Text book of veterinary medicine, Volume 3 (of 5)

by James Law

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.