Part 28

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, 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. 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.