Chapter XIV: Part 14

4th. =Determine the vascularity of the conjunctiva.= When free from pigment as it habitually is in pigs and birds this is easily done, while in animals like the horse, in which the bulbar portion, which covers the sclerotic, is largely pigmented, we can scrutinize only the pigment free parts. =In health= there should be only a few, fine, pink vessels which move with the mucosa when pressed aside on the bulb. =In congestion= the surface may appear brick red, and the vessels are irregular, large, tortuous and are seen to anastomose at frequent intervals. These move on the bulb when pressed. The congestion is usually deepest on the palpebral mucosa and in the _cul de sac_, and may be whitened for an instant by pressure through the eyelid. To expose the conjunctiva the right fore finger and thumb may be pressed on the upper and lower lids respectively of the left eye, and the left finger and thumb for the right, allowing them to slide backward above and below the eyeball. Another method is to seize the cilia and edge of the upper eyelid between the finger and thumb, and draw it downward and outward from the bulb, and then deftly invert it over the tip of the finger. In the old the unpigmented conjunctiva may appear yellow from the presence of subconjunctival fat, or this may appear at any age from hepatic disease (distomatosis) or icterus. It is swollen, or dropsical in anæmia, distomatosis, etc.

5th. =Examine the ciliary vessels whether they are congested or not.= These are distinguished from the conjunctival vessels in that they radiate in straight lines outward from the margin of the transparent cornea and do not move on the sclerotic under pressure. They are enlarged and very red in congestion of the ciliary circle and in iritis. In eyes devoid of pigment over the sclerotic, there is usually a circular, narrow, white zone between the congested area and the margin of the transparent cornea.

6th. =Examine the Membrana Nictitans.= See that its free margin is uniformly smooth, even, and thin and that there is no swelling, congestion nor morbid growth on any part of the structure.

7th. =See if the transparent cornea is perfectly and uniformly smooth, transparent and glistening and if it reflects clear, erect images of all objects in front of it.= The image of a round object which shows any irregularity in the curvature of its margin implies a deviation from an uniform curvature of the cornea: the image narrows in the direction of the smaller arc and broadens in the direction of the larger one (see keratoscopy, and corneal astigmatism).

8th. =A foreign body on or in the cornea= may be recognized in a good light, but better and more certainly under focal oblique illumination (see this heading).

9th. =A corneal ulcer= may be similarly recognized. It is made more strikingly manifest by instilling into the lower _cul de sac_ a drop of a solution of fluorescin and rubbing it over the eye by moving the eyelids with the finger. This will stain the whole cornea. If now the excess of stain is washed away by a few drops of boric acid, the healthy part of the cornea is cleared up and the ulcer retains a bright yellowish green tint.

10th. =Opacity or Floating objects in the aqueous humor= (flocculi of lymph, pus, pigment, blood, worms) are always to be looked for. They may be detected by placing the eye in a favorable light. They may be still more clearly shown under _focal illumination_ (see below).

11th. =Changes in the iris and pupil= may also be noticed in a good light. The surface should be dark in the horse, and of the various lighter shades in the smaller animals, but in all alike clear, smooth and polished, without variation of shade in spots or patches and without bulging or irregularity at intervals. Apart from the congenital absence of pigment in whole or in part, which may be found in certain sound eyes, a total or partial change of the dark iris of the horse to a lighter red, brown or yellow shade implies congestion, inflammation, or exudation. The =corpora nigra= in the larger quadrupeds should be unbroken, smooth, rounded, projecting masses outside the free border of the upper portion of the iris. It should show a clear, polished surface like the rest of the iris. =The pupil= should be evenly oval with its long diameter transversely (horse, ruminant), circular (pig, dog, bird), or round with an elliptical outline on contracting and the long diameter vertical (cat). It should contract promptly in light and dilate as quickly in darkness. Place the patient before a window, cover one eye so as to exclude light, then cover the other eye with the hand and quickly withdraw. The pupil should be widely dilated when the hand is withdrawn and should promptly contract, and it should actively widen and narrow alternately until the proper accommodation has been secured. Any failure to show these movements implies a lesion in the brain, optic nerve, or eye which impairs or paralyzes vision, interferes with accommodation or imprisons the iris. In locomotor ataxia the pupil contracts in accommodation to distance, but not in response to light.

12th. =Other causes of pupillary immobility= include: (a) Permanence of a pupillary membrane, which has remained from the fœtal condition and may be recognized by oblique focal illumination and invariability of the pupil: (b) Adhesion of the iris to the capsule of the lens—complete or partial—in the latter case the adherent portion only remains fixed, while the remainder expands and contracts, giving rise to distortions and variations from the smoothly curved outline: (c) Adhesion of the iris to the back of the cornea—complete or partial—and leading to similar distortions: (d) Glaucoma in which intraocular pressure determines a permanent dilatation of the pupil and depression of the optic disc: (e) The pupil is narrowed in iritis, and is less responsive to atropia or other mydriatic: (f) Lesions of the oculo-motor nerve may paralyze the iris and fix the pupil. The first three and the fifth of these conditions may be recognized by the naked eye, alone, or with the aid of focal illumination, the fourth may require the aid of the ophthalmoscope and the sixth which cannot be reached by such methods, might in exceptional cases be betrayed by other disorders of the oculo-motor nerve (dropping of the upper eyelid, protrusion of the eyeball, squinting outward).

13th. =Coloboma= (_fenestrated iris_), and =lacerated iris= are recognizable by the naked eye in a good light, or by the aid of focal illumination.

