Nnrtli (Earolina BtnU Ilmupraitg HI erioris arises at the orbital apex, passing along the upper wall, becoming intermingled with the orbicularis in front of the tarsus. Some fibers go to the conjunctiva, while some become attached to the upper edge of the tarsus. Supplied by the motor-oculi. Function to raise the lid. The lower lid is supplied by a prolongation from the inferior rectus. The Tarsi. — The framework of the lids, being united together and to the adjacent bone by the internal and external lateral ligaments, gives rigidity and stabil- ity to the eyelids. Composed of fibrous condensed tissue. The Shhi adheres intimately to the orbicularis muscle ; smooth and covered with numerous fine short hairs. In the foetus, at the orbital arch, where the skin everywhere else is without hair, we find a well marked eyebrow. Fat is never found beneath this skin. The Conjunctiva is a delicate mucous membrane, which commences at the free border of the lid where it is continuous with the skin. It lines the inner surface VETERINARY OPHTHALMOLOGY. 27 of the lids and is reflected upon the globe, over which it passes and becomes con- tinuous with the cornea. The palpebral portion is thicker and more vascular ^^ than the ocular, and is The tarsi seen from behind. They have been isolated from other tissues and remain joined at the external and internal angles by the lateral ligaments, external and internal : 1, Posterior surface of tarsus superior; on its edge the openings of the Meibomian follicles; 2, tarsus inferior ; Sand 4, punctum lachrymiale superior and inferior ; 5, external angle ; G, internal angle. firmly attached to the tar- sus. ^Yhere it passes from the lids to the globe it is thin and very loose and forms the fornix conjunctivce. Now, as its name indicates, it joins the bulbus and pal- pebral together. It envelops, in addition to the above, the anterior portion of the haw {memhrana nictatcDis) ill a particular fold, and covers the caruncula lachry' malts and enters the puncta. At the margin of the cornea one may not trace it, although it is represented by a layer of pavement epithelium. At the surface of the caruncle it shows some very fine hair bulbs. (See conjunctiva.) Eyelashes (cilia.) — Two rows, at free borders of the lids. Act as a shield against foreign particles, dust, etc. Their follicles are surrounded by sebaceous glands and the glands of Moll (which are small tubular glands resembling ceruminous glands.) These various glands serve to lubricate the eye by 28 VETERINARY OPHTHALMOLOGY. their secretions, which emerge by minute orifices on the free border of the lids. The lashes are longer and stronger and more abundant in the upper lid. Though the lashes of the lower lid are few, they are reinforced by some long bristly hairs, which are just like the tentacular of the lips. The Meibomian Glands.— Analogous to sebaceous. They are lodged near the posterior surface of the tarsus, arranged like currants on a stem. They open by minute orifices upon the free border of the lids behind the cilia. Each gland consists of a central tube with a number of openings around its sides. The unctuous matter they secrete facilitates the retention of the tears over the conjunctivse. Supra-orbital, lachrymal and orbital branch of the superior dental arteries, forming thick network indirectly connected around the cornea with the ciliary system, through the episcleral, are the arteries. Lymphatics form a close network around the cornea. Nerves from the fifth pair enter at inner and outer angles of the eye, form a thick plexus and end free— some by club-shaped expansion. These nerve fibers are non-medullated, Membrana Nictatans.— " Third or winJcing eyelid:'^ Hem. At the inner angle of the eye. Its composition is of a fibro-cartilaginous framework, elastic, irregularly shaped, prismatic at its base, which is thick, and thin anteriorly, where it is covered by the conjunctiva. Behind is a strong cushion of adispose tissue, which is VETERINARY OPHTHALMOLOGY. £9 insinuated betireen all the muscles of the eye. The movements of the haw are mechanical, and no muscle directly causes them. When the eye is in repose but a small fold of conjunctiva is seen; the rest is in its fibrous case. When the eye is -withdravi^n into the orbit by contraction of the recti muscles, the globe compresses the fatty cushion belonging to the carti- lage; this cushion, pressing outwards, pushes the memhrana before it, and the latter then entirely con- ceals the front of the eye. This movement is instanta- neous, but it may be momentarily fixed by pressing gently on the eye when the animal retracts it within the orbital cavity. The use of the membrana is, as will be seen from the above, to maintain the healthy con- dition of the eye by removing any matters that have escaped the eyelids; and what clearly demonstrates this function is the inverse relation that always exists between the development of this body and the facility with which animals can rub their eyes with their ante- rior limbs ; so it is that, with the horse and the ox, whose thoracic member cannot be applied to this purpose, the membrana is very highly developed, and in the dog, which may use its paw to some extent when it requires to brush its eye, it is smaller ; in the cat it is still fess, while in the monkey and in mankind, whose hands are perfect, it is rudimentary. In tetanus, the membrana nictatans often remains permanently over the eye in consequence of the continued contraction of 30 VETERINARY OPHTHALMOLOGY. the recti muscles.