Part 81

Symptoms and lesions. In the simplest form the bulb is displaced forward out of the orbit and through the palpebræ which latter contract spasmodically behind it and effectually prevent a spontaneous reduction. The optic nerve, muscles, and vessels are unduly stretched and the circulation in the bulb is seriously impaired, so that even in the least complicated cases any undue delay in reducing the dislocation will lead to serious and destructive changes in the eye. Sphacelus of the globe is not uncommon under such conditions.

In the more complicated cases, the conjunctiva, palpebræ, nictitans, muscles, nerves, etc., maybe more or less lacerated and the globe itself may be seriously damaged either by internal lesion or by an external trauma. In all these cases there is most imminent danger of general infective inflammation of the eye, of panophthalmia, and even of secondary general infection of the system. Fracture of the bones of the orbit may also be looked for.

Treatment. When dislocation is uncomplicated and recent, say of a few hours standing only, it may be reduced and a favorable issue secured. The bulb should be first washed with water which has been sterilized by boiling or rendered antiseptic with sublimate (1 ∶ 5000), and can usually be pressed back by steady uniform pressure. The insertion under one lid of a small spatula bent at the end or the one limb of a lid speculum may assist in difficult cases. When replaced the parts may be again washed with antiseptic solution and covered by a bandage wet with an astringent collyria.

When the condition has been neglected for a day or more the bulb is congested and swollen so that its return is rendered much more difficult, and its subsequent retention may require much care and ingenuity. The reduction of the turgid globe may be assisted by opening the veins and arteries on the sclera, by astringent applications, by massage, and in obstinate cases by evacuation of a portion of the aqueous humor, by the aid of a fine aseptic needle. Finally the palpebral opening may be enlarged by incising the outer canthus with a probe pointed bistuory. When the eye has been replaced in its socket this must be closed by suture. For the retention of the eye in such cases a bandage may suffice, or this failing, the lids may be held together by strips of adhesive plaster, or by collodion. In very difficult cases Lafosse and Trasbot recommend sutures through the skin 1½ to 2 inches from the palpebral borders and the whole covered with a bandage impregnated with an antiseptic and astringent collyrium.

It is not requisite to keep the bandage in position for over four or five days as the swelling of the eyelids and other adjacent structures effectually prevents any tendency to repetition of the luxation, and the eye may be treated like an ordinary traumatic lesion.

At the outset, and later if need be, any foreign body in the orbit should be removed and any detached pieces of bone which cannot be retained firmly in position, and which are liable to prevent healing or to determine infection of the wound.

In the worst cases and in those that have been neglected until gangrene or panophthalmitis threatens, the removal of the eyeball may be the only resort. The animal may be anæsthetized by chloroform or ether, or locally by cocaine. The conjunctiva covering the sclera is then pinched up with forceps and cut through with scissors, this is continued all around the globe. Then the recti muscles, the superior and inferior oblique muscles, the retractor and finally the optic nerve are cut through with a pair of scissors curved on the flat. The divided ends of the muscles are now sutured together around the nerve which has been cut shorter, and the cavity irrigated by a cold antiseptic solution. Bleeding vessels may be twisted through with forceps if the flow is not readily checked by cold irrigation. Or a pledget of cotton dipped in tincture of muriate of iron may be loosely inserted (firm pressure would be unnecessarily painful). As a subsequent dressing, standard sulphurous acid solution, glycerine and water in equal proportions, or other antiseptic dressings may be applied.

ARTIFICIAL EYE.

These are largely in use in the human being, and have been employed in the lower animals in different cases, especially in the horse, with excellent effect. The advantages may be summed up in this, that they do away with the unsightly appearance of an empty orbit with the edges of the lids turned into the dark aperture, enhance the value by restoring the face to nearly the natural appearance, and prevent the lodgment of dust and insects in the cavity.

The artificial eye may be made to appear more natural if made of glass, yet when made of horn or still better of hard rubber, colored like the normal iris and pupil, it has the advantage of greater lightness. It must be perfectly smooth so as to cause no discomfort, and should never be introduced so long as there is any irritation in the stump or conjunctiva. It may be slipped in like a button, first beneath the deeper upper lid, and then beneath the lower, and should be worn only while at work and so long as it causes no irritation nor purulent discharge. On the return of the animal to the stable, the artificial eye is taken out, washed and placed in clean pure water. The orbit should be sponged out with a weak collyrium (boric acid 1 ∶ 100).

In man, excentration is sometimes substituted for enucleation, the cornea is removed together with the lens, vitreous, choroid and retina, leaving only the sclera which contracts into a dense scar tissue with the muscles attached. Or an artificial vitreous of glass or unoxidizable metal is introduced around which the sclera is allowed to heal. This introduces an additional element of danger over the formation of a simple sclerotic stump, but, when successful, it affords a better support to the artificial eye, turning it freely in harmony with its fellow and giving it a more natural aspect.

STRABISMUS. SQUINTING. LACK OF MUSCULAR BALANCE.

Causes: paralysis of eye muscles, bulb rolls from affected muscle, spasm of eye muscles, bulb rolls toward affected muscle, convergent squint most common. Hold head still and move object in front of eyes, imperfect movement toward paretic muscle or away from the spastic one. Ptosis. Overfatigue. Debility. Nerve or brain lesion. Dislocation of bulb. Treatment: treat any transient etiological factor, cerebral congestion, parasitisms, debility, anæmia. Tenotomy of rectus: advance of paretic rectus.

