Chapter XV: Part 15

_Abrasion_ of the conjunctival covering of the cornea is produced by accident, or follows incited action of the vessels. The abraded surface either ulcerates, or contracts and heals kindly, with or without opacity of the part. Breach of surface in the cornea,—whether an ulcer, an abrasion, or a raw surface, caused by the giving way of a pustule, or of a small abscess,—is constantly liable to irritation, on account of not being protected by mucous membrane and mucous discharge: even the contact of the tears irritates, and keeps up inflammatory action in the membranes. When the ulcerative process ceases, lymph is effused, and a grayish halo forms around the sore; the ash colour of the surface of the sore disappears, and is succeeded by florid granulations, extremely minute, which fill up the cavity; cicatrisation follows in due time, with subsidence of all the symptoms and appearances of inflammation. There remains, however, an opaque speck of a pearly hue corresponding to the sore, but occupying rather less space. When the cornea is perforated by ulceration, the sore sometimes shows no disposition to heal, becoming a fistulous aperture through which the aqueous humour is from time to time discharged. By this condition of parts vision is much impaired, the cornea being always more or less flaccid. Touching the fistulous opening with the nitrate of silver, reduced by scraping to a very fine point, will often promote a healthy action in the tissue, and effect adhesion of its sides.

The pearly speck which remains after cicatrisation of a corneal sore is termed _Leucoma_, and is permanent. It is generally of an uniform colour, but occasionally a black speck is perceptible in some part of it. For, when an ulcer lays open the anterior chamber, part or the whole of the aqueous humour is evacuated, and the iris falls forward; a portion of the iris falling into the opening, provided this is not in the centre of the cornea, closes it up, and becomes adherent to that part. If the opening is large, the prolapsus of the iris is considerable; and in some cases this membrane, being pressed on by the humours, is forced through the opening in the form of a small bag. This change of position is termed _Hernia of the Iris_; and the dark sacculated portion of the iris which projects from the surface of the cornea is called _Myocephalon_, from its resemblance to the head of a fly. The myocephalon may remain for a considerable time, or may sphacelate and drop away. The pupil is thus rendered irregular, is perhaps nearly obliterated, or is drawn down behind the opaque part, and thereby rendered totally useless to the patient. The impairment of vision caused by Leucoma depends on the size and situation of the speck. The disease is irremediable, though the thin cloudy opacity, which frequently surrounds the leucoma, may be dissipated. The operation of artificial pupil is sometimes required, in order to afford a degree of vision in this affection of the cornea,—as well as in the speck of a similar appearance occasioned by effusion and organisation of lymph betwixt the deep lamellæ of the cornea, and which is termed _Albugo_.

Albugo occurs during the intensity of inflammatory attacks. It also is surrounded occasionally by thinner opacity, but not depressed and unequal on the surface, as leucoma sometimes is. Large and tortuous vessels are generally seen passing into albugines, but meshes of dilated vessels are seldom present. When the affection is recent, it sometimes disappears under proper treatment, especially in young subjects; but the albugo is by no means so readily removed as the _Nebula_, or thin cloudy opacity which is the frequent consequence of obstinate chronic dilatation of the conjunctival vessels. Nebula is superficial, and consists of mere thickening of the conjunctival covering, from lymph having been effused. It impairs vision, but does not destroy it, for the affected part remains semitransparent.

In strumous constitutions specks of the cornea are often accompanied with ulceration of the edges of the palpebræ, and destruction of the ciliæ—_the ophthalmia tarsi_. The margins of the eyelids are red and slightly tumid, and discharge an acrid fluid; the ciliæ are matted together; pustules form at their roots; the bags which secrete them are laid open and destroyed, and they consequently fall out. The affection is often of long duration, and may be in part prolonged by vitiated secretion from the meibomian glands. During its progress it excites very considerable irritation in the whole eye, and, as has been already stated, opacities of the cornea not unfrequently accompany it. Veins become enlarged, and varicose on the conjunctiva, as also their minute ramifications on the clear part of the ball; small reddish lines appear on the cornea, and around them is “diffused a thin, milky, or albuminous humour,” which destroys its transparency at that part. Such spots may be solitary or numerous, and darken the cornea either partially or entirely. They are always surrounded with a fasciculus of enlarged veins.

In elderly people a dim opaque ring, of a greyish colour, sometimes encircles the margins of the cornea, and is called _Arcus Senilis_; but this can scarcely be looked upon as a disease.

Sometimes the cornea presents a _spotted_ appearance; and this state of the organ is generally attended by obstinate inflammatory action in the part. The affection, however, is rare. I have seen several instances of it: in one, both corneæ were spotted, and sight was almost destroyed, without much irritability of the organ. The disease yielded to external stimulants, and the internal use of the bichloride of mercury. It is met with in a chronic and very intractable form.

The cornea may sometimes be rendered dim by _over-distension_, the aqueous humour being unusually copious.

Occasionally _sloughing_ takes place in the cornea from over-action. It is dangerous to the structure and functions of the organ, according to the extent to which it occurs.

_Ossification_ of the cornea is said to take place; but few cases are on record, and these were in very old people.