* The gland of Harder, situated on the outer face of the haw, is a reddish-yellow gland^ covered by fibrous membrane and surrounded by fat. Secretes a thick unctuous matter, which gains exit on the inner face of the membrana by three or four open- ings. DISEASES OF THE LIDS. Acute Blepharitis. — Abscess of the lids. Is an acute phlegmonous inflammation of the lids ; usual cause is of a traumatic nature. May accompany strangles or follow it; adenitis simple. Will have great swell- ing with the cardinal symptoms ; apt to have con- junctivitis accompany this. May have fluctuation early. This might go on to gangrene. If early enough, cold applications to abort. If later, and suspect forma- tion of pus, hot applications, and get the matter over with. Of course, as soon as fluctuation is felt, open freely and mahe the incision parallel with the lid bor- der. Evacuate freely, using antisepsis and ascepsis (and Boric acid solution is good and safe about the eye) for patient and instruments. Do not use Hydrar for instruments, as you'll dull the edge quicker than it can be restored, and not more powerful than 1 to 5000 about the eye, unless great care is taken to prevent its entrance into the conjunctival sac. May suture if you think necessary ; compress bandage to insure first intention. * F. Lecoq in Chauveau's Anatomy. VETERINARY OPHTHALMOLOGY. 31 Blepharitis Ciliaris {Blepharitis Marginalise Tinea Tarsi^ Ophthalmia Tarsi). — Rarely met with in equine patients, but when it is, it is long-lasting and very rebel- lious. This may be merely a slight, scarcely perceptible redness of the lid margin, while again it may be very severe — ulcerations, or thickened everted edges. Caused by smoke, dust, cold winds, bright light and too much of it. Lids are apt to be agglutinated. Edge or margins scaly and scabby. Photophobia and lachry- mation. Hair follicles may be destroyed and the cilia fall out. The thickening and eversion of lids may cause ectropium. Always assure yourself it is not the result of Phthe- iriasis, for, if it is, it will be necessary to eradicate them before attempting a cure of the Blepharitis. Use Merc, ■ung. Fungus growths in the hair follicles are also said to cause this disease. Pemove the hairs by epilation, and go on to cure. Lachrymal catarrh, and particularly catarrh of the lachrymal sac, with stric- ture of the duct ; the tears, unable to get through into the nose, flowing over the lids. Tears being retained, inflammation ensues. In such cases ojien the cana- liculus into the sac and give free passage for the tears, then go on and treat as a simple case. It is very neces- sary to observe cleanliness. Removal of scales and scabs — without force. If can not get them away easily, poultice the eyes for fifteen or twenty minutes. Then proceed: Vaseline. Boric ac. and vaseline; gr. — xxx. 32 VETERINAllY OPHTHALMOLOGY. to one ounce ; — Oxide of zinc ointment. If it has gone on to ulceration, after removing the crusts gently, use hydrar. ox. flav, grs. two to vaseline one dram ; — or cit- ron ointment x or xx grs. to the dram, of vaseline. May cauterize the ulcers with a fine point of lunar caustic. Stye {Hordeolum). Acute inflammation of cellular tissue of the lids, with suppuration and pointing at the Fig. 16. Fig. VI. edge of the lids. This usually is found around a hair follicle and first appears as a circumscribed swelling. Some cases go on and involve the entire lid, which be- comes swollen and oedematous. Much severe throbbing pain. Often multiply and may return in successive crops. Usually break in a week. Some are absorbed and do not break. Incise if pointed, and evacuate. VETERINARY OPHTHALMOLOGY. 33 Will just mention here adroopinjjof the lid, due either to partial or complete paralysis of the levator palpebrse superioris. Is called Ptosis. If you should desire to correct, remove an elliptical portion of the skin and muscular fibers, and suture. (See Figs. 16 and 17). There is another condition which may be met with, called Blepharospasmtis^ and it is a spasmodic closure of the lids. May be due to a foreign body, ulcus corneae, iritis. Carious teeth. May be tonic; or clonic, lasting but a few seconds at a time, liemove the cause of irri- tation, which is the only treatment. Another rarety, called nictitation, which is a constant blinking, may be due to some irritation in the eye, or of a reflex character, from worms, decayed teeth, etc. Remove cause. Blspharophimosis is a narrowing of the palpebral opening, usually the result of chronic trachoma, and can be relieved by canthotomy, performed by inserting blunt pointed scissors in outer canthus and snipping as far as desired. Trichiasis and Distichiasis. — The fii'st is an irregu- larity in shape and disposition of the cilia. The second is a double row of cilia. Trkatmext : epilation. Entropium is an inversion of the eyelid, spasmodic and cicatricial. First usually in the lower lids ; comes from keratitis, foreign bodies, etc. Second is the result of granular and diphtheritic conjunctivitis, burns, etc., 3 84 VETERINARY OPHTHALMOLOGY. •where there has been loss of substance in the conjunc- tiva. In the spasmodic form may use adhesive plas- ter ; paint with collodion and keep the lid in position. Fig. 18. Represents a vertical section of the upper eyelid. S, supra orbital margin : to, fascia tarso-orbitalis ; po, parsorbitalis ; pc, pars ciliaris of orbicularis muscle ; t, tarsus ; c, eyelash ; f , lower border ; d, upper border of the ■wound ; a b, passage of suture through aponeurosis.— iVbi/es, In cicatricial, operative interference consists in re- moving a slight strip of skin parallel with the lid mar- gin and suturing, entering the suture on the conjunc- tival side of the lid and drawing the lips of the incision together. This will evert the lid. (See Fig. 18.) Ectropium. — E version of the eyelid may be slight or great. Two ioviins— cicatricial, due to con- traction after burns, abscesses, wounds, etc. ; conjimc- tival^ when due to chronic inflammation and swelling of the conjunctiva, which separates the lid margin from YETEEINAllY OPHTHALMOLOGY. 