14th. =Tension of the eyeball= (_Tonometry_). Elaborate instruments constructed for ascertaining ocular tension are of very little use in the lower animals. The simplest and most practicable method is with the two index fingers placed on the upper lid to press the eyeball downward upon the wall of the orbit using the one finger alternately with the other as if in search of fluctuation. The other fingers rest on the margin of the orbit. All normal eyes have about the same measure of tension and one can use his own eye as a means of comparison. The educated touch is essential. In increased tension, the sense of hardness and resistance, and the indisposition to become indented on pressure is present in the early stages of internal ophthalmias (iritis, choroiditis, retinitis), phlegmon of the eyeball, glaucoma, hydrophthalmos, and tumors of the bulb.

Oblique Focal Illumination.

This is so essential to clear and definite conclusions and is so easily practiced on the domestic animals that every veterinarian should make himself familiar with the method. The method is based on the fact that when two perfectly transparent media touch each other a reflection of luminous rays takes place only at the surface. But in case any opacity exists in any part of the thickness of one of these media, it reflects the rays from its surface no matter what may be its position in the medium. Thus corneal opacities appear as gray blotches and under careful focal illumination it may be determined whether these are on the conjunctival surface, in the superficial or deeper layers of the cornea or in the membrane of Descemet. Similarly cloudiness or floating objects in the aqueous, reflect the luminous rays, and so with opacities in the lens or its capsule, or in the vitreous. In the same way the surface of the iris and corpora nigra may be carefully scrutinized. For satisfactory examination of the media, back of the iris, the pupil should be first dilated, by instillation under the lid of a drop or two of a 3 per cent. solution of atropia, and the examination proceeded with twenty minutes later. Homatropin is preferable to atropin as being less persistent in its action, and less liable to produce conjunctivitis. If it fails to produce the requisite dilatation, it may be followed by a drop of a 4 per cent. solution of hydrochloride of cocaine, which will secure a free dilatation, lasting only for one day in place of seven days as with atropin. The cocaine further removes pain and favors the full eversion of the eyelids.

The instruments required for focal illumination are a biconvex lens of 15 to 20 diopters, and a good oil lamp or movable gas jet. The light of the sun is not satisfactory. The examination ought to be conducted in a dark room, or less satisfactorily in semi-darkness. The lamp is held by an assistant at the level of the eye to be examined, either in front or behind, or first one and then the other, so that the rays of light may fall upon the eye obliquely. If the lids are kept closed it may be necessary to expose the cornea by pressing on the lids with the finger and thumb. The light is held 8 or 10 inches from the eye and the lens is interposed between it and the eye and moved nearer and more distant until the clearest illumination has been obtained of the point to be examined. In this way every accessible part of the eye may be examined in turn. The examiner may make his results more satisfactory by observing the illuminated surface through a lens magnifying three or four diameters. It is important to observe that the eye of the operator must be in the direct line of reflection of the pencil of light.

=Cornea.= By focusing the light in succession over the different parts of the surface of the cornea, all inflammations, vascularities, opacities, ulcers, and cicatrices will be shown and their outlines clearly defined. By illuminating the deeper layers of the cornea proper, the lesions of keratitis, opacities, ulcers and cicatrices will be shown. To complete the examination of the cornea the light should be focused upon the iris so that it may be reflected back through the cornea. This will reveal the most minute blood-vessels, any cell concretions on Descemet’s membrane, or any foreign body in the cornea which may have been overlooked.

=Aqueous Humor.= Unless the cornea is densely opaque, the anterior chamber can be satisfactorily explored by the oblique focal illumination. The cloudiness or milkiness of iritis or choroiditis furnishes a strong reflection from its free particles of floating matter, its blood and pus globules, and its flocculi of fibrine. The latter have usually a whitish reflection, the blood elements a red (hypohæma), and the pus a yellow (hypopion). The writhing movements of a filaria scarcely need this mode of diagnosis. Sometimes, and especially in the horse, detached flocculi of black pigment are found floating free in the aqueous and are highly characteristic.

By this illumination one can easily determine the distance of the cornea from the iris and lens (depth of anterior chamber) which is lessened by the forward displacement of iris and lens in undue tension in the vitreous (glaucoma, retinitis, tumors, bladderworms), or of the iris alone, in irido-choroiditis with accumulation of exudate in the posterior chamber of the aqueous. The depth of the anterior chamber may increase in cases of luxation or absence of the lens or softening and atrophy of the vitreous.

The adhesion of the iris to the back of the cornea may be satisfactorily demonstrated by focal illumination.

=Iris.= The lesions of the iris are exceedingly common in connection with recurring ophthalmia in the horse, and examinations in the intervals between attacks are of the greatest importance. The eye should be examined as already stated, at a window or door, and if available by the aid of a mirror. Any changes in form or color, or luster should be carefully noted, any tension of the eyeball, or angularity of the upper lid, and any slight blue opacity round the margin of the cornea. Then the prompt or tardy response of iris and pupil to light and darkness must be made out. To complete the test the eye should be treated with homatropin for three-quarters of an hour and with cocaine for ten or fifteen minutes, and then subjected to oblique focal illumination.

With partial posterior synechia the rest of the pupil is found dilated while the attached portion extends inward remaining fixed to the capsule of the lens. If the synechia is complete no dilatation whatever has occurred. The edges of the adherent iris extend inward as adherent projections, and any exposed portion of the lens is likely to show black points, the seat of previous adhesions that have been broken up. In such cases the periphery of the iris bulges forward from the accumulation behind it of aqueous humor or inflammatory exudate which cannot escape. The discoloration of the iris as the result of inflammation, stands out more definitely under the fuller illumination.