The cornea sometimes becomes _conical_ to a great degree in persons considerably advanced in life. The cone has its apex in the centre of the organ, seems thick and crystalline when viewed laterally, and when looked on from the front has a sparkling appearance. In some cases it is opaque in the centre, and occasionally its surface is irregular. Vision of objects at any distance is very indistinct; those placed within an inch or two of the eye are most distinctly seen, especially if looked on through a small aperture. The disease usually affects both eyes, though not always in an equal degree. The patients cannot judge accurately of distance, and see objects multiplied and disfigured.

_Staphyloma_ has been already alluded to as an occasional consequence of purulent ophthalmia in children. The cornea is thickened, prominent, and opaque; and in most cases vision is either much impaired or entirely lost. The prominence varies in different cases, being sometimes very little elevated beyond the natural state of the part, while in other instances it protrudes from between the eyelids. After having attained a certain size it often becomes stationary; but very frequently it continues to enlarge gradually. When the prominence is large, much inconvenience arises from the eyelids not being allowed to close; and the eye, being thereby deprived of its natural covering, is extremely liable to become inflamed from external irritation. When one eye is affected with staphyloma, the other not unfrequently becomes similarly diseased.

Dropsy of the anterior chamber, or _Hydrophthalmia_, occasionally takes place in persons of weak constitutions. The aqueous humour is either secreted in greater abundance than it usually is, or absorption is diminished. The cornea gradually accommodates itself to the increase of the fluid behind, and becomes wider and more prominent, but retains its transparency; in looking at the eye, the anterior chamber is seen evidently enlarged, and occasionally the aqueous humour is of a turbid appearance. There is little or no pain in the eyeball, but the patient complains of an annoying sense of fulness and tension in the part. In consequence of the vitreous humour also accumulating, the whole organ is ultimately enlarged considerably, and its motions are thereby much impeded. At first, vision of near objects is impaired, whilst the patient sees very distinctly those placed at a distance; ultimately sight is entirely lost.

_Exophthalmia_, or protrusion of the eye, attends the preceding disease, and is also a consequence of various other morbid actions in the globe and its neighbourhood, especially from the pressure of tumours in the orbit. The chronic enlargement of the bulb is noticed more fully in the succeeding chapters.

_Treatment of External Ophthalmia, and its Consequences._—The exciting cause, if such exist and can be discovered, ought in the first place to be removed. The surface of the organ and of the palpebræ should be carefully examined, either with the naked eye or with a magnifying glass, in order to detect any small extraneous body which may be lodged in the part. In examining the inner surfaces of the palpebræ, it is necessary, to produce complete eversion, to bring the parts completely into view; and the most convenient method of accomplishing this is to lay hold of the ciliæ between the finger and thumb, and reflect the lid over a silver probe placed along its base. This can, by a little practice, be accomplished readily without using a probe, and even by the fingers of one hand only. This is the more necessary, as small particles of foreign matter lodge more frequently on the palpebral conjunctiva than on any other part. If a particle of glass, metal, stone, &c., be discovered, it should be gently removed by the flattened extremity of a silver probe, or by a scoop, a fine needle, or a delicate brush. In some cases washing the surface by means of a small syringe, filled with a bland fluid, is extremely useful; as when an impalpable powder has been thrown into the eye, and can with difficulty be removed, in consequence of spasmodic contraction of the eyelids preventing exposure of the parts. The application of an emollient poultice, with the addition of hyoscyamus, is beneficial when it has been found impossible to remove the whole of a fine powder. When particles of lunar caustic have, by accident, come in contact with the eye, they are to be removed, as soon after insertion as possible, by a fine hair pencil dipped in oil or fresh butter,—not in water. Small loose bodies are generally carried, by the increased lachrymal secretion, along the sulcus formed by the apposition of the eyelids, to the inner canthus, and there discharged. And, in order to favour this natural process for removing extraneous matter, the patient should be directed to keep the eyelids shut, and as quiet as possible, to cover them with his hands, and to blow his nose forcibly: thus the greater number of the extraneous particles will be got rid of. Those which remain lodged in the membranes must be speedily removed by those artificial means which have been already enumerated. If entropion is the cause of the inflammation, the eyelashes are either plucked out, or completely destroyed by removal of their roots. The inflamed organ should be carefully protected from the stimulus of strong light; the patient is to be placed in a darkened room, and the eye protected by a thin green shade. The shade, however, may be worn too long, so as to induce an extremely weak and tender state of the organ.

If there be good grounds for believing that the incited action has been caused by suppression of any discharge, that should be encouraged to return, and the cause of the suppression must be avoided. If a gonorrhœa have been suddenly arrested by the employment of stimulating injections, these must be instantly discontinued; and some have even gone so far, in such cases, as to introduce bougies impregnated with gonorrhœal matter, in order to procure a renewal of the discharge. In cases of suppression of purulent discharge from the ears, or the surrounding parts, followed by external ophthalmia, a blister or sinapism should be applied in the neighbourhood of the part from which the discharge formerly issued. When the menstrual evacuation has been arrested, leeches and fomentations should be applied to the pudenda, or around the anus, and emenagogues administered internally; the patient should be placed in a quiet and well ventilated apartment, and kept free from any emotions of the mind; all noise and other sources of irritation should be studiously avoided.