85 Fig. 19. the eye,sometimes aided by relaxation of the skia ' and spasm of the orbicu- laris muscle. The best results are obtained by the removal of a V- shaped piece of skin, and dissecting it aAvay. Bring the edges together so as to p? F.g. 31 YETERIXAEY OPHTHALMOLOGY. 63 or one form of different degree — i. e., a thin (tenne), and a thick {a-assum). Requires no treatment unless it extends upon the cornea so as to obstruct vision. May then be removed by (1) excision, which is dis- secting the growth off of the cornea and sclerotic, to a point near the canthus, and uniting the conjunctival wound by sutures; (2) tmnsj^lantation, which is per- formed by dissecting it off up to the base and then insert- ing it into an incision made in the conjunctiva, parallel to the lower edge of the cornea and retaining it there by sutures; or (3) ligature thread passed around the growth at two or more points, so as to cause stran- gulation. As the result of severe chronic conjunctivitis we meet with Jurojyhthalmia. Dryness of the eye. This is an atrophied condition, and of cicatrical change in the cornea, conjunctiva and sub-conjunctival tissues. The surface is of a dirty greenish or grayish color, or tendinous appearance. Also is dry, scaly, and stiff from destruction of secretory apparatus. Obliteration of the palpebral folds, and more or less adhesion of lid to globe. TREATiiEXT is inefficient. The dryness may be alle- viated by bland applications, such as milk, glycerine, vaseline, etc. Tumors of the Conjunctiva. — Pinguecula', a small yellowish tumor, fatty in appearance, situated near the corneal margin, and chiefly seen in the aged ; con- 64 VETERINARY OPHTHALMOLOGY. sists of hypertrophied conjunctiva and epithelium ; they are harmless and need no treatment. Dermoid tumors, smooth and yellowish, covered with con- junctiva and perhaps with short hairs ; composed of connective tissue and fat ; generally congenital. Ex- cise them. Warts, similar to those on prepuce, may occur on any part of the conjunctiva ; snip off with scissors. Cancer should be treated as elsewhere. CHAPTER Vn. THE CORXEA. Cornea is elliptical in shape, is perfectly trans- parent, which is clue to the arrangement as well as the transparency of its individual parts. It closes the anterior opening of the sclerotic and forms one-fifth of the external envelope which it completes. It fits into the sclerotic like the crystal of a watch into its case, the cornea being beveled on its outer edge. The cornea is composed offivelayers: (1) The anterior epithe- lial layer is, as its name indicates, composed of epithelia disposed in layers and continuous with that of the conjunctiva. (2) Boicman^s membrane. A very elastic tissue which possesses a tendency to curl up. Neither acids or boiling renders this layer opaque as it does the other layers. This layer has no lacunae nor lymph canals, but contains fibrillse and faciculi. Has no fixed cells or movable corpuscles. Is intimately ad- herent to the parenchyma. Cannot be separated as a distinct layer. (3) The parenchyma is composed of fine fibrillae united into fasciculi, bound together by a cement matter. Has a system of canals which are a continuation of lymphatic spaces. These lymphatic 5 65 66 VETERINAKY OPHTHALMOLOGY. canals contain cells. The fasciculi are in layers, one above the other. The canals in the cornea are hollowed out of the tissue formed by the cement and fasciculi, and may be resolved into shallow spaces, very numerous and communicating with each other by canaliculi, which vary in size and form a net-work throughout the parenchyma, penetrating between the fibers and ramifying from layer to layer. Their func- tion is to convey the nourishing lymph. Three varieties. •^^ of cells may be found in these canaliculi, fixed, wander- ing and pigment. The fixed lie in the lacunae, and send prolongations out into the canals. The vmnder- ing are brighter, larger, and, as the name implies, have power of motion. The pigment is found only at the periphery of the cornea. On the inner side of the tissue proper of the cornea is a lining membrane called (4) Mescemef s. It is firm, elastic, glossy in appearance and VETERINARY OPHTHALMOLOGY. 67 highly refractive. Then the (5) endothelial layer, com- posed of a single layer of cells. This layer is reflected, on the anterior surface of the Iris. In or on the cornea VETERINARY OPHTHALMOLOGY. 69 inflammation of adjacent parts, etc. ; is one of the most frequent diseases of the eye. It leads to vascularization, cell proliferation and suppuration, each of these con- ditions being more or less prominent according to the kind of inflammation present. Attending these con- ditions we find the vision is impaired, ciliary irritation, which is aliomjs ominous (a zone of fine vessels appearing around the corneal margin), pain, photophobia, lachry-. mation, conjunctival congestion and contraction of the pupil. The cornea will be turbid and swollen. If ulcerated, it becomes thinned, and perhaps rupturing permits deeper parts to become prolapsed or escape. If thinned or softened it may bulge forward from intra-ocular pressure, forming staphyloma. After recovery, indelible opacities and alterations of curvature may remain, with correspond- ing loss of vision. In treating acute corneal inflammations it Is the cardinal rule to avoid all irritants and caustics and to pay special attention to hygiene and general health. ^" Atropine, darkness, and rest of the eye are always proper. Cold and local bleeding may be tried if symp- toms are very acute. When the disease does not improve under this treatment, or becomes chronic, the proper treatment requires special experience. Where 70 VETEKINAEY OPHTHALMOLOGY. there is great photophobia, or spasm of the orbicularis^ the cold douche, forcible stretching apart of the lids, canthoplasty, insufflations of calomel, ointments of mercury, etc., are employed. Keratitis Vasculosa. — This is characterized by a grayish cloudiness of the cornea with network of vessels in the affected region. The epithelium may be shed, causing great pain from the exposure of nerves. Under favorable circumstances, tends to recovery. May, however, run on into other forms and be combined with them. Fig. 34. Phlyctenular Keratitis is characterized by phlyc- tenules in the superficial layers of the cornea like those in phlyctenular conjunctivitis. These phlyctenules appear as inflammatory nodules, singly or in groups, on any part of the cornea, but most often at the margin. May be surrounded by vesicles, which vesicles may VETERINARY OPHTHALMOLOGY. 