Definition. Causes: wet impermeable soil, clay, river bottoms, deep
valleys, inundations, enclosing forests, damp air, lack of sunshine,
rank fodders, wet seasons, damp, cold, basement stables, heating
constipating fodder (corn, buckwheat, wheat), dentition, training, age
of domestication, sale, etc., spring, shedding coat, heredity,
debility, ill health, worms, debilitating infectious diseases, over
work, insufficient, indigestible food, local irritants. Microbes.
Rheumatism. Parasitism. Symptoms: fever variable, lack of vigor,
sudden attack, irritation, photophobia, lachrymation, closed lids,
contracted pupils, retracted eye, redness, swelling of lids,
conjunctiva, haw, sclera, slight corneal opacity, with vascularity,
aqueous turbid, flocculent, iris of dull color, sluggish, pupil
contracted, hypopion, posterior chamber yellowish green, intraocular
tension, crisis seventh to tenth day, convalescence fifteenth day.
Recurrence. Obscurity of vision. Eye between attack: blue zone around
cornea, eye seems smaller, retracted, prominent haw, angle in upper
lid, dull iris, tint lighter, contracted pupil, cataract, alert ears.
Lesions: exudates back of cornea, narrowed anterior chamber, sizy
aqueous, thickened iris, adhesions of lens capsule, or iris, torn
iris, lens opaque, fibroid, calcareous, atrophied, black cataract,
vitreous opaque, yellow, black, shrunken, choroid uneven, discolored,
detached, retina with exudate, detached, posterior chamber contracted.
Prevention: drainage, mature horses for damp lands, liming soil, get
fodder from dry locality, don’t breed in cloudy regions, good diet and
regimen, avoid corn, wheat and buckwheat, Glauber salts, pure dry
stable, exclude debilitating diseases and parasites, keep in hard
muscular condition, change to dry locality, don’t breed from blind
stock, legislation. Treatment: remove causes, cure rheumatism or other
morbid factor, darkness, antiphlogistics, laxative, diuretic, local
bleeding, cupping, blister, seton, locally atropine, cocaine,
pyoktannin, sublimate, lead, puncture, tonics, treat corneal
opacities. Jurisprudence: return a newly bought horse in 30 days,
(France) or more: extend the time if suspected.
_Definition._ This is an inflammatory affection of the interior of the
eye, intimately related to certain constitutions, soils, climates, and
systems of management, showing a strong tendency to recur again and
again, and usually ending in blindness from cataract or other
destructive lesion.
_Causes._ A =wet, impermeable, swampy or undrained soil= is a potent
cause of this disease. Heavy clays, which absorb and retain moisture,
river bottoms and deltas which are frequently overflowed and constantly
wet, hollow basins where no effective drainage has been secured, and the
coasts of seas and lakes which scarcely rise above the level of the
water and are submerged at intervals, are the especial homes of the
affection. In time past the disease was very prevalent in the low
districts of France (Reynal), Belgium, Alsace-Loraine (Zundel,
Miltenberger,) Germany, Holland (Möller), the English fen country and
above all the damp lands of Ireland. Lafosse mentions a whole family of
horses in South Western France which were characterized by blindness.
Reynal records the terrible devastation which it caused in former times
in the government studs at Limousin and Pompadour. It also prevails on
the low banks of the Guadalquivir near Seville (Hurtrel d’Arboval),
around Ostend, Cassel and Frankfort (Hofgeismar). Wet soils surrounded
by forests or hills, which hinder free circulation of air, are
especially injurious (Reynal). At Schlestadt, Alsace, at the beginning
of this century, Miltenberger found 75 per cent. of the horses of the
environs affected, whereas after great drainage works and the removal of
all stagnant water Zundel found in 1870 not more than 2 per cent. In
many localities in England, Ireland, France, Belgium and Germany the
disease has greatly diminished in connection with land drainage and
improved methods of culture. Harmon tells how in different parts of
Brittany, drainage supplemented by the free use of marl and lime on the
soil has caused a striking decrease in the prevalence of the malady. In
the department of Ain a ratio of 333 per 1000 was thus reduced to 100
per 1000 (Reynal). On the contrary in the absence of such drying of the
soil the previous high ratio of attacks was maintained. This has been
notorious in the damp lands of Northern France and Belgium (Picardy,
Artois, Flanders, where it often reaches 40 to 70 per cent. Reynal):
Alsace-Loraine, Holland, Hanover, Mecklenberg, North and East Prussia,
Lithuania, the low parts of Austria and Hungary and the Danubian
Principalities—Moldavia and Walachia.