If the incited action in the eye do not subside, as it often will not, on removal of the exciting cause, recourse must immediately be had to very active means for its subjugation; for in no other organ does inflammatory action proceed more rapidly to an unfavourable termination. By timely use of antiphlogistic means, those consequences of external ophthalmia, which we have already treated of, may be avoided; and, with respect to most of them, it is much better to prevent their occurrence, than combat them after they have been allowed to take place. The eye is more valuable to a great proportion of people than a limb; and the surgeon is very culpable if he be not master of this part of his profession, and able to undertake the management of every disease and accident to which the eye is liable. “In cases of inflammation the general treatment is the same; but each variety requires peculiar attention during the cure, depending on the structure and function of the tissue affected.”

In the _first stage_ of external ophthalmia, active antiphlogistic measures must be put in force. In full habits, and cases of intense action, general bleeding must be employed, even to fainting, from the veins of the arm or of the neck, or from the temporal artery,—and repeated, if necessary, according to circumstances. Blood is sometimes abstracted by cupping from the temples or the nape of the neck; but it is a painful and uncertain mode of emptying the vessels. Local bloodletting, in many cases, suffices to moderate the action; in all it is most beneficial and important, after the employment of general depletion. The application of leeches to the inner canthus is the most effectual method of abstracting blood locally, as at that point the venous return is made from the eye. If placed on the temples, they can produce very little benefit; if on the outer surface of the eyelids, ecchymosis follows, on account of the extreme looseness of the cellular tissue in that situation. Or the angular vein, at the inner canthus, may be opened with a lancet, and a considerable quantity of blood thereby abstracted from the seat of the disease. Leeches applied to the conjunctiva of the lower lid are sometimes advantageous; but leeching and scarification are more useful in the chronic stage: and the latter is injurious in acute ophthalmia. Saline purgatives, and antimonial medicines, a very material part of the antiphlogistic regimen, must not be omitted. Enemata, with occasional pediluvia, are much recommended by some Continental writers. In bilious habits emetics, followed by mercurial purges, will be found very useful. With respect to topical treatment, warm applications are found to afford decided relief in the first stage, and are, in consequence, generally used. By some, however, cold water, or water with vinegar, is applied from the first. Poultices, whether warm or cold, prove annoying from their weight. Warm fomentations, simple or anodyne, are preferable, and may be repeated according to the feelings of the patient; or the eye may be exposed to the steam of water.

When by these means the violence of the symptoms has abated, as usually happens in the course of a very few days, the organ must be gradually accustomed to its natural stimulus, light. The shade must be discontinued, and the room no longer darkened; and now leeching becomes of great service, while the evacuation is to be followed by gently stimulating or astringent applications, so as to produce contraction of the still dilated, though partially emptied, vessels. Various collyria may be employed for this purpose. Solutions of the sulphate of zinc, of muriate of mercury, of sulphate of alum, of acetate of lead, or of the lapis divinus—wine of opium—the citrine ointment, or the unguentum oxydi hydrargyri rubri, &c.—or stimulating vapours of various kinds. Camphor is a good addition to many of the applications. The collyria may be cold, or slightly warmed; and maybe dropped into the outer canthus, flowing over the eye, and escaping by the inner canthus, according to the natural course of the fluids of the eye; or they may be inserted at the inner canthus, the head being immediately afterwards inclined so as to allow the fluid to pass towards the external canthus; or they may be applied by means of an eyeglass. Warm fomentations, and other relaxing remedies, however useful during the first stage, are worse than useless, are hurtful in the highest degree, when the affection has passed into a chronic state; as also are antiphlogistic means, and exclusion of light,—remedies so essentially necessary in the first stage.

In ophthalmia, attended with profuse _purulent_ discharge, the structure of the eye is in great danger of being destroyed, from the intensity of the action, and its liability to extend to the deep parts of the organ; the most active practice is required from the first. Copious general depletion, ad deliquium, must be quickly had recourse to; and the patient must be freely purged, and kept in a state of partial nausea for some time, by exhibition of antimonials. After general bloodletting, the repeated application of leeches to the inner canthus is necessary, in order to empty sufficiently the vessels of the part. Where the chemosis is so extensive as to bury the cornea, as it were, beneath the folds of the swollen conjunctiva, sloughing of the transparent tunic is frequently threatened. In order to arrest this fatal result, much good is often obtained by division of the chemosis. A sharp-pointed bistoury is passed through the swollen membrane, and radiating incisions practised, commencing at the corneal margins, and directing them towards the circumference of the globe. Sometimes four or even five of such divisions are called for, while care is taken not to wound the sclerotic coat beneath. A considerable quantity of blood is sometimes lost by this procedure, and, the chemosis subsiding, the cornea is saved. Infusion of tobacco, solutions of acetate of lead, and nitrate of silver, æther and laudanum, have been used as applications to the eye from the very commencement of the affection; but the propriety of the practice appears very questionable. Blistering the nape of the neck proves highly beneficial, after the employment of the antiphlogistic measures; and in many cases it is necessary to keep up discharge from the blistered surface for some time. On subsidence of the violent symptoms, the swelled conjunctiva is to be attacked with escharotics and stimulants, as the nitras argenti, sulphas cupri, or various collyria: then only can such applications be advantageous; at an earlier period they must do harm. They repress the exuberant granulations which may have formed, or may be forming, on the conjunctiva of the eyelids, promote contraction of the dilated vessels, diminish the relaxation of all the tissues, and stimulate the now dormant action of the part into a healthy state of excitement. Gently stimulating collyria may be injected betwixt the lids, by means of a small syringe. In granulated conjunctiva, it is sometimes necessary to remove a greater or less part of the diseased membrane by escharotics, the knife, or scissors; and after this has been accomplished it is well to encourage bleeding to a slight extent. In removing part of the palpebral conjunctiva, care must be taken to avoid injuring the cartilage of the tarsus; and, in the lower lid, not to take away too large a portion, lest entropion should occur during cicatrisation. In hospital practice, the infected should be separated from the healthy; and promiscuous use of towels and sponges must not be allowed.

