Part 70

The southern origin of the cattle, together with the congested liver and spleen and the high colored urine would have suggested the southern cattle fever, but from the promptitude of the recovery under a change of regimen and the prominence of the lesions of the eye.

The important point in connection with this subject is the prophylaxis by avoidance of the too liberal diet of cotton seed. When the disease has actually set in, the true course is to suspend this aliment, clear the bowels of any that may remain therein, and treat the lesions of the eyes according to their respective conditions.

CHRONIC KERATITIS.

Sequel of trichiasis, entropion, eczema, etc. Age. Symptoms: moderate, lids partly closed, cilia matted together, crusted, cornea clouded, dull, with ramifying vessels. Resolution. Fibroid degeneration, permanent opacity. Treatment: tonic regimen, outdoor exercise, iron, bitters, calcium sulphide, astringent antiseptic collyria, atropia, mercury oxide.

This is especially common in dogs in warm latitudes. Trichiasis and entropion are perhaps the most common of the direct causes. Eczema and other skin eruptions affecting the lids are additional causes, while old and debilitated dogs are especially subject to the affection. It is less frequent in horses.

The symptoms are much less severe than in the acute form. The lids are usually partially but rarely completely closed, lachrymation may be absent and is never excessive, the secretion usually sticks together the cilia and lids, and always forms crusts on them, the palpebræ are less sensitive than in acute keratitis, the cornea is habitually clouded of a bluish-white color, yet in the main partially transparent and without the disc opacities of the acute type of disease, and the pupil, which is usually visible in a good light or under oblique illumination, may be slightly but is not excessively contracted. The surface of the cornea seems to have lost some of its polish, and in its substance blood vessels can usually be made out.

Under favorable conditions these cases may end in resolution and especially under a change of food and environment. In less fortunate cases they result in a fibroid degeneration of the cornea and deep permanent opacity.

Treatment. It is usually desirable to change the regimen so as to improve the general health, and to allow a fair amount of outdoor exercise. In the very old and debilitated the case is rather hopeless. A course of iron or bitters will sometimes have a good effect. In other cases sulphide of calcium ⅒ grain thrice a day will prove useful. Eczema must be treated secundum artem.

Locally astringent and antiseptic collyria may be used as in the acute form. Atropia, 5 grs. to the oz., is a valuable adjuvant, to be instilled in drops. Ointment of yellow oxide of mercury, a piece like a pin head rubbed inside the lids once or twice a day often acts well. Finally Trasbot strongly commends liquor of Van Swieten.

OPACITY OF THE CORNEA. NEBULA. MACULA. LEUCOMA.

Nebula, macula, leucoma, pigment spots, infiltration, cicatrix, vascular or not, result of lead, silver or cocaine. Treatment: silver nitrate solution in young and vigorous; calomel: iodoform: avoid mercury and iodine at the same time. Tatooing.

As a sequel of inflammation of the cornea, persistent opacities are very common occurrences. These may last only a short time after the subsidence of the inflammation, or they may be persistent and chronic. They are of all degrees of severity from a mere bluish haze to a dense white cloud, or a dark pigment spot.

The term nebula is given to the slightest form which appears as a grayish blue but still transparent blue and may be so slight as to pass without recognition except under focal or oblique illumination. It shades off gradually into the adjacent healthy cornea, and is often seen as a marginal zone when the centre of the cornea is clear.

=Macula= is more marked, requiring no special illumination to detect it, especially when the dark pupil forms a background for the affected area. It is not, however, of a clear white, but of a grayish blue tint.

=Leucoma= is a dense white spot or patch which reflects all the light falling upon it, and has usually a sharply circumscribed margin.

=Pigment spots= are usually on the membrane of Descemet and are the result of a previous adhesion of the iris and detachment of a portion of its pigment.

The white opacity may be merely a remnant of inflammatory infiltration or it may be a fibrous cicatrix with or without a remaining minute ulcer. It may be the result of an insoluble deposit of lead or silver in the tissues. Sometimes it will form as the result of the application of cocaine.

Treatment. A case of slight inflammatory infiltration can usually be cleared up by touching it daily with a solution of 2 grs. silver nitrate in an ounce of distilled water. This is especially satisfactory in the young and healthy, in which the power of repair is greatest. Finely powdered calomel or iodoform applied to the cornea will often prove effective. In case potassium iodide has been given by the mouth, calomel or corrosive sublimate is liable to form mercurous or mercuric iodide and cause ophthalmia. The same is true of iodoform if mercury has been given internally. As a last resort tatooing the spot has been resorted to, to hide the opacity.