71 burst and leave a ring ot ulcers. A triangular net- work of vessels will be seen running toward phl^^c- tenule, its base towards the retrotarsal fold and its apex at the phlyctenule, if this is at the edge of the cornea. If, however, the phlyctenule lies some distance from the corneal border, the apex of the triangle appears cut off at the edge of the cornea, thus leaving a space of clear tissue intervening between it and the phlyctenule. If the attack is severe, vascular keratitis may supervene, vessels then would extend upon the cornea quite up to the phlyctenule. The secretions from the eye irritate and excoriate the parts over which they flow. Interstitial Keratitis. — Also termed Parenchymatoxis and Difficse. Will have swelling and diffuse cloudi- ness, which cloudiness usually extends from margin to center, and very rarely the reverse. May be very sliglit, and again may be very dense, simulating ground glass. May be irregular in density, causing white and grayish patches. The corneal surface usually loses its polish and assumes a dull stippled appearance, due to loss of epithelium. Vessels may appear in the corneal substance, running from margin toward center, and are sometimes numerous enough to cause a bright red re- ilex. Happily, there is very little tendency toward ulceration. This form is tedious, taking months to cure. Suppurative Keratitis. — The inflammatory infiltra- 72 VETERINAKY OPHTHALMOLOGY. Abscess. Onyx. Hypopyon^ Onyx. .. Onyx. tion becomes changed to pus, which pus shows as a yellow opacity in the corneal tissues. The suppuration may be limit- ed, or the entire cornea may be involved. If inclosed by corneal tissue, forms an abscess ; if superficial, an ulcer. Some- times the pus sinks down be- tween the layers, forming an onyx from its resemblance to the lunula of the finger-nail. Often will see hypopyon in the {interior chamber, caused by the pus settling to its bottom. These two conditions may co- exist. Vascularity may attend the suppuration, and with acute symptoms, or there may be very little pain and vascularity, which latter form is very dangerous from death of tissue and sloughing. Abscesses may be absorbed or burst open, or pus may undergo fatty or chalky degeneration, leaving dense opacities. An ulcer may be an opened abscess. But, remember, superficial ulcers may occur without a primary abscess. Ulcers are of variable size, shape and depth, and are dangerous according to their location. The crescentic marginal is exceedingly dangerous from its tendency to encircle the cornea and thus deprive the central cornea of nutri- Fig. 35. YETEEIlsrARY OPHTHALMOLOGY. 73 tion. If an ulcer extend deep enough to reach the membrane of Descemet, it may bulge forward through the ulcer like a vesicle, and thus form a hernia of the cornea or heratocele^ and is usually followed by per- foration. Larger ulcers generally lead to staphyloma. When perforation does occur, there is escape of the aqueous and a carrying forward of the iris and lens. If the iris becomes fast into the Avound, it forms an anterior synechia. If perforation is lai'ge enough, the iris may ijrotrxide^ becoming adherent around the edges, leaving synechia. Sometimes, after healing of the ulcer, there will be re-accumulation of aqueous and tearing loose of the adhesions through the action of the pupillary muscles, the iris then assuming its free- dom, floating in the aqueous. As before mentioned, the lens may also be carried forward against the per- foration, and if it return to its position we may see some matter deposited on its anterior capsule, thus constituting anterior capsular cataract. Remember that adhesions sometimes formed may never be broken, and the anterior chamber may be never re-established. If the aperture, resulting from ulcer and sloughing, be extensive enough to allow of escape of all the contents of the eye, atrophy of the globe will result. The rule in healing of ulcers is that some trace be left, from a slight cloud to a dense opacity, and are variously termed, according to degree — nubecula^ a mist ; nebula^ a cloud ; macula^ a spot. And 74 VETERINARY OPHTHALMOLOGY. often a cloudiness which will be prominent during' convalescence will clear up to a very satisfactory de- gree. But the reverse may obtain. During the heal- ing process vessels may be seen traversing the cornea, but this is physiological and necessary to absorption. Suppurative inflammation may result from many and identical causes with other forms, and is the dread of operators. Bruised and lacerated wounds are also apt to give rise to suppuration. Cases of severe conjunc- tivitis sometimes result so. Treatment includes the ordinary remedies for kera- titis, remembering to avoid all irritants. Even large hypopyon are absorbed, and it is very seldom necessary to evacuate. Paracentesis may be frequently repeated in cases of increased tension. Hot fomentations are often useful, especially in asthenic cases, where there is danger of death of tissue. In deej) ulcers it is better to perform paracentesis through their base than to permit spontaneous perforation. In ulcers that are stqyerjicial and indolent, Scemisches operation is indi- cated and performed as follows : Introduce (after cocaine) a spring speculum ; grasp the conjunctiva opposite point of counter puncture with fixation forceps, (fig. 37) enter the cornea at right angles with a Graefe's knife (fig. 38) thus dividing the minimum amount of tissue ; then turn the knife in- ward, avoiding the iris and lens. Make this primary incision inside the ciliary region, on account of risk VETEKINAFvY OPHTHALMOLOGY. 