In _Purulent Ophthalmia of Children_, antiphlogistic means must be pursued, if the patient is seen during the first stage of the disease; but children do not bear depletion well. After the discharge is established, the surface of the eye must be kept free of matter, by frequent injection of a bland, tepid fluid; and stimulating or astringent collyria should be applied three or four times a-day.

When _Inflammation of the Cornea_ is established, it is exceedingly difficult to procure contraction of the vessels. Active antiphlogistic measures must be employed in the acute stage; and in the chronic, stimulant applications are to be had recourse to. As, however, corneitis is frequently kept up in its chronic form, from deficient constitutional power in strumous habits, strict attention must be paid to the diet and secretions of the patient. Mild mercurial alteratives, diaphoretics, and tonics combined, will often effect a cure, where all local treatment has been tried in vain. When a large plexus of vessels remain dilated on the part, the most effectual method of removal is to divide them, as they ramify on the sclerotic, by means of scissors, or a fine knife, and afterwards to employ stimulating applications.

The irritability of _ulcers_ on the cornea is diminished by the application of nitrate of silver, in solution or substance. If in solution, the application is used in the proportion of three to ten grains of the salt to the ounce of distilled water; if in substance, a portion, finely pointed, is gently applied to the sore, which may be afterwards besmeared with a little oil or simple ointment, in order to confine the action of the nitrate to the ulcerated part. It is not necessary, but, on the contrary, hurtful, to rub the caustic freely on the sore; a very slight application is sufficient to coagulate the secretions on the part, and form a covering for protection of the surface. In two or three days afterwards, when the temporary covering has become detached, and when the irritability of the sore has in consequence returned, it will be necessary to repeat the application, but not till then. On each application, and few are in general required, the sore is found reduced in size considerably. The collyrium nitratis argenti is very useful in many obstinate cases of affections of the eye and eyelids, the strength of the solution being varied, according to circumstances.

In _Albugo_ and _Leucoma_, proposals have been made for excising, scraping, or perforating the opaque part; but the cure by such means is worse than the disease, as a raw surface is left larger than the previous opacity, and the cicatrix which must inevitably form also occupies a larger space, and is equally opaque. Leucoma and Albugo are incurable diseases, though the opacities may become somewhat thinner, by natural processes, after the lapse of a long period. _Nebulæ_, however, are often removable. During the treatment of them, or, rather, before beginning to treat them, it is of the utmost importance to attend to the state of the surface of the eye, and of the lids and eyelashes. Stimulating substances may be applied in cases where the opacities are thin: powders of calomel, aloes, sugar, &c., have been blown into the eye; stimulating lotions or ointments are preferable; one containing the nitrate of silver, with the addition of a proportion of the liq. sub-acet. plumbi, is sometimes used with advantage. These, however, are often of no avail, unless the dilated vessels, when such exist, are divided, or a portion dissected out; afterwards stimulants will be efficacious, and must be used assiduously. The vessels may require to be divided again and again.

In _Ophthalmia tarsi_, gently stimulating ointments or lotions are to be used, and in obstinate cases much advantage will result from the application of blisters behind the ears and to the nape of the neck, or from the insertion of a seton in the latter situation. In children it is necessary to correct the state of the bowels, scarify teeth, and remove other irritating causes to which that tender age is liable.

_Sloughing of the Cornea_ should, of course, be prevented, if possible, by subduing the incited action before it has attained such intensity as to overcome the power of the part. The slough is slow in separating when the constitution has been much weakened; and sometimes tonics and stimulants, both external and internal, are required to hasten the process of separation. When the surface has at length become clean, the same treatment is required as to an ulcer of the part.

_Conical Cornea._—This deformity can scarcely be cured, nor can any optical contrivance effectually remedy the disturbance of vision. When the apex of the cone is opaque, the removal of the pupil to the circumference by operation affords the best chance of assisting the sight of the patient.

When _staphyloma_ is small, neither impeding the motions of the eye, nor preventing its being protected by the lids, no surgical interference is called for, as the loss or impairment of vision cannot be remedied, and as no other inconvenience than blindness is produced by the change of form in the part. But when the diseased cornea projects from between the eyelids the prominence must be diminished, on account of the deformity which it occasions, and in consequence of the eye being deprived of its natural protection of the lids, and being thereby exposed to constant irritation. In such cases it is necessary to take away a portion of the cornea, that the eye may be so diminished in bulk as to retract within the eyelids; the size of the part removed must be proportioned to the degree of protrusion. A cornea-knife is passed into the prominence, and carried forwards so as to transfix the part, in a direction from the external to the inner canthus; and by the knife being carried on, with its cutting edge looking downwards, a flap of the cornea is made. This flap is then laid hold of by means of forceps, and removed either with the knife or with scissors. The aqueous humour immediately escapes, and in most cases the crystalline lens and vitreous humour are also discharged. The eye consequently shrinks, and retracts within the palpebræ. The cut margins of the cornea soon assume a reddish appearance—they form granulations, the wound contracts gradually, and ultimately closes; but the eye is necessarily much shrunk, and totally useless as an organ of vision. Generally suppuration takes place, causing complete disorganisation of the parts; and the preceding inflammatory action may be so intense, and attended with so much constitutional disturbance, as to require active measures for its moderation. Deformity may be in a great measure removed by adapting an artificial eye to the shrivelled remains of the natural one. When it is necessary to remove only a small part of the cornea, the aqueous humour alone escapes, and during the cure of the wound the patient not unfrequently enjoys a tolerable degree of vision; but after the wound has completely closed, vision is again lost completely.

