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).
In perforation use eserine, and antiseptic bandages and in case of
prolapsus iris, excise as already advised.