Reynal further shows that dealers are in the habit of taking young
horses, which have so far escaped, or which have suffered but one
moderate attack, away from the low damp soils of the low Pyrenees or of
the Jura Valley in France to the dry elevated lands of Dauphiny,
Provence and Languedoc in France, or to the mountainous regions of
Catalonia in Spain in the well justified confidence that few of them
will suffer a second attack.
As a direct test the French Government sent ten yearling foals from the
affected depot at Limousin to the healthy depot at Tarbes, retaining an
equal number at home as test animals: it also sent ten yearlings from
Tarbes to Limousin, retaining an equal number at Tarbes as test cases.
Then the twenty yearlings at Limousin were divided, five of the home
bred and five drawn from Tarbes having been sent into a very low wet
country at Lariviere, and the rest were sent to a high dry location at
Maraval. The result was that but one of the ten yearlings sent from
Limousin to Tarbes contracted the disease, while on the damp land at
Lariviere one Limousin-bred and four Tarbes-bred colts suffered; and
finally on the dry soil at Maraval not a single colt, from either
Limousin or Tarbes was attacked.
The other conditions that usually attach to a low, damp soil are
important factors. =Damp air and a cloudy, rainy climate= are potent
accessory causes. Hence the great prevalence of the disease formerly in
Ireland, on the west coast and in the fen country in England, in
Belgium, in the Low Pyrenees, in the valleys of the Loire, Jura, Meuse,
Moselle, the Guadalquivir, etc., (Reynal). Such an atmosphere relaxes
the system, induces a heavy lymphatic temperament, with coarse bones and
muscles, an excess of connective tissue, thick hide and hair, and thick,
shaggy and often gummy legs. All this implies a low tone of health which
will less effectually withstand inimical influences.
The =rank, aqueous fodders= grown on such damp localities have a similar
effect. These are more bulky and less nutritive and fail to maintain the
highest tone and vigor. The animals must overload the stomach and
intestines in order to obtain the requisite amount of nutriment, so that
with a large, pendent belly they are still in poor condition. The case
is even aggravated when they go on the succulent grasses of early
spring, as they continue to gorge and may even make fat, but they lack
in muscle and tone and in this condition even the rapid formation of
blood seems to favor the attack. Möller records the great prevalence of
the disease in Central Germany in 1884, in connection with excessive
rainfall, inundations, and spoiled fodder.
Dard records that a low, overflowed meadow in the Soane bottom near
Chalons, caused blindness in nearly all horses put upon it. Bouin quotes
a case of a sewage irrigated meadow in Vendée which almost infallibly
produced recurrent ophthalmia in the horses fed on its products. On the
other hand, oats and hay from a dry, rich soil and well harvested, are
the most trustworthy food when the disease is to be dreaded.
=Damp night air on wet, impermeable soils= is to be especially feared as
not only relaxing the system and lowering its power of resistance, but
also producing a chill and thereby increasing the susceptibility.
=Damp, cold basement stables= are concurrent causes acting like the wet
soils, the damp air, and the attendant relaxing conditions. Thierry long
ago noticed that improved stable hygiene around Strassburg led to a
notable decrease of recurrent ophthalmia. In 1807 horses were blind to
the extent of 16.5 per cent., in 1821 to 8.5 per cent., and in 1870
Zundel found but 1.79 per cent., and few of the latter from recurrent
ophthalmia.
Again the ventilation, lighting and drying of close, low, dark damp
stables where the disease had previously prevailed has often practically
banished the affection. Hofgeismar states that during the prevalence of
the disease in a detachment of the German army in Alsace, out of 84
attacks in 700 horses 52 appeared in February and March, the period of
severe weather and close stabling.