_Hydrophthalmia_, also, is a disease in which little hope can be entertained of materially benefiting the patient. In the slighter cases, in which no very annoying symptoms accompany the affection, vision may be improved by the use of optical instruments; mercurial preparations may be employed in moderation, with the view of promoting absorption of the superabundant fluid. When the disease has made considerable progress, temporary relief may be obtained from puncturing the cornea at its lower part, so as to discharge the accumulated aqueous humour; but a cure can scarcely be expected from such a practice, however often the paracentesis may be repeated. In the worst cases the pain is so excruciating, and the system so much disturbed by the local affection, as almost to warrant the destruction of the organ, in order to relieve the patient; but, after all, even such severe measures will most probably prove unavailing.

In _Exophthalmos_ the treatment must vary according to the circumstances which cause the protrusion of the eyeball.

_Of Internal Ophthalmia._—Inflammation of the internal parts of the eyeball sometimes supervenes on conjunctival inflammation, and then the distinctive characters of the two affections are not perceptible. When inflammatory action attacks the deep parts primarily, the external ciliary vessels ramifying on the sclerotic coat are seen, enlarged, shining through the conjunctiva; and, as they advance towards the clearer part of the eye, they form a zone of a pink colour, whose vessels run in a straight direction towards the margin of the cornea; but between the zone and the cornea a distinct white line is often interposed. Then large arborescent and reticulated vessels soon appear on the white part of the eye; and from their being more superficial than the first, and of a brighter hue, it is obvious that they belong to the conjunctiva. They also approach the clear part of the eye, and, if numerous, obscure the former vessels—as also the red zone and white line—for they pass over them, and reach the corneal margins, and often go beyond it, in continuous ramifications. The sclerotic, in consequence, assumes a pink-red colour, and the cornea becomes dim.

The iris may be primarily and principally affected, and, if so, the disease is termed _Iritis_; but in most cases all the other internal parts suffer more or less. The iris changes its appearance, becomes of a dusky hue, either in part or throughout, and red vessels are sometimes distinctly seen in it; from grey or blue it changes to a greenish colour, and when formerly black or brown it becomes reddish. The size of the pupil diminishes, and the contraction is often irregular, when the inflammatory action is intense. The iris swells perceptibly, and the pupil loses its dark colour, or is almost entirely closed, either from effusion of lymph, or from inflammation and consequent opacity of the crystalline lens and its capsule. The iris projects forwards, and diminishes the capacity of the anterior chamber; the pupil is irregular, and often assumes an angular appearance; and the irregularity becomes permanent from adhesion of the pupillary margin of the iris to the capsule of the lens, lymph being effused and organised, and forming a firm uniting medium between the parts. Occasionally adhesions form at the middle of the iris, and cause so great contraction as to give the pupil an appearance of being double. Of course irregularities of the pupil are most distinct when the part is dilated, either spontaneously or by the application of belladonna. Tubercles sometimes form on the iris, and not unfrequently it presents a granulated appearance. From the commencement of the inflammatory attack the patient feels great pain in the organ and in the forehead, and there is great intolerance of light. There is a feeling of tension of the eyeball, followed by deep throbbing pain increasing every instant. As the disease advances, the cornea is rendered opaque by the fulness of the chambers, and the aqueous humour becomes turbid and of a milky appearance; or lymph is effused into the anterior chamber, and floats about in flaky portions. Occasionally the vessels of the iris are so distended as to give way, causing effusion of blood into the chamber, often in considerable quantity.

More frequently, however, puriform fluid is deposited, occasioning the appearance termed _Hypopium_. The pus is either fluid or of a thick curdy consistence: when fluid and thin, it mixes with the aqueous humour, rendering it white and opaque; if of firmer consistence, it lodges in the lower part of the chamber, but changes its position, and mixes partially with the humour, on the head being moved; when dense and curdy, it remains separate from the humour, and its position is not altered by motions of the head.

During the progress of the inflammatory action, all the symptoms increase; the pain shoots to the top of the head, and is much aggravated by pressure on the eyeball. Of course vision is materially impaired. Constitutional disturbance always accompanies the affection, and exists in a greater or less degree according to the extent of the disease. The iris may be primarily affected, but the other textures, both external and more deeply seated, too often become involved; and in aggravated cases the whole eyeball suffers. When the most internal parts, as the choroid coat, the retina, and the vitreous humour, are affected, sudden and bright flashes of light disturb the patient, whilst vision is rapidly lost, and for ever. Occasionally the intense over-action terminates in suppuration of all the affected textures, and the eyeball soon becomes completely disorganised.