75 of sympathetic ophthal- mia. This primary incision should be about two ram. from the edge of the ulcer and brought out about the same dis- tance on the other side. The knife then cuts its way out through the bottom of the ulcer. The incision may be kept open by passing a fine probe through it daily, using extreme ascepsis and antisepsis, and the tension kept down until repair begins. Corneal abscess may be treated in a similar manner. You remember my speaking of paracentesis Fig. 36. Fig. 37 of the cornea, — it is performed as follows : Introdce a needle or blade of an iridectomy knife through the cornea near its margin and allow the aqueous to draia =-e G TiPMAMN Jt CO Fgi. 76 VETERINAKY OPHTHALMOLOGY. off sloidy alongside the instrument. The one care in this is to avoid too sudden an escape of the fluid and possible prolapse of the iris. Again, a too sudden diminution of intra-ocular tension is apt to result in shock. Pannus. — A vascular opacity of the cornea, non-in- flammatory. A new growth — neoplasm — the result of a preceding inflammation. The term is applied also to acute and chronic vascular keratitis where the forma- tion of new tissue is still in progress. A part or the entire cornea may be involved. Two forms, remember, I spoke of — tenue, thin, and crassum, thick (or beefy). In extreme degrees the cornea may appear de- cidedly red and fleshy, and this condition may continue for months and years with no change. The rarity is complete cure, for usually a good cure leaves opacities of different degrees. The cornea may become thin and bulge forward. Trachoma is the cause of the majority of cases of pannus, and these cases may present corneal granulations similar to those upon the lids. It may be traumatic from long continued irritation, such as that from foreign particles, inverted cilia, etc. Treatment. — After removing the cause, hasten reso- lution of the opacity, and to this end, if no inflamma- tion be present, irritating powders and unguents are used. Sometimes a too constant application of a remedy wears it out and a cliange becomes necessary. If the entire cornea be involved, the pannus in a high state VETERINAKY OPHTHALMOLOGY. IT of vascularity, and no ulcers existitiff, the Jequirity infusion offers good results. Opacities are frequently the result of corneal inflammations and cicatricial deposits. While they are classified according to de- gree, they are practically divided into superficial and deep, the former affecting the epithelial layer, the latter the parenchyma. A faint superficial opacity is Kg. 89. Fig. 4a called nebula (L. fog), a thick dense one leucoma (Gr. white). A cicatrix combined with prolapse and adhesion of the iris is called leucoma adherans. May see white, chalky deposits, which may be the result of an application of lead lotion where ulceration was pre- sent in the corneal tissues. Many opacities disappear spontaneously in the young and robust. As a rule the more recent and superficial the opacity the better the 78 VETERINARY OPHTHALMOLOGY. chance for removal. The application of ^/leZy powdered calomel will assist absorption by exciting hypersemia and increased tissue change. Deposits of lead may in some cases be scraped away, and the ulcer which results may be filled up with transparent tissue. Cicatricial Staphyloma is generally the result of ulceration, for the floor of an ulcer, being very thin, is therefore very apt to yield to the intra-ocular pressure and bulge. In the process of healing the bulged portion is apt to be covered with cicatricial tissue, and a staphyloma is left, bluish-white in appearance. Remember the leucoma adherans, which may be a complication. Kerato-conxis. — Conical cornea is a cornea cone- shaped. It is a protrusion of the cornea, and its cause is not very well understood. Usually congenital, but vway appear after inflammations. Fistula of the cornea may be the result of a perfora- tion, ulcer or wound. Difficult of cure, indeed. Contin- ual irritation from the constant dribbling of aqueous. Pacqnelin's cautery, carefully cauterizing the edges of the fistula, or a delicate probe dipped in carbolic acid and lightly touched to the opening. Atropine, etc. A compress bandage, enjoining rest, from quiet and gentle pressure. CHAPTER VIII. THE SCLERA. The Sclera is a tough, dense, fibrous structure, con- tinuous with the cornea. Is a little elastic. Possesses blood vessels, in which it differs from the cornea. Its fibrillse are gathered into bundles and cross each other indiscriminately. Lymph canals ramify through these. The cells are fixed, wandering and pigment. Loose connective tissue covers the sclera in front, and is called episcleral, and this in turn is covered by the conjunctiva. The sclera is pierced at the inner side of the axis by the optic nerve. This entrance is also heloxo the exact center. This place of entrance is sieve- like and is called the Icnnina cribrosa, in the center of which is a larger opening, the porus ojyticus, through which passes the arteria centralis. Surrounding the optic nerve the sclera is perforated by vessels and nerves called posterior or short ciliary, which go to the choroid, ciliary body and iris. In front it is pierced by the anterior ciliary vessels. In front the sclera presents an elliptical opening, whose greatest diameter is transverse and whose border is bevelled on the inner side (remember the bevelling of the cornea), and fits 80 VETERINAEY OPHTHALMOLOGY. Fig. 41. VETERINARY OPHTHALMOLOGY. 