=Fodders of a heating, or starchy nature=, like =Indian corn=,
=buckwheat=, or =wheat= strongly predispose to the disease, probably by
inducing costiveness, slight impactions and indigestions, and in bad,
frequently recurring cases the writer rarely fails to find that the
animal is being fed on corn. Beans, peas, vetches and other leguminous
fodders are less injurious and when grown on high, dry soils and fed
judiciously they are as a rule harmless. When grown rank, badly
harvested, and used to excess they become distinctly hurtful. Any fodder
which has been allowed to become musty is to be avoided, since any
condition which lowers the general tone of health strongly predisposes
to an attack. The same remark applies to irregularities and faults in
feeding. The best food and the most abundant supply will fail under such
circumstances to maintain the condition, and the horse that is losing
condition is becoming increasingly susceptible to this malady.
The period of =dentition= and =training= is the most common occasion for
the attack, partly because this is the time when the colt is taken from
the pure air and exercise of the field, into the hot, close, impure
atmosphere of the stable, partly because he is made to exchange the
cooling succulent grass for the stimulating ration of hay and grain,
partly because he is subjected to severe constraint and much excitement
in the hands of the trainer, and partly because of the irritation of the
gums, the jaws and the whole head in connection with the shedding and
eruption of the teeth. When injudicious biting is resorted to, to give a
special curve to the neck, the consequent obstruction of the jugulars
and capillary congestion in the head is another potent cause. Heavy
draught and overdriving have a similar effect. In 53 cases Schmidt found
that 3 occurred under one year old, 5 in the 2d year, 10 in the 3d year,
16 in the 4th, 15 in the 5th, and 4 from the 5th to the 9th years.
=Influence of Season.= Mayer gives a statement of the percentages seen
in the various months of the year as follows: January 4.9%, February
4.7%, March 10.1%, April 15.1%, May 13.4%, June 9.9%, July 11.9%, August
6.4%, September 4.9%, October 6.2%, November 6.7%, December 5.2%. The
high rate in March, April and May may have a significance in connection
with the debility connected with shedding the coat, and the resumption
of more active work, when somewhat out of condition, it must also be
noted that this is in Germany the season of the most active trade in
horses and consequent change of ownership, stabling, feeding, work and
management.
=Heredity= must be accepted as one of the most potent accessory causes.
The lymphatic constitution is of course transmitted and with it the
special susceptibility. This is notorious in the case of both parents,
and is of course more potent if both sire and dam were predisposed, and
have themselves suffered. In the latter case the heredity of the
lymphatic temperament, and of the impaired organ of vision combine to
render transmission more certain. A mare may have borne a number of
sound foals before suffering from the malady and then have offspring
that do contract the disease. So with the stallion. Möller quotes the
case of the eastern horse Turk-Mayn-Atty which served for a length of
time in Prussian Studs and left a great stock of blind progeny. Lafosse
records the existence of a family of horses in Southern France all of
which went blind. The same cause has greatly extended the disease among
fast American horses in which the great strain of the track served to
intensify the tendency. The writer has seen a colt which was born blind,
by a blind dam and got by a sire with diseased eyes, but still held at
$300 for service. Mangin, Marimpocy and Hamon record congenital cases
from parents with affected eyes.
This hereditary susceptibility is so strong and pernicious that
intelligent horsemen everywhere refuse to breed from either horse or
mare that has once suffered from recurrent ophthalmia, and at the
Government studs in France not only is every unsound stallion rejected
but the service of the healthy stallion is refused to any mare which has
suffered from disease of the eyes. A consideration for the future of our
horses would demand that no stallion shall stand for the public service
of mares unless he has been examined and licensed as a sound animal.
Yet, as already stated, heredity is not the one controlling factor,
since the offspring of the victims of this disease will often escape
when brought up in a high, dry locality.
Reynal records the appearance of the disease in =alternate generations=,
the stallion offspring of blind parents remaining sound himself but
producing foals which became victims of the disease in large numbers. A
partial explanation may be found in the better conditions under which
the stud horse was kept, while under less favorable surroundings his
offspring developed the disease.
It must be added that every condition which induces =debility= or =ill
health= is favorable to the development of the malady. The presence of
=worms in the bowels= is a familiar example. Any debilitating disease
like =strangles=, =influenza=, =contagious pneumonia=, =indigestion=,
etc., and overwork or insufficient or indigestible food act in the same
manner.
