enter only by the portion of the pupil deprived of the lens ; and then vision may be considerably improved by very strong convex glasses.

If the lens is opaque, the diagnosis is much more easy; for we then see that a portion of the pupil has been rendered free of the preexisting opacity, and the eye suddenly recovers to a certain extent the vision which had been destroyed by the presence of the cataractous lens.

Etiology. Dislocation of the lens is sometimes congenital, and frequently occurs in several members of the same family. In such cases the lens is, as a rule, transparent, but smaller than in the normal part wanting (coloboma of the lens). Sometimes it is so small that it slips through the pupil into the anterior chamber whenever the patient bends his head forwards. We find coinciding with this condition a certain amount of amblyopia, and often some nystagmus.

When the displacement of a transparent lens takes place suddenly, it almost always is the result of an injury which has produced relaxation or rupture of the suspensory ligament. In every case the displacement may gradually increase.

The dislocated lens sometimes remains transparent for a length of time but more frequently it becomes opaque either immediately, or a few months after the accident.

(a) Dislocation of the lens into the anterior chamber is easily diagnosed whether the lens preserves its transparency or becomes cataractous ; in the latter case it is generally shrivelled. A transparent lens enclosed in its capsule appears in the anterior chamber as a very large pearl, and may remain transparent for a very long time. Rarely is its presence tolerated without producing symptoms of irritation, which are specially to be feared when the lens partially rests in the pupil. Sometimes the dislocated lens contracts adhesions with the cornea or iris, and becomes the starting point of some serious inflammation, which may threaten the existence of the eye (iritis, iridochoroiditis, glaucoma).

When there is, along with the dislocation, rupture of the capsule, the lens substance becomes swollen from the contact of the aqueous humor, and, by pressing on the iris, sets up an irritation, the intensity of which is in proportion to the rapidity with which the lens substance has become swollen.

As to vision, if the dislocated lens is transparent, the patient may still be able to see very near objects, the increased curvature of the lens, and its distance from the retina, making him very highly myopic.

Treatment. In dealing with a dislocation into the anterior chamber, we may, first of all, provided there are no inflammatory symptoms, attempt to reduce the lens in the following matter: Having widely dilated the pupil with atropine, the patient's head is laid backwards, and gently shaken from before backwards with the surgeon's two hands. If the lens return behind the iris, the patient must be kept on his back, and the pupil must be kept contracted for a considerable time with eserine.

If the lens has already set up an inflammation, or if there has been a rupture of the capsule, it would be imprudent to attempt its reduction. We may try to protect the iris from the mechanical action of the lens by keeping it dilated with atropine ; but, should the irritation persist, we must extract the lens through a linear incision in the cornea, or, better still, by a flap incision.

( b) Dislocation of the lens into the vitreous body produces a tremulous movement of the entire iris, and the absence of the capsular reflections. With focal illumination, and more clearly with the reflecting mirror of an ophthalmoscope, we can detect the lens in the vitreous body. It is recognized by its characteristic form, by the peculiar brightness of its margin, and by the movements which it executes round the portion of the suspensory ligament to which it is attached. These movements resemble those of a door on its hinges, and are easily seen when the eye is moved.

The vision of the eye, except when there is some other lesion accompanying the dislocation, is such as is found in an eye deprived of its lens (consult Article on Aphakia).

A lens thus displaced in its capsule may retain its transparency for a long time. Sometimes its presence in the vitreous body does not occasion any inflammatory symptom; sometimes it sets up serious inflammation, or a simple non inflammatory glaucoma. Our treatment must be regulated by the special circumstances of the case. If the lens does not cause any disturbance, it is needless to interfere ; if it becomes a source of irritation, we must attempt to remove it by means of a hook or curette, after having made an iridectomy.

(c) Dislocation of the lens beneath the conjunctiva, after rupture of the sclerotic, is always the result of violent injury. It is exclusively observed in persons whose age would indicate a diminution in the elasticity of the sclerotic. This rupture of the Sclerotic generally takes place in front of the insertion of the recti muscles, at the superior and internal margin of the cornea. Violent injury, which alone can produce dislocation of the lens, will also give rise to other inflammatory symptoms, such as swelling of the lids, subconjunctival and intraocular hemorrhage. When it is possible to examine the eye, we are sure to find some lesion of the iris, a portion of which is caught in the sclerotic wound; we shall find that the remainder of the membrane is tremulous, the pupil irregular and without capsular reflections, if the lens has been dislocated in its capsule. When, however, it has been ruptured, the debris will be found in the pupillary field. Again, at the point indicated, a small tumor, having the characteristic form of the lens, is observed.

We may remove the lens through a small incision made in the conjunctiva over the tumor. A compress must be kept on for several days.

(a) Complete expulsion of the lens from the eye has been observed after such severe contusion of the eyeball as has produced a large wound in the sclerotic and cornea e. g., after a blow from the horn of an ox. Strange to say, eyes damaged in this way have been known to recover, notwithstanding the serious nature of the injury. The absence of the lens is then easily detected by the symptoms already indicated viz., tremulous iris, absence of the capsular reflection, alteration in the refraction of the eye. At the time of the accident, it suffices to clear the wound, to excise the hernie of the iris, and to apply a compressive bandage.

In our prognosis, it is important to remember that, notwithstanding an apparent recovery, eyes which are so seriously injured often bccome atrophied. This is the result of chronic inflammation due to the enclosure of the iris or ciliary body in the wound, or may supervene after separation of the retina. We must also consider the risk of sympathetic ophthalmia.

ART. III. Aphakia, Absence of the Lens.

The term aphakia is applied to that condition of an eye in which luminous rays in their course from the cornea to the retina do not encounter the crystalline lens, which has either been removed by operation, or has been dislodged from the pupillary field by dislocation.

The symptoms of this condition are: Tremulous iris, its support being gone, absence of the capsular reflections, and, again, the peculiar state of the refraction of the eye.

The refractory power of the eye is considerably diminished by the absence of the lens, so that luminous rays are no longer brought to a point on the retina, but considerably behind that membrane. If the eyeball is of normal length we have thus a high degree of hypermetropia, sometimes complicated with astigmatism, which should be corrected by strong convex or cylindrical glasses, the choice of which will be explained in the next chapter.

The lens being also the organ of accommodation which allows the eye to see near at hand as well as at a distance, this power will be absent in aphakia. Eyes in which the lens is absent, when provided with glasses, can only see distinctly at one distance ; they require a different glass for each separate distance at which the patient wishes to work. The methods of choosing these glasses is explained in the following chapter.

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