=Crystalline lens.= In exploring the crystalline lens or its capsule for opacities (cataracts) oblique focal illumination can be employed to the very best advantage, if the pupil has first been widely dilated by homatropine and cocaine. The light is concentrated on all parts of the anterior capsule in turn, then in succession on the different layers of the lens at all points and finally on the posterior capsule. The striking reflection from any points of opacity whether pigmentary, gray or pearly white is diagnostic, not only of cataract, but of its exact position—anterior or posterior, capsular or lenticular.

=Purkinje-Sanson images.= If the flame of a candle is passed in front of the eye, at a suitable distance, in a darkened room, and the observer looks into the eye obliquely from the opposite side, he observes three images of the flame, reflected respectively from the front of the cornea, from the anterior surface of the lens and from the back of the lens. The image from the cornea is erect, bright and clearly defined: that from the front of the lens is still erect, but larger and dimmer, because the difference between the index of refraction of the aqueous and lens is very slight: the third image, which is smaller and clearer than the last, is inverted, because the surface of reflection on the back of the lens acts as a concave mirror. The beginner may at first find it difficult to make out the image from the front of the lens but with a little care he can do so, and then by moving the light he should cause each image to pass over all parts of the reflecting surface in turn. Any unevenness or opacity at any point of the reflecting surface, will cause the image reflected from it to become blurred or diffused as it passes over it and thus, not the existence only, but the exact seat of such opacity is easily demonstrated. Opacities on the cornea cause blurring of the bright, erect image of the flame as it passes over that part: opacities on the anterior capsule of the lens blur the dim, erect image when passed over them: finally, opacities in the body of the lens or on its posterior capsule, blur the small inverted image as it passes over them.

Add to this method the oblique focal illumination and the images of the flame reflected from the three mirror surfaces (cornea, anterior and posterior lens surfaces) are made much clearer and more distinct than in any other way. To do this effectively the convex lens should be held so as to focus the flame in the air nearly in front of the cornea. The Purkinje-Sanson images are made very definite and clear. If the lens is approached nearer to the eye so as to throw the image of the flame within or behind the lens, a gray phosphorescent streak of light is seen in the depth of the pupil. This is due to the laminated structure of the lens as well as to the fact that the lens itself is not perfectly transparent even in its normal condition. The absence of the lens or its dislocation and displacement downward, below the line of vision may be inferred from the absence of this gray luminous reflection under this test.

OPHTHALMOSCOPE.

Principle of ophthalmoscope: Angle of incidence and angle of
reflection in same line, light close to one side of the eye, reflected
into it by a mirror, having a hole in the centre for eye of observer.
Opacities show a dense white in transparent media: if in front of lens
move with rolling of eye: if behind in opposite direction. To see
fundus must use biconvex lens. Emmetropic eye: myopic: hypermetropic.
Static refraction. Mydriatics: Atropine, homatropine, daturine,
duboisine, hyoscyamine.

In the healthy eye, the pupil and iris, and in cataract, even the opaque anterior capsule of the lens, can be clearly seen. The reflection of the pupil, however, is dark and no object back of the iris can be observed. The reason of the difference is that the rays of light, entering through the whole cornea, are reflected at the same angle at which they strike the surface of the iris. The angle of incidence is the same as the angle of reflection. In the hollow fundus of the eye, however, the light entering through the narrow pupil, strikes the fundus at a point which is hidden from the observer, behind the iris, and being reflected by the concave fundus, in exactly the same line along which it entered, it remains invisible. To illuminate the fundus of the eye, for the observer, his line of vision must be made exactly the same as that in which the pencil of light enters the fundus. This is best effected by reflecting the light into the eye by the aid of a small plane or concave mirror having a hole in the center through which the observer looks into the pupil. The concave mirror gives the stronger illumination, but the plane article is more easily manipulated and tends to cause less active contractions of the pupil. This is the simplest form of ophthalmoscope. For careful examination of the fundus of the eye, it is best to have the subject in a dark chamber, with a single large flame of an oil lamp or gas (electric light with an obscure globe may answer). The light is held behind and on the same side as the eye to be examined, at the level of the eye and the perforated mirror and the eye of the observer are kept from 10 to 20 inches in front of the eye and also at the same level. For the horse or ox under favorable conditions in a stall, the light of day coming from a fansash over the door may serve the purpose. Nicholas assures us that it may be accomplished even under the shadow of a shed or a tree. In such a case it is better not to have too much glare of light as the reflection from cornea and lens may prevent accurate observation. A somewhat cloudy day may therefore prove advantageous.

In focusing the reflected light on the cornea, and then on the pupil and lens, any opacities in these will be shown as a grayish nebular reflection or a denser white according to their degree of opacity. The opacities in the cornea or aqueous, in front of the axis of vision in the lens move in the same direction and to the same degree as the eye rolls, while opacities on the posterior capsule or in the vitreous, move in a direction opposite to the motions of the eye, and to a degree corresponding to their distance back of the lens. Thus if the eye looks downward such opacities move upward; if it looks upward they move downward; if it looks inward they move outward; and if it looks outward they move inward.

To secure an image of the fundus of the eye, including the entrance of the optic nerve (optic papilla), the tapetum, the pigmentary surface and retina and vessels, accommodation must be made for the normal refraction of the eye of the patient, and even for that of the observer.

In the =emmetropic= (normal) eye, the rays leave the surface of the cornea parallel to each other and it may be possible for the observer to secure a good image on his retina, without the aid of lenses. In the =myopic= (short sighted) eye they assume a convergent course on leaving the cornea, and to secure a satisfactory image a biconcave or plano-concave lens must be interposed between the cornea of the patient and the eye of the observer.