81 nicely over the corneal circumference. The sclera is thickest around the optic nerve entrance, grows thinner at the equatorial region and thicker again anteriorly. The existence of nerves in the sclera is denied by some. Episcleritus appears as a swelling near the cornea, dusky red in color and most frequently seen over the insertion of the rectus externus muscle. Gives no evidence of tendency to ulceration or suppuration and looks like a phlyctenule. Irritation and tenderness. Rebellious to treatment. Met with in those of rheu- matic tendencies principally, and therefore constitu- tional remedies are the most valuable, (i.e., remedies for rheumatism), and, locally, atropine, and pilocarpin hypodermically administered. Staphlyoma of the Sclerotic. — Before describing this form Avill mention AV/c/vV/.s-, which appears as a general faint pinkish tinge, due to injection of superficial vessels of the sclera. In its later and severer stages this becomes more bluish. If seen early it is hard to distinguish between it, iritis, and conjunctivitis, but the aqueous is clear and no adhesions are present, and that throws out iritis ; and having no secretion, there can be no conjunctivitis. This is another rheumatic accompani- ment, and De Wecker of Paris says in the human being it accompanies the articular rheumatism by preference. Now this inflammation of the sclera, from \veakening €Uid consequent thinning, may lead to staphyloma, and 82 VETERLNAEY OPHTHALMOLOGY. Fig. 42. Anterior portion and ciliary region of the eye. C, cornea ; c S, Schlemm's canal ; O s, ora serrata ; 1 p, pectinated ligament ; e F, Fontana's space ; T, tendinous ring ; m, meridional fibers r, radiating fibers ; ; c, circular fibers of the ciliary muscle ; Z, zone of Zinn. The full lines indicate the crystalline lens, iris, and ciliary body in a state of rest, the dotted. Jines show the same in a state of accommodation. YETERTNAEY OPHTHALMOLOGY. 83 «o here we are. It may be complete or partial. Again, it maybe anterior, between the cornea and the equator or posterior, around the optic nerve. Anterior staphly- loma has a dirty bluish color from the choroid shininfj through, and is of variable size, sometimes, indeed, in- volving tlie whole front of the eye. Where the tumor is small, paracentesis with pressure may check further progress. If verj'- extensive it may be necessary to enucleate the eye. When the bulging extends all around the sclera is called annular staphyloma^ and when complete may protrude so far as to be called hvphthalmus. Injuries of the Sclera. — ^Dangerous, as they com- plicate adjoining tissues and as they permit contents of tlie eye to escape. Small wounds may heal re.adily. Clearly cut, may be united by a fine suture ; 2C[v^ protrudiiuj choroid or vitreous must he cut off with scissors first. Patient kept quiet, and ice compresses employed. If the wound is extensive and in the ciliary region, enucleate and thus avoid sympathetic trouble. CHAPTER IX. THE IRIS. Iris. — The Iris forms in the interior of the eye, in front of the crystalline lens, a veritable diaphragm, with a cen- tral opening — the pupil. Is a beautifully colored and contractile membrane. It is attached at its periphery to the sclera tlirough the fibers of the li (j amentum lycc- tinatum. The shape of the iris is elliptical. It rests (the pupillary margin) posteriorly, on the lens cap- sule. Its anterior surface is free. The iris is con- tinuous with the ciliary body and choroid, and together these constitute the uveal tract, upon which the aqueous humor, the lens and vitreous, depend for nourishment. The iris divides the space between the cornea and the anterior face of the lens and internal extremities of the ciliary processes into two compartments of unequal size — the anterior being the larger and the posterior having only a virtual ex- istence, as the iris rests upon the lens capsule. Both the anterior and posterior chambers contain the aqueous, humor in which the iris floats free. The anterior surface of the iris is lined with a layer of epithelial cells> which are continuous with those on the posterior sur- 84 VETERINARY OPHTHALMOLOGY. 85 face of the cornea. On the back of the iris is a thicker layer containing i:»igment, wliich is continuous with that of the ciliary body and choroid. Xow, this layer of pigment, the tcveciy may be frequently seen as small bodies on a pedicle or stem in the pupillary aperture. Indeed, they may pass through and show in the anterior chamber. Called soot-balls (corpora nigra). More often seen at the upper (pupillary) border. In color they are brownish- black. Unstriped muscle fiber is the predominating constituent of the iris, contained in a stroma of connective tissue, which also contains the vessels,nerves, lymph spaces and cells. Around the pupil some certain fibers are ar- ^ ^ ranged circularly. This is the sj^hincter jmjnlhv, and the dilator ai the pupil is formed of radiating fibers. The peculiar disposition or juncture of these two sets of fibers is that they join each other near the pupil in curves, as I here depict. The sphincter governed l)y the third pair, the dilator by the sympathetic. The iris has three dift'erent classes of nerves sent to it from the ciliary ganglion, which ganglion has three roots — sensitive, motor and sympa- thetic. The twigs which emanate from this ganglion pass to the sclera, surrounding the optic nerve. These are named the short ciliary. The two long posterior #0 86 VETERINARY OPHTHALMOLOGT. ciliary arteries form the circulus iridis major by unit- ing with the branches of the anterior ciliary arteries. From these we have branches which form another ring, the circulus iridis minor, formed by anasto- mosing. The major is formed at the ciliary region. The minor gives off capillaries, which in turn become veins, and, the circulation being established, is re- turned in the same manner as above described. The Txissc^ ^ C I Fig. 44 iris regulates the amount of light admitted to the eye's interior, and by excluding peripheral rays ad- mits of acute vision. Iritis. — Inflammation of the iris is the result of in- juries, cold, rheumatics, extension of inflammation from other parts, etc. Three principal divisions: (1) plastic, (2) purulent, and (3) serous, but a description of one YETERIXARY OPHTHALMOLOGY. 