Part 69

Causes: harness, whip, nail, hay, straw, stubble, thistles, spikes, twigs, pine needles, cones, burdocks, stones, gravel, glass, splinters of wood or metal, scratches, stings. Symptoms: closed lids, epiphora, sight of lesion, soon cloudy swelling, opacity. Treatment: antiseptic bandage and lotion, boric acid, sublimate, potassium permanganate, avoid lead or zinc, atropia, cocaine, with perforation, bandage, eserine, excision. For foreign body, antiseptic cotton, spud or curette.

Causes. Corneal wounds are common in working animals by reason of contact with harness, canes, whips, etc., and in the stable from contact with nails or with the hard ends of hay or straw. At pasture the cornea is injured by the ends of long stubble, the sharp points of thistles, the spikes of various thorny plants, and twigs of bushes and trees. The last named factors are especially operative in hunters and horses worked in forests. Punctures with pine needles and cones, and with burdocks, are other common causes. Stones, gravel, pieces of glass, and splinters of wood or metal, produce traumas of the cornea, and, in cats and dogs, scratches and even perforations with the claws are common. In this connection the stings of insects are not to be forgotten.

Symptoms. There is always a prompt and complete closure of the eyelids and a profuse secretion of tears. Then on parting the eyelids with finger and thumb, the lesion of the cornea, its nature and extent should be recognizable. In case of a small, punctured wound, however, as with a smooth thorn or other conical body, the normal elasticity of the corneal tissue may lead to such a perfect coaptation of the divided edges that the lesion may escape even a close scrutiny. If the case is seen early, before time has been allowed for cloudy swelling and opacity the wound is all the more likely to escape observation. In incised, scratched and torn wounds, on the other hand, the seat and nature of the lesion are made out with the greatest ease.

Treatment of a slight wound which is at once recent and free from infection, is by a simple antiseptic bandage and lotion. Boric acid (1 ∶ 100), sublimate solution (1 ∶ 5000) or potassium permanganate solution (1 ∶ 100) may be used. Lead and even zinc salts, are liable to precipitate in the abraded tissue and cause a lasting opacity. If the pain is severe it may be moderated by the addition of atropia sulphate, or a solution of 1 to 100 water may be instilled into the eye several times daily. Cocaine makes an excellent substitute. In deeper wounds, perforating the cornea and allowing the escape of aqueous humor, there may be prolapse of the iris through the wound. It may be pressed back with a flat sterilized spatula, and retained by bandage and a course of eserine. Should it still escape, it must be seized with forceps, drawn out and snipped off with a sharp pair of sterilized scissors. The greatest care must be taken to avoid infection which may cause panophthalmitis and destruction of the entire eyeball.

FOREIGN BODIES IN THE CORNEA.

In case of penetration of the cornea by thorns, thistles, glass, metal, etc., there usually follows inflammation with a red area around the offending object. If the foreign body is a piece of iron there is a brownish area caused by iron oxide. Focal or transillumination will usually reveal the object. Should both fail, a solution of fluorescin when applied will develop a greenish area around it.

Treatment may be made as advised by Gould by pressing a little antiseptic cotton to the front of the eye, so as to entangle and withdraw the foreign body when the eyeball is rolled. Failing in this we may cocainize the eye and remove the offending object with a small curette or spud. A careful focal illumination of the eye will enable the operator to see and remove the smallest particles without injury. Subsequent treatment is that of wounds.

ACUTE KERATITIS. INFLAMMATION OF THE CORNEA.

Extension from conjunctivitis, wounds, foreign bodies, bites, stings, blows, infections, filaria. Symptoms: eye tender, closed, epiphora, red, pannus, photophobia, congested sclera, opaque or ramified red cornea, or diffuse red, exudation, suppuration, corneal abscess, ulcer, perforation, prolapsus iris, panophthalmia. Focal illumination. Recovery. Permanent cicatrix or opacity. Lesions: exudates of lymph and leucocytes into corneal layers: embryonic tissue: vascularization: abscess: ulcer: cicatrix: opacity: staphyloma: hypopion: prolapsus iridis: panophthalmia. Treatment: antiseptic astringents, atropine, leeching, derivatives, blister, seton, opacities; in severe cases antiseptic puncture, sublimate lotion, silver nitrate, potassium permanganate, boric acid, pyoktannin: in perforations antiseptic bandage and eserine, iridectomy: in chronic cases mercury oxide.

Keratitis occurs in all domestic animals as a primary disease, or as an extension from conjunctivitis.

Causes. Extension from acute, enzootic, infectious conjunctivitis in sheep and cattle has been noticed by a great number of observers. Bayer and Lohoff have studied maculated keratitis of the superficial layers in horses. Again it has followed wounds by foreign bodies, spikes of vegetables, particles of iron and glass, blows of whips, or insects, stings, etc. It also occurs in connection with the local action of particular poisons, such as variola (foot and mouth disease), canine distemper, etc., and from the local irritations caused by trichiasis or entropion or by the filariæ lachrymalis (ox) and palpebralis (horse).

Symptoms. The eye is extremely sensitive, and habitually closed, with a profuse flow of tears, and a disposition to resist opening of the lids. When exposed the cornea is seen to be more or less clouded and perhaps reddened by the formation of vessels proceeding from its sclerotic margin. This is known as pannus. If the anterior chamber is still visible the pupil is found to be contracted showing photophobia. The congestion is first visible in the sclerotic and in the absence of pigment is most intense near the margin of the cornea. Upon the cornea itself it is preceded by a deep white opacity, into which the vascularity gradually extends. The whole cornea may finally become of a bright pink hue.