In the =hypermetropic= (long sighted) eye, the rays diverge in leaving the cornea of the patient, and a convex lens must be interposed between this and the eye of the observer, in order that the rays may be focused on the eye of the observer.

To adapt the vision to the different eyes the modern ophthalmoscope is furnished with a series of lenses concave and convex, any one of which can be moved behind the hole in the mirror to suit the demands of the particular case.

To make a satisfactory examination the pupil should be dilated as for oblique focal illumination. A 1:200 solution of apomorphia may be instilled into the eye (a drop or two) and in 20 to 25 minutes a satisfactory dilatation will have been secured. The effect of the homatropin will usually have disappeared in twenty-four hours.

Determination of Static Refraction.

This can be best done in the lower animals by determining the strength of the lens required to render clear the image of its fundus. By knowing the refracting power of the lens, we may ascertain what deviation from the normal refraction there is in the eye under observation.

In making this test the mirror of the ophthalmoscope must be brought closely to the eye of the patient—1 to 2 inches.

If in such a case and without the use of any lens a distinct image of the fundus is obtained, and if this is rendered less distinct by interposing the lowest convex lens in front of the eye of the observer, the eye is =emmetropic=.

If the ophthalmoscopic mirror without a lens gives an indistinct vision of the fundus, and if the image is rendered clear by interposing one of the convex lenses, the eye is =hypermetropic=. The strength of the convex lens, +1, +2 or +3, dioptrics will give the measure of the hypermetropia.

If, on the contrary, the ophthalmoscopic mirror gives an indistinct image of the fundus, which is rendered even more indistinct by the interposition of a convex lens, but is cleared up and rendered definite by a concave lens, the patient is myopic. The strength of the concave lens used will give the degree of _myopia_, –1 dioptric, –2 dioptrics, etc.

The tendency in the horse is constantly to slight long-sightedness, but the deviation is rarely found to be serious either in this direction or in that of astigmatism.

Mydriatics.

Dilation of the pupil by mydriatics (mydriasis dilation of the pupil) is a most important means of diagnosis, and therefore a knowledge of the action of the different mydriatics is essential. The mydriatics in common use not only dilate the pupil, but also paralyze the ciliary body and the power of accommodation in ratio with the strength of the solution employed. This determines an adaptation of the eye to the farthest point of vision and holds it there until the action of the mydriatic passes off and normal power of accommodation is restored. In short it renders the subject long sighted, during its action.

=Atropine= the alkaloid of atropa belladonna is the most generally available and persistent of the mydriatics, and is in most common use. It is usually employed as sulphate of atropine, though some prefer the nitrate, the salicylate or the borate to obviate the danger of atropinism. This form of poisoning may show in the occurrence of conjunctivitis and in case of one attack the susceptibility to atropine is greatly to be dreaded, so that it should never again be used on the same subject. The real cause of atropinism is uncertain, it has been variously ascribed to too great acidity or alkalinity, or to micro-organisms growing in the solution. Hence the importance of using the antiseptic salts of atropine, and of testing the solution to see that it is exactly neutral before it is applied.

The strength of the solution of atropine is an important consideration. Donders found that 1:120 of water produced a full effect, while Jaarsma obtained the full effect in one hour from a drop of a solution of one to twelve hundred of water. The action on carnivora (dogs and cats) is equivalent to that on man, while on the herbivora (rabbit, horse, ox, sheep) it is somewhat less, and on birds very slight indeed. On diseased eyes a large amount may be required, and with synechia (adhesion of the iris to the capsule of the lens) dilatation may be impossible. The full effect may last 24 hours, and accommodation may remain very imperfect for 11 days.

The direct action of atropine on the eye is shown in dilatation of the pupil of the frog after the eye has been detached from all connection with heart or brain, by excision. It acts also in the normal system through reflex nervous action, since, after division of the sympathetic trunk going to the eye, that eye does not dilate so much under atropia as the opposite eye.

Atropine is usually employed by lodging a drop in the pouch of the conjunctiva (inside the lower lid), and from this it makes its way into the aqueous humor, for if that liquid is transferred to the conjunctiva of another animal it causes dilatation. Puncture of the cornea with evacuation of the aqueous humor lessens the action of the atropine. Atropine dilatation is increased by following it with cocaine which causes contraction of the iridian vessels, the antithesis of the dilatation of the vessels which occurs when the cornea is perforated and the pressure of the aqueous humor is removed.

Atropine is one of the most potent poisons and must be used with caution especially in the carnivora and omnivora. The danger lies not alone in the absorption from the conjunctiva, but also from the escape of the liquid through the lachrymo-nasal duct, to the nose and later to the actively absorbing mucosæ of the lungs and stomach.

The symptoms of general poisoning are: rapid pulse, vertigo, weakness of posterior limbs, general prostration and thirst or dryness of the throat.

=Homatropine= is an oily liquid produced by the action of muriatic acid on the cyanate of atropine. With hydrobromic acid it forms a readily crystallizable salt, the solution of which acts on the eye like atropine, but more promptly and transiently. One drop of a solution of one to one hundred and twenty, usually gives in twenty minutes, full pupillary dilation and complete paralysis of accommodation which lasts only for twenty-four hours. Add to this that there is little danger of constitutional disturbance and poisoning, and homatropine must be accepted as a more desirable agent than atropine. It is especially to be preferred in cases of senility with shallow anterior chambers, and in glaucoma, in which atropine tends to aggravate the lesion.