In _Rheumatic Ophthalmia_ the appearances of the diseased eye are similar to those in ophthalmia produced by any other cause. But the affection is accompanied with, and seems to arise from rheumatic diathesis. There is pain in many of the joints, and frequently in the scalp and portions of the face, increased on hanging the head, and by pressing the parts. The pains are remittent, supervene at night, and subside in the morning. In general the ophthalmia is external; but in severe cases the internal parts become affected, and the eye is sometimes lost by giving way of the cornea.

Internal ophthalmia is often occasioned by wounds inflicted either accidentally or by operation. Laceration of the iris in the extraction of cataract, or an improper performance of the operation for cataract with a needle, is by no means an unfrequent cause of the affection. Iritis often occurs during the exhibition of mercury in undue quantities, and is said also to be a symptom of syphilitic taint. It is, in many cases, preceded by cutaneous eruption, and seems to be the consequence of the eruption being repelled, or interfered with in its progress.

_Choroiditis._—The choroid membrane is sometimes primarily affected: but more frequently the inflammation of this tunic is the consequence of sclerotitis, or the disease last described. When the result of the former cause, it generally takes on the rheumatic type. The early symptoms are zonular redness of the sclerotic, accompanied by a general impairment of vision, so that the patient expresses himself as if looking through gauze or some dark network. Presently the sight becomes more and more impaired, until a complete amaurosis results. The pupil is generally in a semi-dilated state, and, instead of presenting the intense black hue of the healthy eye, it reflects a greenish-grey colour, dependent upon the effusion of a turbid fluid between the choroid and retina. The nervous structures, becoming thus pressed upon, lose their sensibility to light, and are paralysed. This form of inflammation is generally chronic, and imperceptibly advances to the iris anteriorly, and to the retina within; the ultimate termination being complete glaucoma. Various dull and heavy pains accompany this affection; and, in the latter stages, acute circum-orbitar neuralgia is the most distressing concomitant. By long-continued chronic inflammation the sclerotic coat appears to lose its powers of resistance—the accumulating fluid pushes before it the weakened tunic, and _Staphyloma Scleroticæ_ is produced. This protrusion of the external tunic sometimes takes place in various parts, and to a considerable extent, so that the figure of the globe is entirely lost. The thinning of the sclerotic at these points allows the dark hue of the choroid to shine through, and this, together with the bunched-like appearance of the protruded portions, has entailed upon it the name of _Staphyloma Racemosum_.

_Treatment._—In the first stage of internal ophthalmia, active treatment, properly conducted, should be successful in averting the progress of the disease; in the latter stages, there is every chance of vision being entirely lost. The treatment must be actively antiphlogistic, consisting of general and local bleeding, the internal use of purgatives and antimonial medicines, and strict abstinence. A free use of mercury internally is said to check the disease, and, in its advanced stages, to procure absorption of effused lymph. But the inflammation can be subdued without the aid of that mineral, though its effects are often powerful; and a recollection of the bad effects which are so apt to follow its employment renders a prudent surgeon cautious in having recourse to it. Mercurial ointment, with opium, rubbed on the forehead, immediately above the affected eye, gives great relief. The same relief follows friction with oil, in which the muriate or other salts of morphia is dissolved. When the incited action declines, the extracts of belladonna, hyoscyamus, or stramonium, rubbed on the eyelids and brow, procure dilatation of the pupil, and thereby tend to prevent its further contraction; but whilst acute inflammation exists, the pupil is not dilatable; and it is consequently an encouraging symptom when the pupil begins to yield to the influence of these medicines. In hypopium it is sometimes necessary to evacuate the pus when effused in large quantity, in order to prevent the injurious effects that its pressure might occasion; but, if the quantity be small, there is a good chance of its being removed by absorption. In suppuration of the eyeball, whilst the other eye remains sound, it may be prudent to open the cornea, and allow a free exit for the matter, in order to prevent the healthy eye from becoming affected. In the staphyloma of the sclerotic coat, when the eye, as it were, is affected by a sort of chronic dropsy, (and this disease is met with at various periods of life,) the tension and bulk of the organ may be diminished by occasional puncture. The opening may be kept pervious by the introduction of a conical probe from time to time. I have more than once introduced a silk thread through the most dependent and prominent part of the globe with good effect. The organ ultimately shrinks.

_Amaurosis_ implies an impairment of vision more or less complete, arising from disease in the brain, in the optic nerve, or in the retina, whether consisting of change or destruction of structure, or derangement of function. Vision may be diminished or lost by organic disease in the coats or humours of the eye, or by morbid formations in the orbit; but to such the term Amaurosis does not strictly apply. But, after establishment of the disease, other textures of the eye may, and often do, become affected. Usually one eye at first is amaurotic; but the other soon participates, and ultimately vision is impaired or entirely lost in both. The disease may occur idiopathically, or be symptomatic of other affections.