Again, =local irritants= may rouse the latent tendency. Street or stable
dust, sand, hay seeds, chaff, blows on the eye with whip or other
object, wounds, irritant gases, smoke, fierce light, cold draughts,
storms, and whatever determines inflammation of the eye may be the
occasion of an outbreak of recurrent ophthalmia.
=Microbiology.= It will be recognized that none of these causes fully
account for the specific and recurrent nature of this affection, and it
is felt that something more is wanted to furnish a full and satisfactory
explanation of the malady. This explanation is sought in a direct
_infection_, but in spite of extended investigations by many observers
no specific microbe has been demonstrated as uniformly present in all
cases.
Potapenke found in the blood of the affected horses a plasmodium like
that of ague. This agrees with the damp regions in which the malady
prevails and no less with its intermittent or periodic character.
Vigezzi found in the aqueous and tissues a micrococcus
(ophthalmo-coccus) which, cultivated on gelatin agar and inoculated in
the anterior chamber or under the conjunctiva, produced an affection
which he recognized as recurrent ophthalmia.
Trinchera found in the aqueous of the affected animals a bacillus and
cocci. Drawing this aqueous into a sterilized syringe and injecting it
into the anterior chamber of sound horses produced in 12 to 48 hours
characteristic periodic ophthalmia. This was repeated by Schütz and
Schwartznecker.
Robert Koch found in the affected aqueous, cocci, singly or in chains
and bacilli with rounded ends. Injection of the latter into a sound
horse’s eye led to characteristic inflammation and loss of vision. In
the cornea of the rabbit it had no effect.
Richter found in the eyes of a foal born with recurrent ophthalmia, of
sound parents, diplococci and triplococci.
These observations do not demonstrate the constant presence of one
definite microbe, nor that the disease is invariably due to any one
particular organism, yet they may be held as strongly suggestive that
any one of a variety of microörganisms may prove an exciting etiological
factor in a susceptible system, or that, along with the organisms
heretofore demonstrated, there exists an essential microbian cause which
has up to the present eluded detection.
Other points which give circumstantial support to the microbian theory
may be shortly stated:
1. The recrudescence of the disease after its various intermissions, and
its preference for low, damp, cloudy localities seem to ally it to the
malarial diseases of man.
2. Its appearance in certain predisposed systems, whenever an injury or
debility of the eye seems to open the way for the admission of the
hypothetical microbe.
3. The increased susceptibility to the malady when the system has been
debilitated by disease, overwork, heating food, bad hygiene, or
parasitisms, which have undermined the native power of resistance.
4. The prevalence of the affection in given localities has been supposed
to imply the preservation and perhaps the multiplication of the germ in
such places.
5. The increasing number of victims, year by year, when the same
regiment or stud has been kept for a number of years in the same place.
The theory is that with the presence of infected horses the hypothetical
microbes become increasingly prevalent in the locality and above all in
the stables, until even the more resistent subjects tend to succumb
under the repeated infections. Thus Zundel says that in 1878, 700 army
horses were stationed in Saarsburg, in 1879, 6 were attacked with
recurrent ophthalmia, and in 1880, 84, Hofgeismar mentions that a
dragoon regiment in Frankfort had 5 horses attacked in 1876, 12 in 1877,
11 in 1878, 14 in 1879, and 42 in 1880. We have, however, no assurance
that the excessive rainfall, spoiled food or other unhygienic condition,
may not have been a potent factor in the increase.
6. The obvious connection of certain cases of recurrent ophthalmia with
a rheumatic condition suggests the probable operation of the same
microbian cause.
Up to the present the microbian causation of this malady cannot be taken
as proved, yet as a hypothesis it explains satisfactorily many of the
observed morbid phenomena. That there is no such rapidly spreading
infection, as would warrant us in listing this with animal plagues, is
conceded, and that constitutional conditions have a potent influence is
allowed, but that, in addition to these, microbian invasion is often a
means of precipitating the malady is altogether probable. It may not be
necessary that the microbe should in every case be of the same kind, yet
the addition of a germ as the last item in the chain of causes is
presumptively true.
=Parasitism.= Willach claims that many cases are directly due to
parasites in the eye. In 19 affected eyes he found one young filaria, a
number of rhabditis (?), 1 cysticercus, and a number of distomata.