=Daturine=, the alkaloid of datura stramonium is a potent mydriatic, causing pupillary dilatation in a solution of one to one hundred and sixty thousand of water. It appears to be identical with atropine.

=Duboisine= the alkaloid of duboisia myoporoides is also a potent mydriatic. Jaarsma found that a solution of the sulphate, of one to three thousand, paralyzed accommodation for twenty-four hours. It acts more promptly than atropine but is more poisonous.

=Hyoscyamin=, the alkaloid of hyoscyamus niger, is also strongly mydriatic. One drop of an one to three hundred solution of the sulphate paralyzed accommodation for from seventy-five to one hundred hours. Risley found it to act more promptly than atropine, and to be less dangerous than duboisine.

WOUNDS OF THE EYELIDS.

Traumas: bites, lacerations, blows, penetrating wounds, gunshot,
scratches, kicks. Upper lid or commissure. Reparatory power of eyelid.
Danger of distortion. Treatment: sutures, plaster, shellac, collodion,
gelatine, Frick’s gelatine, birdlime, sterilisation: Quilled and
twisted suture. Position in stall. Metallic guard for eye.

_Causes._ Traumatic injuries of the eyelids are especially common in the horse mainly because of his exposure in connection with the services required of him. In a team he is liable to be bitten by one of his fellows, or the lid may be caught on nails, in turning, or on hooks upon harness, chains or wagons. It is sometimes injured by a blow from a club or whiplash, or by knocking the head against solid objects that he failed to see on account of the blinds. Again the injury will come from running against prongs of bushes or trees, or of stump fences. Occasionally a blow with the horn of an ox or cow is the cause, but this is much more frequent with the bovine races. Then again gunshot wounds are found in all animals. In sheep the eyelids sometimes suffer from bites of dogs, while in dogs and cats, the teeth and claws are the main causes of injury. These smaller animals also suffer from brutal blows and kicks.

_Nature._ Wounds of the eyelids almost invariably affect the upper lid, because of its extra size and prominence. Sometimes one commissure or the lower lid is the injured part.

Clean incised wounds are rare, while lacerations with or without contusions are the common experience. The laceration often extends through the free margin of the lid, and then to one side, mostly the outer, in a direction more or less parallel to the tarsus. The result is that the detached flap drops downward exposing a greater or less portion of the bulb covered with blood. The conjunctiva, the cornea, the sclerotic or iris may be implicated in the lesion in different cases, so that such wounds are of the most varied degree of gravity. If, however, the lesion is confined to the lid, and in the absence of absolute detachment of the flap, or severe contusion, a good repair may be confidently hoped for. The vascularity and reparatory powers of the eyelid are unusually great, and the looseness of the skin, connective tissue, mucosa, and even the muscles is such that they do not draw injuriously upon the edges of the wound to disturb the process of cicatrization. If the two opposing ends of the divided tarsal cartilage are kept in accurate opposition, the elasticity of his structure serves to preserve the even contour of the palpebral margin, and the adhesion or granulation process between the edges of the wound, soon becomes firm enough to prevent further displacement. Even when one-half of the eyelid is torn loose, remaining attached only by a narrow portion, reunion without any unsightly distortion is not to be despaired of. In case of a mere vertical laceration on the other hand, the case is very simple and hopeful. Even when a portion of a lid has been completely torn off and lost, the loose textures of the remaining part, often appear to stretch in the process of healing so that a fairly serviceable, though by no means an æsthetic covering for the eye may remain. This may serve for a common work horse, but the unsightliness would necessarily debar him from use in a carriage or as a saddle horse. The imperfect protection too, exposes the eye to rainstorms, hail and snow, as well as to dust, and greatly predisposes to conjunctivitis.

_Treatment._ One can trust implicitly to the extraordinary reparatory power of the eyelids, yet so unsightly is any distortion of these parts, that the greatest pains must be taken to obviate loss of substance, or unevenness or puckering in healing. The points to be mainly sought for are the perfect coaptation of the divided edges, and the restraining of the patient from interrupting the healing process and breaking loose the forming adhesions, by rubbing the eye.

Inconsiderable wounds of the skin may be simply stitched together with sterilized catgut. Then the intervals between the stitches may be approximated, dried, and covered with strips of sticking plaster, or with shellac, collodion or gelatine. Frick’s gelatine is made by dissolving fine gelatine in a 1 per cent. solution of corrosive sublimate and adding about 10 per cent. of glycerine, perfecting the admixture by the aid of heat. When wanted for use it may be melted by heat and applied on the skin with a camel’s hair brush. Bird lime may be used as a substitute. Sterilization must be sought by the use of sublimate lotion 1:2000, or boric acid 2:100. Formerly the edges were kept in close opposition by the use of quilled sutures, the stitches passed around the quills being inserted at the usual distances while the quills, applied against the edges of the wound kept them smooth and even and obviated puckering. Or, perhaps better, the twisted suture may be employed, the edges being brought together by pins placed close together and a silk thread carried around each in figure of 8, and spirally from pin to pin along the entire length. If one pin comes out it ought to be promptly replaced and the whole left in place until a firm adhesion is established. The points of the pins are cut off short so that there may be no risk of their pricking.

With any method the horse or ox may be turned in his stall so that his tail may be toward the manger and his face outward, and he may be tied by two halters to the two posts, right and left. His food may be furnished in a sack hung from the ceiling and cut down one side. In this way the animal may be absolutely prevented from rubbing the itching sore against any solid body, and thereby interrupting the healing process. Another method is to apply a hood of stiff material with a metallic guard for the face, having bars extending from above downward and arched outward so that they shall effectually protect the eye in any attempt at rubbing.