The general symptoms of amaurosis are the following. Headache is felt for some time, either constant, or, as is most commonly the case, occasional, and most severe in the forehead: in many cases the pain is at times most excruciating. The eyesight gradually becomes weak; distant objects are unusually obscure, or not at all observed; and those which are near cannot be accurately discerned. For a short time vision may seem to be restored, but soon it diminishes more and more, all objects seem to be enshrouded in a mist, at first thin and shadowy, but gradually becoming opaque and impenetrable; or a feeling is communicated of a dark network obstructing the view. Unnatural impressions are made on the retina; flashes of strong light, or luminous sparks, appear to dart across the eyes; darkened spots are seen where none exist; gnats, flies, or other minute bodies, various in colour and brilliancy, seem to flutter before the face; or a single dark speck intercepts the vision. Usually the pupil is dilated and the iris insensible to the stimulus of light; and the former has not its natural translucent aspect, but is dull and cloudy. But the state of the pupil cannot be accurately determined in amaurosis, for not unfrequently it is much contracted, and in many cases the iris retains both its natural appearance and the full exercise of its functions. The disease either advances to complete blindness, or stops in its destructive progress, leaving the patient with vision impaired to a greater or less degree. When the disease is established, pain in the head and eyes usually either ceases quickly and entirely, or gradually abates.

Amaurosis is sometimes temporary, occurring at regular intervals; and, during its accession, it often varies in intensity. With some patients strong light is intolerable, and vision is best in the twilight; others court sunshine, finding their eyesight thereby much improved; accordingly the former are said to labour under nyctalopia, the latter under hemeralopia. Some can discern the shape of objects, but either have no perception of the colours, or mistake the individual colours; others not only see all objects indistinctively, but conceive them distorted, double, or extensively multiplied: in some one-half of the object looked upon is obscured—and frequently there is strabismus, in consequence of the paralysis being only partial.

Organic amaurosis (that depending on organic disease) may arise from the change of structure consequent on inflammatory action in the retina, whether chronic or acute—from atrophy of that membrane and of the optic nerve—from extravasation into the substance of the nerve, or compression of it by morbid formations—from softening or suppuration of the nerve and its connexions—or from various diseases of the encephalon. Functional amaurosis may proceed from temporary plethora about the optic nerve and retina—from intense and long continued use of the organ—from derangement of the digestive apparatus—from general debility, however induced—from excessive influence on the system of poisons or powerful medicines—from concussion of the nervous and cerebral substance, or from long continued irritation in the neighbourhood of the eye. Amaurosis may also follow injuries of various kinds.

In the treatment of organic amaurosis but little can be done, and that little is unsatisfactory. In the functional form, however, vision may be improved, if not wholly restored, by removal of the exciting cause, and the carefully avoiding of such circumstances as seem to predispose to the affection. After due constitutional treatment, considerable benefit is often derived from counter-irritation; and I have in many cases witnessed the good effects of blistering the temples and besprinkling the raw surface with the powder of strychnine,—a practice very far from nugatory. On removing the blister, the cuticle and lymphatic effusion beneath are carefully scraped away, and from one-eighth to one-half of a grain of the powder dusted over the exposed cutis. The sprinkling is repeated daily, and the dose gradually increased. When the surface dries, a fresh blister is applied, and the use of the powder resumed. It may be employed, when gradually increased, to the extent of two grains on each temple; but, if spasmodic twitchings and constitutional disturbance begin to show themselves, it must be immediately abandoned, and not resumed till after some days, and even then in diminished doses. In not a few cases, both of complete amaurosis, and of vision impaired to such an extent that the patient could merely distinguish light from darkness, I have by this practice succeeded in restoring the sight completely; in others, vision has been very much improved. Still, by far the greater number of amaurotic patients are incurable; and even those who have derived benefit from strychnine are, I am strongly inclined to suspect, exceedingly liable to relapse.

In the treatment of functional amaurosis, it will be necessary to investigate minutely the causes on which the defective vision may depend. Thus we may find a congestive state of the retina or brain, arising from suppressed natural discharges, as the menstrual flux, or the sudden suppression of habitual but morbid discharges, as the healing of an old ulcer, &c.

Again, amaurosis maybe the result of irritation in some portion of the alimentary canal, as from the presence of worms. Patients who have long laboured under imperfect amaurosis have occasionally been suddenly relieved by the discharge of a tape-worm. Difficult and painful dentition in children not unfrequently gives rise to this disease. Hence the treatment of functional amaurosis will necessarily vary with the cause; and no general rule can, with any propriety, be laid down as to our selection of remedial measures.

_Glaucoma_, or green cataract, is a disease of the hyaloid membrane and vitreous humour, probably depending on a varicose state of the bloodvessels. The pupil is usually dilated, irregularly oblong, the iris being narrowed towards the upper and inner side. There is a dull shining appearance at the bottom of the eye, not fixed as in cataract, but varying according to the position of the light. The lens becomes opaque and greenish as the disease advances, vision gradually diminishes, and the iris is immovable. After sight is lost, the patient has a perception of a luminous appearance in the organ when pressed upon. Both eyes are generally affected, one after the other; headache, often violent, attends the disease; many remedies, both external and internal, may be tried on recommendation, though without effect: the disease seldom, if ever, admits of cure.