Leider also found round worms in such eyes. Mayer and Dexler examined a
number of cases, using the centrifuge on the liquids of the eye, without
in any case finding such parasites. It may be assumed that the presence
of embryo worms may rouse a latent predisposition into activity, but
they cannot be adduced as active causes in the vast majority of cases.
_Symptoms._ These vary with the severity of the attack. In some cases
there is high fever while in others this may be absent, yet a lack of
vigor and energy bespeaks a general constitutional disturbance. The
attack is sudden with marked local irritation, photophobia and
lachrymation. The eyelids are closed some times so firmly as to suggest
blepharospasm, and if opened the pupil is seen to be contracted. The
affected eye is retracted and appears smaller, the conjunctiva is the
seat of diffuse redness and swelling, and there is a bright red
peri-corneal injection, occupying the anterior portion of the sclera.
The outer zone of the cornea is already the seat of a bluish white
opacity, the surface appearing dull and as it were smeared with oil. The
centre of the cornea may be opalescent but not so obscure as to prevent
examination of the interior of the eye. In a few days the outer margin
of the cornea may show vascularity, and the aqueous humor a certain
degree of turbidity. The iris if still visible is seen to be swollen and
rigid, and to have parted with some of its lustre, assuming a grayish or
lighter color owing to congestion and exudation. The pupil is usually
contracted and dilates only sluggishly and imperfectly in darkness or
under the action of atropia. The iris arches forward more than is normal
and may even approximate and adhere to the back of the cornea. Bayer
noticed that in a partial albino (watch eye) the iris becomes sulphur
yellow. The anterior chamber of the aqueous humor usually shows a
grayish yellow sediment which in severe cases may fill one-third or even
one-half of its depth. This may be grayish white flocculi of lymph only,
or it may be colored with blood or in suppurative cases by pus. In the
first day of its appearance this may be diffused through the humor, but
from the fifth to the seventh day it precipitates and leaves the iris
and pupil open to inspection. The pupil if not already open, may be
partially dilated with atropia and then discloses the interior of the
eye of a dark green, or sometimes with much exudate on the choroid, of a
more yellowish green. This greenish discoloration appears to depend on
opacity of the vitreous, on an exudate between the choroid and retina or
on some opacity of the cornea and aqueous. At the same time under a good
light some opacity of the lens or its capsule may be detected, or, with
direct illumination, of the vitreous as well.
The tension and hardness of the bulb is materially increased in some
cases but not at all perceptibly in others.
From the seventh to the tenth day the acute inflammation subsides, the
lids and pupils dilate, and the deposit in the anterior chamber is
rapidly reabsorbed. It may first assume a dull brownish green or
brownish tint. Meanwhile the opacity of the cornea commences to clear
up, and any redness or congestion of its margin to diminish or
disappear.
With this disappearance of opacities in the cornea, lens and humors, all
the symptoms of congestion subside and by the tenth or fifteenth day
from the commencement of the attack the eye may have become approximated
to its normal condition.
The characteristic of the disease, however, is its tendency to return
again and again until the eye is destroyed. From five to seven attacks
usually result in blindness, and then the second eye is likely to have a
similar experience until both are useless. In some instances the eye
which is first attacked may recover and remain well, while the second to
suffer is rapidly ruined by a succession of severe attacks. The
intervals between the attacks may be thirty, forty or sixty days and
upward according to the state of the health, the condition, the food,
the regimen, the exposure, and perhaps of other accessory causes.
Reynal claims that some eyes which have retained their normal function
after one or two attacks will sometimes gradually lose the power of
vision without any new appearance of inflammation. In other cases an eye
which has been clear and transparent becomes suddenly filled up with an
inflammatory exudation in the anterior chamber which obscures the iris
and lens and in a few days vision is permanently lost, yet without
conjunctivitis or apparent suffering.