DEFICIENCY OF THE EYELIDS. COLOBOMA PALPEBRARUM.

The term coloboma representing merely a hiatus or deficiency is
applied to different parts of the eye according as there may be a lack
of substance of the part in question:—=Coloboma palpebrarum=
(deficiency of the palpebræ or lids), =C. iridis= (perforation of the
iris), and =C. choroideæ= (partial absence of the choroid).

=Coloboma palpebrarum= is usually congenital and takes the form of a vertical notch on the upper lid, separating its two lateral parts into independent flaps. According to the breadth and depth of the notch are the extent of the exposure of the bulbar conjunctiva and the liability to irritation and infection by foreign bodies. The same condition of things will occur traumatically and require identical measures of repair. These consist in paring the edges of the notch and bringing them accurately together with catgut, silk or quilled suture, the approximation being rendered more perfect by the application of collodion, shellac or gelatine mixture (see wounds of eyelids). The vascularity and extensibility of the tissues of the lids greatly favor a kindly healing. Rubbing of the eye must be guarded against as advised under wounds of the eyelids.

ORGANIC UNION OF THE EYELIDS. ANKYLOBLEPHARON. NARROWED FISSURE BETWEEN
THE LIDS. BLEPHAROPHYMOSIS.

Complete closure of the palpebral fissure has been seen as a congenital infirmity in sheep, dogs and cats, while the partial closure has been found in all classes of animals as the result of chronic conjunctivitis and contraction of the exudation in undergoing organization. Narrowing of the fissure gives the appearance of a small eye, so that a progressive diminution is usually supposed to come from a reduction in size of the bulb, though no actual atrophy of that organ has taken place. In drooping of the upper lid (ptosis) too, the fissure is reduced and the illusion of an atrophy of the eyeball is induced. The closure of the fissure may come from _blepharospasm_, as the result of irritants in the eye, or even of nervous disorder.

_Treatment._ In case of complete closure of the palpebral fissure, the skin is picked up with forceps and an incision is made between the two tarsi into the conjunctival sac. Then with probe pointed scissors, or a grooved director and bistuory the incision is carried between the tarsi to the proper position for the internal and external canthi. During healing the lids should be frequently bathed with a boric acid solution, and an ointment of the same with vaseline should be applied to prevent adhesion.

When the trouble consists in a drawing together of the skin at the outer canthus, the result of inflammation, the adhesions are separated by a horizontal incision leading outward from the line of the angle. The edges of the conjunctiva and skin are then sutured together, so as to prevent further adhesion and the part treated as an ordinary wound. This is known as _canthoplasty_.

Ptosis coming from tumors on the lid, or excess of fat in its substance, or from oculo-motor disease must be treated according to indications. The same remark applies to _spasm_ of the orbicular muscle (_blepharospasm_), whether clonic or tonic. In domestic animals the removal of the cause (foreign body, eyelash), will usually succeed.

WIDENED PALPEBRAL FISSURE.

After wounds of the outer canthus the union of the edges may remain imperfect so that the fissure is enlarged and the eye unduly exposed. The case is still worse if the wound has deviated from the horizontal and has involved the orbicular muscle, the divided ends of which continue to draw the edges apart, and cause a constant overflow of tears (epiphora). Enlargement of the bulb or its protrusion by reason of a swelling beneath it may give rise to the same appearance (exophthalmos).

_Treatment._ Pare the edges of the upper and lower lids at the outer canthus and bring them together by sutures.

LAGOPHTHALMOS. INABILITY TO CLOSE EYELIDS.

This is called _hare-eye_ (lagos, hare) from the fact that the hare habitually keeps the eyelids open. It is mostly due to spasm of the levatores palpebræ, or to undue size of the orbicular opening. It may, however, accompany ectropion, exophthalmos, and enlargement or swelling of the eyeball from any cause. Bayer has seen cases in diseases of the trifacial nerve, in neoplasms in the orbit and in buphthalmus.

Cases of the kind are especially liable to irritation, inflammation and ulceration due to foreign bodies falling on the exposed bulb.

The _treatment_ is largely that of the attendant condition ectropion, tumor, etc., which may be consulted.

ADHESION OF THE EYELID TO THE BULB. SYMBLEPHARON.

Causes: Conjunctivitis, burns, operation and other wounds. In front of
or behind the reflection of the mucosa from eye to lid. Prevention.
Treatment: section of adhesion, and vaseline, etc., Two edges of
healthy mucosa sutured together over the sore. When fornix is
implicated mucosa is transplanted.

This is liable to occur to a greater or less extent, in all animals, in connection with violent conjunctivitis, burns and operation and other wounds. It has been divided into _anterior_ and _posterior symblepharon_, the former being an union in front of the normal reflection of the conjunctiva from the lid upon the bulb (fornix), and the latter involving the fornix in the substance of the adhesion. The _anterior_ form by anchoring the lid to the eyeball is much more likely to induce blindness, but it has the compensation that the union may be broken up and the parts healed without subsequent reunion. In the posterior form the eye can be better exposed and vision retained, its repair is much more difficult demanding transplantation of skin or mucous membrane on to the sore, and even then the granulation tissue being continuous from bulb to eyelid may so contract in healing as to leave matters no better than before.

These adhesions not only restrict the movements of the lids, preventing their opening and the exposure of the bulb, but they also anchor the bulb itself, and hamper its movements, necessitated for vision. In all cases therefore of wounds, burns, abrasions and ulcers, of the palpebral and bulbar mucosæ it is highly important to take precautions against the formation of such connections. Any forming adhesions must be broken up day by day and the surfaces must be kept apart in the intervals by borated or iodoformed vaseline.