87 general case will suflBce for the general practi- tioner. With the appear- ance of inflammation, and its symptoms, will have an exudate showing at the margin of the pupil. This may go on to such a degree that the aqueous shows decided ' ^'^- ^^' turbidity, iris becomes discolored and sluggish in its movements and much swollen. Kow, this exudate I spoke of, in some forms especially, is sticky, adherent Fig. 46. in its nature, and is the cause of the decided adhesions between the lens capsule and the iris {synechia). This condition may be readily broken up, but if the exudate is of an organized character, i.e., vascular, fibrous, etc., then the adhesions are correspondingly firm. 88 VETERINARY OPHTHALMOLOGY. Under symptoms^ will find photophobia and lachry- niation, frontal pains of a lancinating nature, which are alioays aggravated at night, the degree of pain being some indication of the severity of the case. The lids will be involved to some degree, usually but slightly, however. Careful examination will re- veal a dull, rusty appearing iris, with often turbidity of the aqueous. The iris from infiltration will re- spond to light in a sluggish manner. There Avill be conjunctival and sub-con jnnctival injection, which is represented by irregularly scattered vessels, which may be moved with the conjunctiva by rubbing on the lower lid, remember, and these vessels may be so en- larged and engorged as to present chemosis. The point wnll be the rosy zone of vessels surrounding the cornea, of a delicate pink — not decidedly red, but a pretty deli- cate pink. The lines radiate in a mathematical manner, i.e., with regularity and precision. They are not affected by movement of the lower lid with the finger as are the conjunctival vessels. The degree of this zone-like injection is a criterion as to the severity of the attack. Adhesions will be noticed, and may be slight or very pronounced, from a slight synechia to complete occlusion of the pupil. If they are not seen or easily diagnosed, the instillation of atropine will discover any, no matter the degree, by irregularities of the pupil. (See Fig. 46.) Not wise to expect resolution this side of six weeks. Maybe met within one or both VETERINARY OPHTHALMOLOGY. 89 eyes. The one condition, remember, which will cause a doubtful prognosis is si/nec/na, otherwise, with a reasonably robust patient, the prognosis is good. There is a special form of iritis called purulent, and ^'^" '^'' its most prevalent cause is trauma. Follows opera- tions on the eye. This form is accompanied by the formation of pus usually, and which inay be in such degree as to collect at the bottom of the anterior chamber, forming hypopyon. This may run on to panophthalmitis or general suppuration of the eye. Treatment. — Assure yourself that no exciting cause remains in the eye. Then atro2nne till full mydriasis is secured. If 1% be not strong enough, use stronger and stronger solutions until the effect is accomplished, even to the crude drug. Then maintain it by a weaker solu- tion. The patient must be kept quiet in darkened stall and not overfed. Cold applications are the most recent and successful method of treatment of cases with rheu- matic com plications. But in using very cold applications, watch out for haziness of the cornea, when they must be discontinued (ITelfrich, Schenck). Now, though this seems paradoxical, warmth is a valuable means of treat- ment in some cases, and is especially valuable in re- lieving the pain at night. Let it be d)->/ rather than 90 • VETEEESTAEY OPHTHALMOLOGY. moist heat. If it has been found that a previously existing synechia is an exciting cause, an iridectomy will be in order, and also later, if other treatments are ineffectual. Of course the underlying cause must be cared for, whatever it may be- Fig.48. Fig. 49. Tumors. — Not much to be done. Simple and mali- gnant, as met with elsewhere. If of sufficient import to render it necessary, excise them. Avoid, if possible, in excising cysts, rupturing their walls, if of a serous nature, for the serous cyst is simply distended iris tissue, and is translucent in appearance. There is a condition rarely, very rarely, met with, which I merely mention, called Memhrana Piipillaris VETERINARY OPHTHALMOLOGY. 91 Persistans. During gestation the pupil is closed by a membrane, and occasionally some part or all of it remains. Fig. 50. Iridectomy.— (Excision of a portion of the iris ; re- moval of the entire iris is iridavulsion.) Iridectomy Fig. 51. demands a speculum, fixation forceps, an angular or straight keratome, or Grsetfe knife, iris forceps and 92 VETERINARY OPHTHALMOLOGY. iris scissors, and cocaine 4%. Introduce between the lids the speculum. With the fixation forceps grasp the conjunctiva directly opposite the point of incision (on the opposite side of the cornea, un- derstand), and thus control the eyeball. (A full dose of chloral hydrate is good in irritable patients). The keratorae is inserted about a line from the corneo-scleral margin into the cornea, and intro- duce the blade so as to divide as little tissue as pos- Fig.62. sible. When introduced change the direction of the knife so as to avoid touching the iris or lens. With- draw knife slowly so as to avoid too sudden an escape of the aqueous. With curved iris forceps withdraw a portion of the iris, having grasped it at its pupillary edge. Cut it off with the scissors. See that none of the iris remains in the wound. Compress, bandage. Maintain asepsis and antisepsis, and instil \ per VETEKINAKY OPHTHALMOLOGY. 