=Condition of the eye between attacks.= After one, two or more attacks
the eye is not restored to its former condition in the intervals, but
continues to exhibit morbid phenomena which betray the previous
existence of the disease. The recognition of such persisting lesions is
all the more easy that one eye only is usually attacked at first and a
comparison between this and the sound eye renders the modifications all
the more patent. Even after a first attack there is usually a hazy
bluish white zone round the outer margin of the cornea and this becomes
more distinct after each successive attack. The faulty eye is distinctly
smaller in appearance, at first because it is retracted in its sheath
and later in certain cases because of actual atrophy. In proportion to
the retraction of the bulb, is the protrusion of the membrana nictitans
which covers a greater part of that eye than of its fellow. The upper
eyelid in place of forming a continuous and regular arch shows a
distinct abrupt bend between its inner and middle thirds caused by the
contraction of the levator muscle. The front of the iris has lost
something of its normal lustre, and the posterior chamber is liable to
show an abnormally light reflection, greenish yellow or yellowish blue.
Under direct illumination, lines of opacity may be detected in the
aqueous humor, or in the lens, or dark filaments in the vitreous. After
several attacks the lens is very distinctly obscure and this increases
with each relapse to a white or yellowish white complete opacity. After
the first or second attack the pupil may be distinctly contracted, while
later in the disease, with advanced cataract it is usually widely
dilated. Another feature is the erect, attentive carriage of the ear, to
compensate for the waning vision.
_Lesions._ These are not often seen, as animals do not often die of this
disease. Beside the superficial lesions of the conjunctiva and cornea
which may be seen during life, exudates have been found on the posterior
surface of the cornea, in some cases binding that to the iris. In
advanced cases the greatly contracted anterior chamber may contain a
little mucilaginous liquid strongly pigmented with debris from the iris,
the whole mixed with shreds of exudation. The iris is thickened by
congestion and by exudation on its surface and in its substance, and is
displaced forward so as to diminish the size of the anterior chamber,
and it may have contracted adhesions with the cornea (anterior synechia)
or with the lens (posterior synechia). This leads to unevenness in the
pupillary margin, where the iris is often torn into shreds. The
crystalline lens is usually opaque, and may have undergone various
changes, fibrous, calcareous, or atrophic. The anterior surface of its
capsule has often adherent masses of black pigment derived from the urea
in previous adhesions.
The vitreous humor and hyaloid membrane are sometimes clear, but usually
yellowish or blackish and reduced to one-half their normal bulk by
accumulations under the retina. A dense exudate often exists on the
lamina cribrosa. The choroid is very uneven showing irregular rounded
elevations, and like the iris is the seat of active congestion,
exudation and thickening. The exudate on its surface raises and detaches
the retina and, as shown by Eversbusch, this may increase so that the
retina from the two sides may come together in the centre of the eye,
the vitreous having been absorbed and removed. Reynal records instances
in which the exudate had become cretified, or as he claimed transformed
into true bony tissue. Finally the optic nerve is atrophied, often in
advanced cases to half its natural thickness.
_Prevention._ As treatment is somewhat unsatisfactory there is the
greater reason to give attention to measures of prevention.
In view of the great evil of low, damp, overflowed lands, it is
important to drain and improve such lands whenever possible, and when
this cannot be done, to abandon the breeding of horses upon them, and to
buy the animals necessary for agricultural purposes from high, dry,
healthy localities and introduce them only after they have passed the
age of five years at least.
The improvement of wet lands by liming, so as to lessen the amount of
decomposing organic matter, and improve the character of the vegetation
has proved very beneficial in different parts of England. The
substitution for the products of marshy meadows and wet lands, of those
of dry cultivated meadows and lands is important.
Misty cloudy regions in the vicinity of sheets of water, or cold
mountain ranges cannot be made wholesome, but they can be abandoned for
horse breeding, and devoted to more remunerative uses. Something may
also be done by stabling the working horses at night.
An insufficient or debilitating diet, for example, in winter, should be
carefully avoided, the more so if it is to be followed by a sudden
access to rich grass in the spring.
All forms of spoiled food, damp, musty, or fermented fodders should be
withheld, especially in the case of young and growing horses.
Indian corn, wheat and buckwheat should be carefully excluded from the
grain ration or if used should be combined with 1 oz. sulphate of soda
for each animal daily.
Damp, close, filthy and underground (basement) stables should be
avoided, the building on the other hand should be placed on high, porous
and well drained ground, and should be clean, moderately well lighted
and well ventilated but without draughts. While such special stable
hygiene is demanded for all it is doubly demanded for young horses under
six years of age.
As every debilitating condition renders the already predisposed animal
more open to attack, all causes of ill health should be guarded against,
and especially for the young, and in the case of such as are inevitable,
every effort should be made to curtail and lessen the evil influence.