_Of Cataract_, or opacity of the crystalline lens and its capsule, attended with partial loss of vision.—The disease is, in general, gradual in its progress: but sometimes it advances rapidly, as when occasioned by a blow or wound. When slow, the opacity commences in the centre of the lens, and extends gradually towards the circumference. Before any change can be perceived in the organ, the patient sees objects as if covered with a mist or veil; and, as the opacity becomes distinct, vision is gradually impaired. During the day, vision is very indistinct, as the pupil is contracted, and the rays of light reach the retina only through the opaque centre of the cataract. But during twilight vision improves, as then the pupil becomes dilated, and admits of transmission of light through a portion of the transparent vitreous humour, as well as through the semi-opaque margins of the crystalline lens: for a similar reason, it is also more distinct after the application of belladonna or hyoscyamus either to the eye or to its neighbourhood. In the ordinary state of the parts, a clear black ring is often visible around the opacity, either from the margins of the lens being unaffected, or from the posterior surface of the pupillary portion of the iris being pushed forwards by enlargement of the lens. Patients, having become aware of the great improvement of vision caused by dilatation of the pupil, are often contented to use narcotic remedies externally, so long as they retain their dilating influence—and, strange to say, they do not soon lose it—instead of submitting to any operation. As cataract advances, even luminous bodies cannot be accurately distinguished, though the situation from which the light proceeds is perceived; thus the patient in a clear light may have an indistinct perception of a candle or window, and in some cases even of the bars of the window. The motions of the iris are not affected, unless, in rare cases, when the cataract is large and compresses the iris; or when the functions of the third pair of nerves have been in any way impaired; or when the iris has been the seat of acute inflammation.

Cataract may be confounded with other diseases of the eye, as with amaurosis. But, in amaurosis, opacity, when it exists, is deep, concave, greenish, or of a metallic appearance; whereas, in cataract, it is of a more or less white colour, convex, and situated immediately behind the pupil.

Cataract may be _lenticular_ only, the lens being opaque whilst its capsule remains transparent. In such a case the disease is slow in its progress, and the opacity uniformly commences in the centre of the lens, and gradually extends to the circumference. The degree of opacity varies in different cases, from cloudy dimness to complete whiteness. In general the predominant hue is white or greyish, but not unfrequently the opacity is of several colours, and occasionally of a mottled appearance. The consistence also of lenticular cataract varies, being sometimes fluid, occasionally extremely dense and almost osseous, but most frequently of caseous consistence. When fluid, the cataract is of larger size than the healthy lens; when caseous, the part usually retains its former dimensions; and when dense, the lens is often considerably diminished in size. The motions of the pupil are seldom, if ever, affected.

Cataract may be entirely _capsular_, the capsule being opaque, whilst the lens either remains free of disease, or has been removed by natural or artificial processes. The opacity in this case does not always commence in the centre, but frequently begins at the margin, and is of a spotted or mottled appearance, and in general not uniformly opaque. No black ring around the opacity is observed, though the pupil be dilated; and the motions of the iris are sometimes slow. The opaque spots are said sometimes to move when the position of the head is changed. The anterior portion of the capsule, the posterior, or the whole, may be affected; but the anterior is the part which most commonly becomes opaque in the first instance.

In many cases both lens and capsule are affected; and then the cataract is termed _capsulo-lenticular_. Occasionally the diseased lens, in such circumstances, is of fluid consistence; and in many cases is spotted.

Portions of lymph, organised or not, lodged in the posterior chamber, have by some been termed _spurious_ or _adventitious_ cataract; since, when the pupil is shut by such effusion, the appearances presented are somewhat similar to those caused by opacity of the lens, or of its capsule. Such deposits, however, can readily be distinguished from true cataract, being in general of a yellowish colour, in close contact with the posterior surface of the iris, and, when organised, often streaked with red vessels. Generally, too, the pupil is irregular from adhesions between the lymph and the pupillary margin of the iris.

Cataract would, in some cases, appear to be hereditary,[27] and frequently it is a congenital affection. In very young children it may be caused by imprudent exposure to strong light. In adults it often seems to be produced by the action of strong reflected light, as by exposure to intense fires in forges, glasshouses, &c., or by a dependent position of the head, accompanied with exposure to light. People advanced in life are most subject to the disease.[29] It is not an unfrequent consequence of internal ophthalmia, and almost invariably follows the slightest wound or most delicate puncture of the lens: it often occurs after slight injury of the lens or its capsule, inflicted during attempts to form an artificial pupil. Cataract may occur rapidly from extensive dilatation of the lenticular vessels; or from such an injury of the eye as causes laceration of the vessels supplying the capsule and lens, detaches them from their other connexions, and consequently leaves them without a nutritive source.

Cataract sometimes, though rarely, disappears spontaneously, being absorbed; but most frequently an operation is required to remove the opaque body from the axis of vision, though no hurry is necessary in having recourse to it. The chance of success from operation must depend very much on the state of the different parts of the eye, on the kind of cataract, and on the state of the constitution. Many remedies, external and internal, and mercury amongst the rest, have been employed with the view of dissipating cataracts; but all are of no use. An operation, of one kind or another, only can be relied on. And still, even in favourable cases, and in the best hands, the contingencies attending operation are so great, that success cannot be absolutely promised or expected. The mode of operating, and the kind of operation, must be varied according to circumstances; and great experience is required to determine the proper course of procedure in each case. Steadiness is absolutely necessary both in the patient and the operator, in order that the proceedings may be carried to a happy conclusion. The operator must have a good eye; a steady, light, and skilful hand; a fine touch; courage and caution—qualifications necessary in all surgical operations, and in none more so than in those on the eye.