In a small anterior symblepharon the connections may be cut through and subsequent adhesion prevented by the frequent introduction of iodoformed vaseline, and if need be, by the daily separation of the surfaces by a probe. When this fails a plastic operation may be resorted to, the mucosa on the inner side of the lid being incised in a vertical direction a short distance on each side of the sore and the inner edges accurately stitched together. The raw surface left on the bulb thus comes in contact only with the healthy mucous strips on the eyelid, which have been drawn together over the seat of the former sore, and the two new raw surfaces formed on the lid are well to each side of the sore on the bulb, and are in contact with its healthy mucosa only. Thus no two raw surfaces can come in contact, and adhesion is obviated.

When the fornix is implicated mucous membrane from the mouth, vulva, the bronchia of the rabbit, or the skin of the frog must be transplanted after the requisite incision of the cicatrix has been made.

INFLAMMATION OF THE EYELIDS. BLEPHARITIS.

Phlegmon. Causes: traumas, skin disease. Symptoms: swelling, redness,
distortion, infiltration, semi-closed lids, scabs, sloughs, abscess.
Tenderness. Itching. In eczema papules, vesicles, weeping eye.
Treatment: antiseptic astringent lotions, almond oil, vaseline, zinc
oxide, salicylic acid, boric acid, starch, xeroform, pyoktannin; for
eczema, mercury oxides, silver nitrate.

Conjunctivitis will be treated later, and under the present head there will be considered only the phlegmon of the outer structures.

_Causes._ This lesion may come from two distinct causes, traumatism and skin disease. The traumatisms in _horses_ and _cattle_ are bruises sustained in rolling, especially during colics, in striking the head against posts, poles, shafts and other solid bodies, in enduring blows with horns or clubs, or frictions by the halter or in putting on a collar. _Dogs_ suffer especially from blows with clubs and kicks from men or animals. _All_ may suffer from wounds of the lids, and from extensions of eczema and other skin diseases.

The _symptoms_ consist in swelling, redness, distortion, and often extensive infiltration of the lid, sometimes eversion with exposure of the reddened conjunctiva, usually abrasion, contusion, puncture or laceration, semi-closed eye, the upper eyelid being comparatively immovable (ptosis), and the formation of scabs, sloughs, or abscess. There may be extreme tenderness, or, more commonly, intense itching. Where eczema exists there may be found minute shot like papules at times surmounted by small vesicles and the skin disease is continuous backward upon the face. When abscess forms, the rounded swelling and manifest fluctuation will betray its presence. Usually the eye waters and the side of the cheek is wet and the hairs matted by a whitish coagulated lymph and mucus.

_Treatment._ In the early stages without scabs, sloughs, or abscess, antiseptic astringent lotions are in place. Weak solutions of zinc sulphate, boric acid and morphine may be kept applied on a light bandage. Or silver nitrate 1 gram to 1 oz. water may be applied daily with a fine brush.

When scabs and crusts have formed they may be softened by the application of almond oil, and then removed. The surface may then be dusted with a bland antiseptic powder such as: zinc oxide 10 parts, salicylic acid 1 part; or boric acid and starch equal parts; or iodoform; or xeroform. Or unctuous applications may be used; zinc oxide 10, salicylic acid 1, vaseline 10; or iodoform 1, vaseline 5. Or a watery application may be used, such as the silver lotion or that of pyoktannin 1:1000.

For eczema yellow oxide of mercury 1, to vaseline 10, has an excellent reputation. It may be alternated with pyoktannin.

When abscess has formed it should be excised in a line parallel to the free border and the resulting cavity injected with the silver or the pyoktannin solution.

In all cases the patient must be fastened as for wounds of the lids so that he cannot rub the eye.

For eczema and other skin diseases the special treatment appropriate to the disease should not be omitted.

ŒDEMA OF EYELIDS.

In anthrax, malignant œdema, disease of heart, kidney or liver,
distomatosis, trichiniasis, wasp stings, urticaria, petechial fever.
Treatment: correct general disorder, remove local irritant, antiseptic
astringents.

An œdematous condition of the eyelids with or without inflammatory conditions may be due to local disease or it may be the result of more general disorder. In anthrax districts any of the herbivora, but especially cattle and sheep, are liable to a diffuse anthrax of the eyelid with a special petechial or brownish condition of the palpebral conjunctiva. Malignant œdema and other local bacteridian affections affect the loose textures of the eyelid in a similar manner, but with extrication of gas and crackling under pressure. Such cases are complicated by local inflammation. When in the absence of inflammation the lids pit on pressure, one should seek for some disease of the heart, kidney or liver, also for indications of similar dropsical effusions in other parts of the body. Distomatosis and, to a less extent, pulmonary and duodenal strongylosis are especially common factors in sheep. In distomatosis (liver rot) a simultaneous dropsy is often present in the intermaxillary space, the chest or the abdomen. The puffiness of the eye is especially marked in the palpebral conjunctiva, and is exposed by everting the eyelid over the tip of the finger. In trichinosis in man and less frequently in swine, dropsy of the eyelid is often present at the end of the first week. Other swellings of the lids partaking more of the nature of inflammation, result from the stings of wasps, hornets and other insects, from urticaria (in horses especially) and from petechial fever in solipeds.

In _treating_ such cases the general disorder, if present, must be first attended to, then the removal of any local irritant, and finally the antagonizing of any local inflammation or infection. Astringent and antiseptic lotions are especially called for.