ULCER OF THE CORNEA.

Infection of abrasions may cause ulcer. Age. House dogs. Puppies on vegetable food. Exhaustion. Starvation. Improper, insufficient diet. Specific microbes and toxins. Symptoms: Ulcer with peripheral zone of opacity. Photophobia. In marasmus little other local trouble. Diagnosis by oblique focal illumination or fluorescin. Granulation of Descemete’s membrane. Escape of aqueous. Keratitis. Panophthalmia. Staphyloma. Prognosis in debilitated, vigorous. Treatment: tonics, fresh air, good food, sunshine, exercise, silver nitrate, mercuric chloride, iodoform, alcohol, chlorine water, boric acid, cocaine, eserine, atropine, warm antiseptic compress, juice of fresh cassava.

Causes. Wounds of the cornea making an infection entrance for pus microbes, are liable to lead to ulceration, and a corresponding destruction of the epithelium and superficial layers by inflammation, may start a similar ulcerative process. Apart from these conditions, ulceration is especially liable to occur in very old dogs, in closely confined house dogs, in puppies raised on an exclusive diet of vegetable food, and in animals worn out by disease, exhaustion, starvation, or improper and insufficient diet. Majendie’s dogs fed on sugar, starch and other imperfect diet, suffered in this way. Finally, the local action of certain specific disease poisons, enzootic purulent ophthalmia, canine distemper, dogpox (Trasbot), equine influenza (Schindelka), sheep pox, and blennorrhœa (Möller), leads to ulceration.

Symptoms. In keratitis there is usually a marked local opacity in the centre of which the breach of the surface may be found. The attendant photophobia with closure of the lids and pupil is strongly suggestive of ulcer. In the specific diseases, the local inflammation, the rapid progress of the lesion and the coexistence of the particular infective disease are characteristic. In cases due to debility and marasmus the disease may appear with little indication of attendant irritation, lachrymation, tenderness, photophobia, or even opacity. At one circumscribed point only is there a grayish cloud, perhaps no more than a thirtieth of an inch in diameter, and slightly projecting. This becomes soft and gelatinous and finally drops off, leaving a shallow excavation or abrasion, surrounded by a narrow grayish zone. This necrobiosis may extend inward and even penetrate the membrane, before the lesion has enlarged to more than a hemp seed in diameter. In other cases lateral extension occurs.

It is always important to recognize the ulcer at an early stage, and this may be done by oblique focal illumination and the use of a magnifying lens. In case of doubt a drop of solution of fluorescin placed on the cornea and at once washed out, will promptly reveal the lesion by the high color given to the tissues which have been denuded.

When perforation has taken place the membrane of Descemet may bulge out of the orifice and undergo granulation, or it may open and allow the escape of the aqueous humor. Active keratitis and even panophthalmia are liable to follow perforation. Again, the escape of aqueous humor tends to the approximation or contact of the iris with the cornea, where it may become adherent and staphyloma may ensue.

Prognosis is unfavorable in debilitated subjects, and when the lesion is extensive and in the line of vision. In slight recent cases in good constitutions it is favorable.

Treatment. Debility must be met by tonics and rich diet, fresh air, sunshine and exercise. Specific diseases must be met according to their nature.

Locally the daily application of silver nitrate lotion (1 ∶ 200) is often very effective, proving an excellent antiseptic, checking the microbian proliferation, and coagulating the albumen in the wound so as to form an antiseptic barrier to further invasion. A mercuric chloride solution (1 ∶ 5000) is an excellent substitute. Iodoform powder though less antiseptic, is especially valuable in favoring the healing process. It is dusted over the cornea, and the upper lid immediately drawn down and held over the cornea for several minutes. If this is neglected the dry powder is removed by the flow of tears, and the movement of the lids and membrana nictitans. Trasbot recommends dilute alcohol (5 ∶ 100). Möller advises chlorine water reduced to one-third the standard strength, or boric acid solution (2 ∶ 100). Bouley found good results from a cocaine solution. Cadiot and Almy get the best results from creolin (.5 to 1 ∶ 1000) 5 or 6 times a day, with eserine.

In all cases great relief can be obtained from a strong atropia lotion (1 ∶ 100). Indolent cases may often be helped by warm antiseptic compresses, which seem to stimulate the circulation and nutrition of the part. The juice exuding from the scraped fresh cassava and concentrated to a syrupy consistency, is strongly antiseptic, and used with atropia or pilocarpin is the best agent known for senile ulcer (Risley).