Food or water which contains the eggs and embryos of intestinal worms,
must be avoided and parasites which have already invaded the system must
be got rid of as far as possible. Care must be taken to exclude the
various infectious diseases, and in case of their introduction, to adopt
every measure to mitigate their violence and to prevent debility and
weakness. Overwork and irregular feeding and watering must be guarded
against.
At the same time moderate work or exercise daily which will develop the
highest tone of the muscles, nervous system, digestion, assimilation and
other functions is a measure that can never be neglected. Idleness with
resulting fatness, softness and weakness of muscle, and lowering of the
power of endurance is always an invitation to renewed attacks. Regular
invigorating work is essential; exhausting work is injurious.
Change of locality to a drier soil, clearer, drier atmosphere, and more
abundant sunshine, when it can be availed of, is a most important
preventive measure. Reynal who made an extended official inquiry into
this matter found conclusive evidence of its truth. Young horses removed
from the low affected regions of Cantal, Poitou, Brittany and Anjou
rarely suffered another attack when taken to the high land of Catalonia,
and those moved from the damp lands of Franche Compté, Bresse, Dauphiny,
Provence, Languedoc, Bassigny and Belgium to the dry, calcareous
portions of Champaigne also escaped further trouble. In many such cases
the eyes already slightly affected would materially and permanently
improve.
Finally the influence of heredity is never to be over looked. The ideal
system would be to have all stallions professionally examined, and
licenses granted to such only as are free from this affection, and to
place the owners of such horses under obligation to serve only, mares
the eyes of which are sound. This might be enforced as a state or county
ordinance. Serious difficulties it is true stand in the way of such a
measure. The horse which has an extraordinary record on the track, and
to the development of the ophthalmia of which, overwork has doubtless
contributed, will be run after by breeders who seek speed at any cost,
and it may be questioned whether the State has any right to interfere
with the prospective profit which may be expected from the reproduction
of the strain of blood. But aside from such fancy products as racers and
trotters, this objection has much less force. For carriage, riding and
road horses and for the draught and agricultural animal the advantage of
sound eyes so greatly over balances all consideration of special values
with imperfect eyes, that a statute which will prevent the propagation
of such unsoundness is more than justified in every case. The importance
of this will be admitted when it is considered that in the great
majority of cases, the young animal is attacked after it leaves the
hands of the breeder, and therefore a high price is secured for a
subject which is almost certainly doomed to become blind in given
surroundings. Such a law would work well in every locality. In the low,
damp region where the disease prevails habitually, the unprofitable
breeding would practically cease, unless a race could be secured which
was proof against the infection. The value of such a race could hardly
be over-estimated. On the high, dry lands, on the other hand, the
natural tendency to immunity would be still further enhanced, as the
most susceptible animals which contracted the disease, in even such a
healthful district, could be in no sense fit for reproduction, and
should therefore be doubly condemned.
In the case of the mare the proprietor is under strong temptation to
ignore the sanitary measure under consideration. When her eyes fail, her
value in the public market is greatly depreciated, yet she can yearly
produce a foal, which is finely developed and will bring a high price if
sold young, before it has been attacked by the disease. Hence the great
importance, at least in the case of all horses which are not intended
for exclusive use on the race course, that a law shall be strictly
enforced which will put an absolute limit to the breeding from horses
that have been affected with recurrent ophthalmia.
Blows, dust, sand, smoke, irritant gases, fierce light, and all sources
of irritation must be avoided as in other eye diseases.
_Treatment._ Radical treatment for the disease is far from generally
satisfactory. Too often the affected animal is still in the environment
which has tended strongly to its development, and it is impossible to
secure a satisfactory change. As far as possible, however, every
available sanitary measure mentioned under the head of prevention should
be enjoined, and largely in proportion to the thoroughness of such
measures, and the slightness and recentness of the attack will be the
hope of a successful treatment.
In some instances in which there appears to be a rheumatic complication,
the employment of anti-rheumatic agents have proved of essential value.
Powdered colchicum corms may be given twice a day in doses of 1 scruple,
combined with salicylate of soda, salicylic acid, or salicin in 2 drachm
doses. To these may be added bicarbonate of soda or of potash in drachm
doses.