Strabismus may be due to a variety of causes, among others to the following:

=Paralysis= of one of the ocular muscles. When the eyes are turned in the direction away from the affected muscle the muscle is deficient in power. It may be the external rectus (abducent nerve) producing convergent squint. It may be of the superior oblique muscle (4th or pathetic nerve) causing a faulty movement of the eye downward and inward or a slightly convergent squint. Divergent squint commonly indicates paralysis of upper, lower and inner recti, and the inferior oblique (3d or oculo motor nerve): this is usually associated with ptosis or drooping of the upper lid, the levator of which is supplied by the same nerve. The existence of squint is usually so marked that no special method of examination is required. If otherwise, however, the animal’s head may be held still and some object which will attract his attention is moved before the eyes, outward and inward, when the affected eye moving in the direction of the paralytic muscle will lag visibly behind its fellow. These conditions are usually due to lesions in the respective nerves or their cerebral ganglia.

=Spasmodic or Spastic Squint= is the exact antithesis of the above, the eye turning toward the muscle which is the seat of spasm. It may be seen in certain cases of rabies and is always due to disorder of the central nervous ganglia.

In some cases squinting is associated with over-fatigue, or debility, and then usually partakes of the paralytic character.

In the lower animals convergent strabismus has been most frequently observed. Brouwer records a case in the horse and Koch a congenital one in the cow. Zschokke reports a case in the cow connected with an angioma at the base of the brain. Other forms are noted by Peters, Barrier, Bayer and others. Stockfleth quotes a case in the dog following prolapsus bulbi and doubtless connected with injury to ocular muscles or nerves, sustained in the accident.

Treatment will vary with the ascertained cause. As a rule cases that depend on structural changes in the brain are hopeless. Those that depend on temporary congestion or other transient disorder of that organ may recover when that has been overcome. In cases in which debility is a prominent feature, tonics, moderate exercise in the open air and general hygienic care are demanded. The final resort in bad cases is tenotomy of the rectus on the side toward which the eye turns. In man when this is found to be insufficient the opposing weak or paretic muscle is also advanced. The tendon close to its sclerotic attachment is laid bare by incision, and a silk or catgut thread is passed through each border, upper and lower. The tendon is now cut through with scissors on the corneal side of the sutures and, by means of their needles, the latter are passed through the conjunctiva and capsule of Tenon, from within outward and close to the margin of the cornea. The sutures are now tied somewhat tighter than is absolutely necessary to properly balance the eye so as to allow some room for relaxation in healing. We are not aware that this measure of advancement has been employed in the domestic animals.

NYSTAGMUS. OSCILLATORY MOVEMENT OF THE EYE.

This consists in spasmodic involuntary oscillation of the eyeball in a horizontal, lateral, oblique or rotary direction. In animals it has been seen in connection with poisoning and brain diseases. Johné has observed it in horses in cerebro-spinal meningitis, Wenderhold in epilepsy, and Möller in chloroform anæsthesia. Möller has further seen it in puppies with congenital microphthalmos, and Siedamgrotzky in swine which had been poisoned by herring brine.

Slight cases of functional disturbance may improve under good hygiene, open air life and tonics, cases due to poisons may recover spontaneously when such poisons have been eliminated, but those which depend on structural disorder of the brain are beyond remedy.

DISEASES OF THE SKIN.

Ultimate skin lesions in man and animals similar. Masked by thick cuticle, pigment, hair, fur, feathers. White, hairless skin. Lesions and deranged functions: Maculæ, erythema, papules, nodules, blisters, blebs, pustules, boils, carbuncles, scales, crusts, sitfasts, horny growths, erosions, abrasions, chaps, fissures, ulcers, excrescences, cicatrices, neuroses, morbid secretions, changes in glands, hairs, in derma. Scleroderma. Elephantiasis. Vegetable and animal parasites.

In cutaneous diseases in man and animals the actual lesions are largely of the same nature, yet in the animal covered with hair, fur or feathers, and with the cuticle deeply pigmented, the diagnosis of the different affections becomes much more difficult. On white-skinned animals and on parts with little or no hair, the identification of the different forms is usually possible. The following list may serve to indicate the nature of the different lesions, but these must not be accepted as indicating distinct diseases, as two or more of these forms often coexist or succeed each other in the same affection:—

1st. =Maculæ: Spots: Discolorations.= Examples: Black, melanotic spots in skins of white horses: white spots in dourine, after pustules, etc.: ecchymosis after contusions, stings, insect bites, etc.: petechial spots in anthrax, rouget, hog cholera, rinderpest, canine distemper, swine plague, scurvy, etc.

2d. =Erythema: Rash: Flush.= Congestive redness usually disappearing under pressure. Physiological in blush or glow of exercise, pathological from insolation, friction, deranged innervation, etc.

3d. =Papulæ: Papules: Pimples.= Small, red, hard, conical elevations, not forming blister nor pustule. Due to exudation and the accumulation of leucocytes at given points, having a local or general cause, (psoriasis, intertrigo, etc.).