The congestion of the cornea may advance to fibrinous exudation, or the formation of pus between its layers, to molecular degeneration and the formation of ulcer, or even to perforation and escape of the aqueous humor. In this case prolapsus iris, panophthalmia and destruction of the eye are likely to ensue.

Ulcer if not readily seen with unaided vision can be easily recognized by the aid of focal illumination, and abscess can be detected by the presence of a sharply circumscribed centre of intense opacity, white or yellow, and some bulging of the membrane.

The pus may be absorbed, or it may escape by rupture and discharge externally, or into the anterior chamber when the resistance is least in that direction, and when this takes place, a dangerous internal infective inflammation is the result.

In the slighter forms of keratitis the inflammation may come early to a standstill, and recede, tenderness and photophobia pass off, the eyelids may be opened, and the corneal opacities gradually disappear. If any portion of the cornea has become vascular, that portion is liable to remain opaque or even pink.

Lesions. Under the influence of an irritant on the cornea, the vessels in the margin of the sclerotic become actively congested and pour out lymph freely, leucocytes also escape and with the lymph pass through the lymph channels into the substance of the corneal tissue. Here they undergo active fission and increase, and the normal cells of the corneal tissue multiply in like manner, so that in a short time there is an extraordinary production of embryonic cells. Into the embryonic tissue so formed, blood escapes from forming loops of new vessels, and this goes on extending until the whole cornea may have become vascular. Degenerations in the newly formed structure may result in suppuration, (hypopyonkeratitis) or molecular decay and ulceration, (ulcus corneæ) or organization may take place into the fibrous tissue with contraction and permanent opacity, (macula) or a hyperplasia may form in the shape of a staphyloma.

Among the other complications may be named pus in the anterior chamber (hypopion), prolapsus of the iris, iritis and panophthalmia.

Treatment. In the milder form of keratitis, antiseptic astringents with atropia sulphate are often effectual: zinc sulphate, boric acid or alum (1 ∶ 100). Any direct mechanical cause of the irritation must be removed, and the eye rendered as far as possible antiseptic or aseptic. Derivatives also may be of service, and Trasbot especially advises bleeding from the angular vein of the eye but only in the very earliest stages. Cupping, leeching or setons may be employed. Excessive tension may be relieved by puncture of the cornea near its margin. The remaining opacity after the inflammation has subsided may usually be removed by touching it daily with a camel’s hair brush dipped in a solution of silver nitrate (1 ∶ 200).

In the more severe cases antiseptic lotions are even more essential, mercuric chloride (1 ∶ 5000), potassium permanganate (1 ∶ 100), boric acid (1 ∶ 100), silver nitrate (1 ∶ 200). Careful massage is of value.

Ulcers may be touched daily with a solution of silver nitrate (1 ∶ 400), or of pyoktannin (1 ∶ 100).

Perforations must be treated by antiseptic bandage, eserin, and in case of necessity, iridectomy as advised under perforating wounds.

Abscesses of the cornea should be opened with a flamed needle and treated with antiseptic lotions.

Obstinate cases are often benefited by ointment of yellow oxide of mercury 1, vaseline 10, or by the red oxide of mercury or calomel.

POISONING WITH COTTON SEED OR COTTON SEED MEAL.

Poisons in cotton plant: on man, pig, cow, stock cattle. Symptoms in latter: Nervousness, debility, exhaustion, in-cöordination, paresis, dyspnœa, dullness, anorexia, drooping head, trembling, lachrymation, corneal ulcer, opacity, vesiculation; unilateral or bilateral; with rest and change of food recover in five days except eye lesions. Treatment: suspend cotton seed, purge, and treat eye lesions.

The cotton plant develops poisons for various genera of animals. The bark of the root is a favorite abortifacient for woman and may be used for the same purpose in the domestic animals. The seed when fed continuously to swine will destroy life with symptoms of scorbutus, and grave constitutional disorders. Cotton seed meal fed in excess to dairy cows has a bad reputation for inducing garget and mammitis. In stock cattle it has the reputation of producing diarrhœa, running from the eyes, abscess and ulceration of the cornea, staphyloma, hyperthermia (103° to 109° F.), swelled legs, congestion of the liver and spleen, and high colored urine. As described by Dr. F. C. McCurdy, of Kansas City, the southern cattle arrive in poor condition, seem nervous, weak and exhausted, move with an uncertain, staggering gait, and may fall and make convulsive but ineffectual efforts to rise. Dyspnœa, blue mucosæ, and protruded tongue are noticeable in such cases. In the slighter cases, dullness, inappetence, suspended rumination, drooping head, and trembling limbs are characteristic features, and profuse lachrymation is constant. In some eyes there is a small opaque spot around a minute ulcer containing small granules like dust or sand, and situated in the centre of the cornea on the line of approximation of the two eyelids. Larger opaque areas when present were generally confined to the corneal surface, without any areola of distended vessels, and without a vascular zone at the junction of cornea and sclera. In certain cases the whole transparent cornea stood out in the form of a vesicle, so prominently as to interfere with closure of the eyelids. The affection might attack both eyes or only one.

An important feature is that cattle coming from the cars in this condition and left at rest for five days on hay without cotton seed recovered rumination and appetite, and the weakness and nervous excitement or depression disappeared. There remained only the lesions of the eye which progress tardily according to their extent or severity.