EMPHYSEMA OF THE EYELIDS.

This has been already referred to as occurring in malignant œdema, black quarter and other gas producing infections. It may also come from lacerations made in puncturing the lachrymal sac, and from fracture of the margin of the orbit—the air entering the connective tissue in this case from the cavities of the nasal sinuses. The lid feels puffy and crackles when pressed and apart from a general infection it requires only soothing and antiseptic dressings.

DISEASE OF THE MEIBOMIAN GLANDS. BLEPHARADENITIS. SEBORRHŒA.

This is a blepharitis of the edges of the lids which are swollen, red, and incrusted along their margins with scabs and sebaceous concretions. When this scurf is removed the skin is found to be red, tender and glistening. The glands are the seat of congestion, and produce a modified secretion in excess, which dries into crusts instead of preserving its normal oleaginous consistency. As these glands open into the follicles of the eyelashes, their walls are implicated and shedding of the lashes is a common result. It may be assumed that this affection is often associated with the proliferation of microbes in the glands and gland ducts, while in other forms the presence of acari is the controlling factor. Wilson found the demodex folliculorum in the Meibomian glands of the horse, and Oschatz in those of the sheep.

_Treatment._ Smear the margins of the lids with vaseline and when the crusts have been thoroughly softened wash them off with Castile soap and warm water. Then dress the margin with the ointment of the yellow oxide of mercury 1, in vaseline 10. If demodex is suspected they may be squeezed out and the lids washed frequently with spirits of wine as a solvent.

HORDEOLUM. STYE. ACNE.

Like acne of the skin in general, this consists in inflammation and suppuration of a hair follicle and sebaceous gland. The whole lid or a large part of it may be swollen, but by stroking it with the finger, a hard, rounded, very tender spot will be detected and as the disease advances this develops a minute collection of pus. A specially wide orifice favors the entrance of the pus microbes, and the onset of the disease. It has been noted in dogs (Fröhner).

For abortive _treatment_ Fick recommends dry heat from a pocket handkerchief or a heated teaspoon. If pus is present it must be evacuated, and recurrence guarded against by cleanliness and antiseptics. Use pyoktannin solution (1 ∶ 1000), or mercuric chloride (1 ∶ 5000) or yellow oxide of mercury ointment.

CHALAZION.

This is a pea like tumor growing from the tarsal cartilage, its flattened side toward the mucosa, which is red and angry, and its round surface toward the skin. When manipulated between the fingers it moves with the tarsus. It is usually of slow growth and may continue for years apparently unchanged. Some have thought it tuberculous, but its true nature is uncertain. Warner records the disease in the horse.

_Treatment_ consists in incision and removal of the tumor, curretting of the cavity, and after antiseptic douching, suturing the lips.

TUBERCULOSIS OF THE EYELID.

Described by Jewsejenke in the lower lid of birds, this is manifested by small, hard round knots, covered by bluish red, or yellowish red skin, and when incised showing a characteristic miliary tubercle, with bacilli and sometimes a caseated centre. It is treated by incision, curretting and caustics.

TURNED IN EYELASH. TRICHIASIS.

Sometimes an eyelash grows inward so as to impinge upon the front of the eyeball, or even to extend between this and the eyelid. The condition exists in _entropion_ but _trichiasis_ is rather the deviation of one or two cilia by reason of their false direction, individually. It may occur as the result of a pre-existing inflammation affecting the edge of the lid and the follicle, and the offending hair is not only badly directed but small and shrunken as well. On this account it is not always easy to recognize it, and accordingly in cases of conjunctivitis without apparent cause it is well to examine carefully with the aid of oblique focal illumination.

_Treatment_ consists in pulling out the offending hair with ciliary forceps, avoiding bending it lest it break off short and become at once more irritating and more difficult of extraction. In case the hair grows anew in the same direction extract it anew and destroy its root with the electric cautery.

ENTROPION. TURNING IN OF THE EYELID.

In foals, puppies, hounds, with narrow fissure, and conjunctivitis, or
tarsitis. Permanent bandaging, orbicularis spasm. Symptoms:
disappearance of tarsus and lashes by involution. Treatment: in spasm
fix by plaster; suture skin; excise elliptical section of skin and
suture edges together. Release cicatrices.

Inversion of the eyelid or a portion of it, with consequent trichiasis, conjunctivitis and lachrymation has been met with congenitally in foals (Aubry, Bourdeau, Hamon) and puppies (Cadiot, Almy). Hounds have especially suffered. In the older animals it is largely determined by abnormally narrow fissure, and by old standing disease of the conjunctiva or tarsus, with cicatricial contraction or adhesion. Persistent bandaging turns in the cilia and contributes to entropion. Finally a persistent spasm of the orbicularis muscle may bring it about.

_Symptoms._ Trichiasis is usually, though not always, present.

In any case the tarsus is turned inward so as to press upon the front of the bulb, or even to disappear completely. Thickening and distortion of the lid is a not infrequent condition.

_Treatment._ In case of simple spasm clip or shave the hairs from the lid corresponding to the lesion, and close to the tarsus attach a strip of plaster. When firmly adherent draw it sufficiently to efface the entropion and attach it to the skin of the face.

This failing, Gaillard’s sutures may succeed. With a pair of forceps with looped, transversely elongated blades, pinch up skin and muscle sufficient to correct the entropion, and passing a needle twice through this fold with an interval of 3 mm., tie the suture over a small roll of cotton. The stitches may be removed in two days and the cicatrices may permanently obviate the deformity.