In cases attended with marked fever, hyperthermia and anorexia,
antiphlogistic treatment may be desirable, but with the primary
consideration that it must not be materially depleting, nor calculated
to induce debility or atony. A laxative dose of aloes will sometimes
benefit, but should be avoided in the absence of manifest fever. Two or
three ounces of Glauber salts, twice a day, will effect the same purpose
with less danger. Or saltpeter or other cooling diuretic may be given
daily. In most cases bitters may be added with advantage.
In severe cases, rest is essential until the violence of the
inflammation shall have abated, and a dark stall or a cloth to obscure
the light is equally important.
Trasbot advises bleeding from the jugular, but such a depleting measure
finds little support in England or America. =Local bleeding= from the
angular vein of the eye or by leeching or cupping is not open to the
same objection.
=Counter-irritants= are, however, more suitable. A stout silk thread may
be inserted above the lower end of the zygomatic ridge and bathed and
moved daily to prevent the lodgment of pus. Or a blister of cantharides
or biniodide of mercury may be rubbed in on an area as large as a silver
dollar in the same situation.
In all cases a strong solution of =atropia sulphate= (2 per cent.) may
be instilled into the eye once or twice daily. Or a mixture of atropia
and cocaine (1 per cent. of each) will give even greater relief. If to
these is added 1 per cent. of pyoktannin we get a collyrium which is at
once anæsthetic, midriatic and antiseptic. This is often of material
value. Vigezzi advises a mercuric chloride lotion (1 ∶ 1000) as a
collyrium, and for injection in the submucosa.
If the local inflammation runs high an astringent lotion may be applied
externally on a soft rag hung over the eye and kept constantly wet.
Sugar of lead or acetate of zinc may form the basis of such lotion with
a little atropia or morphia added.
=Puncture of the cornea= and =iridectomy= have been strongly advocated
on the ground that the disease is identical with glaucoma, but the
burden of evidence is decidedly against their use as a regular method of
treatment. In case of increased intraocular tension, however, the
puncture of the cornea can be very profitably employed, but it should be
reserved for such special cases. Theoretically, iridectomy should be
advantageous in preventing a relapse, but experience has not fully
sustained this. When employed, the most careful disinfection should be
secured. Under rational treatment the attack subsides in ten days and
the eye may appear to be restored to the normal condition in two weeks.
This natural tendency to a temporary recovery has served to give a wide
acceptance to the most irrational methods of treatment, which have not
in any sense hastened the recovery.
As soon as active inflammation and hyperthermia subside, every attention
should be given to prevent a relapse, and to this end all the measures
mentioned under prevention and which can be applied to the individual
case should be adopted. Among these, moderate exercise or regular work
must never be omitted.
A course of tonics embracing preparations of iron and bitters, is
equally essential, and may be begun as soon as fever and active
inflammation subside.
Special lesions, like corneal opacities and ulcers, must be treated as
in other affections.
=Jurisprudence.= The question of the right to return upon the seller a
horse attacked with recurrent ophthalmia has been beset with difficulty,
mainly because of the intermissions during which, to the ordinary
observer, the eyes may appear sound. In France a period of thirty days
is allowed in which to return such a horse after purchase. This is,
however, too narrow a margin as the second attack may not appear until
after two, four or six months. It does, however, provide for the return
of the worst cases in which the recurrence is likely to take place at an
early date. Another provision is that a suspected horse may be put in
pound under veterinary observation for thirty days, in anticipation of a
second attack, and if such fails to appear the purchaser is debarred
from returning him.
In many cases the symptoms during an attack and between attacks are such
as to identify the recurrent inflammation, and the expert can pronounce
positively as to the nature of the malady. In other cases there is a
degree of uncertainty, and the animal must either be returned on the
general plea of diseased eyes, if they can be shown to have been faulty
at the time of sale, or otherwise the horse must be put in the hands of
a veterinarian and the seller notified of the action, until it can be
shown whether it is the recurrent disease or not. If it can be shown
that the disease is the recurrent affection the seller is responsible at
common law for selling a diseased animal for a sound one. If on the
other hand, it is a non-specific ophthalmia, it must be shown that it
existed prior to sale, and that a warranty of soundness was given, in
order to hold the seller responsible.