9B cent. sol. Eserine immediately to draw iris away from puncture and tlius prevent prolapse or synechia, etc. Great care is to be taken not to injure the lens or iris. For sliould you hit tlie lens, cataract is apt to ensue, or glaucoma, with its horrible consequences. The cutting of the iris may be followed by a little hemorrhage, which will be absorbed. Be guarded also, in withdrawing the keratome, that a too sudden evacuation of the aqueous does hot occur, as the sudden diminution of intra-ocnlar tension might be followed by hemorrhage into the vitreous, and this is serious. CHAPTER X. THE CILIARY BODY. Ciliary Body. — Between the iris and the ora serrata. (anterior limit of the retina) lies the ciliary body, which consists of the ciliary processes and muscles. It is th& source from which the lens and vitreous derives nourishment largely. Is composed ot two portions — (1) a muscular and (2) a pigmented and vascular portion. Around the crystalline lens there is a wide black circle^ the ciliary processes, forming regular radiating folds, which project by their inner extremities inward. There are about 120 of these folds, composed of connec- tive tissue, which is con- tinuous with that of the iris and pectinate liga- ment; also of blood ves- sels, convoluted, and cov- ered over all by a layer of pigment. From the fur- pjg 54 rows that separate these processes posteriorly we see a hyaline structure ex- tending, that constitutes the zonule of Zinn, which goes 94 VETEEIN AE Y OPHT H AL:M0L0G Y. C. 95 Fig. 53. Ciliary muscle, after Iwanoff ; a, cornea; b, corneal limb; c, sclerotic; d, iris ; e, Fontana's Spaces. 96 VETERINAKY OPHTHALMOLOGY. to the border of the lens and, dividing, goes to each surface, leaving between its separating surfaces a trian- gular space, called the canal of Petit. This pectinate ligament {Ligamentura Fectinatwii) is that portion of connective tissue where the iris is joined to the sclera at the edge of the cornea. The suspensory ligament of the lens is permeable, transfusion from the vitreous to the aqueous taking place. Chauveau says: "The anterior or ciliary zone includes two parts : the ' ciliary circle ' (or ligament) and the ' ciliary body.' The ciliary circle, ligament or muscle {cmnulus alhidus) varies in width from one to two millimetres ; its external face adheres closely to the sclerotic and its internal is confounded with the ciliary body; the posterior border is continuous with the choroid zone near the canal of Fontana (ciliary canal). The anterior border gives attachment to the greater circumference of the iris." This is a portion of Chauveau which I will explain later, for as it now stands it is not over easily grasped. To quote still further : " The ciliary body {corpus ciliare) forms a kind of zone or ring, wider than the ciliary ligament, and consequently overlaps the latter before and behind. It extends on one side on the inner face of the choroid and on tlie other on the posterior face of the iris." The fibers of the ciliary muscle are of the unstriped variety, and in different parts of the muscle they take different directions, the whole combined making a muscle of triangular shape. This is the YETERINAEY OPHTHALMOLOGY. 97 Fig. 55. Insertion of the zone of Zinn upon the crystalline lens, seen from in front. The pigment of the detached ciliary processes has remained adherent to the non-plicated portion (a) of the zone of Zinn. muscle of accommodation. Vessels are the anterior 7 ^8 VETERINARY OPHTHALMOLOGY. and posterior ciliary, which come from the ocular "branch of the ophthalmic, which in tarn comes from the internal carotid. The nerves are from the ciliary, which contain ganglion cells containing sensitive, motor and sympathetic filaments, and these pass to ciliary body, iris and cornea. These nerves, you understand, come from the ophthalmic division of the fifth, and the fifth is peculiar in its origin — to wit., from the floor of the fourth ventricle and side of the pons and the Gasserion Ganglion (this is sensory), and from the floor of the fourth ventricle and side of the pons for its motor root. Contains also sympathetic filaments. The ophthalmic branch enters by the sphenoidal fissure. Cyclitis. — Inflammation of the ciliary body. The ciliary body is seldom involved alone. Usually the con- tiguous parts participate. Is as a rule an extension of iritis ; choroiditis. If the result of operation, or injury, then it may be alone involved . Under tSi/mptoms will have ciliary injection accom- panied by chemosis, pain. The eye will be intolerant of touch, and that is the symptom. The iris will appear rusty. This may go on to inflammation of all parts of the eye — jxinophthahmtis. Prognosis is not good. Treatment — .Hot fomentations, local bleeding, atro- pine, anodynes, etc. If the attack prove rebellious, as is often the case, enucleation, for the safety of the other eye, which, through sympathy, may participate. Injuries are dangerous, principally because of giving origin to VETERINARY OPHTHALMOLOGY. 99 sympathetic ophthalmia. So, if the eye be injured to -a grave degree, enucleation is tlie word. Irido-choroiditis^ Periodic Opldhahnia^ Jflecciirrent Ophthahnia., Moon hlindness^ {Irido-cyditis). — This iiffection is intimately related to certain climates; systems and soils, and shows a strong tendency to re- cur again and again. Usually terminates in blindness from cataract. Its causes may be said to be, primarily, in the soil — on frequently submerged groiinds ; on marshy and clayey grounds ; on coasts. Also wet, damp climates, which produce lymphatic constitutions. Again, rank, watery foods. This affection is usually seen during the dentition and breaking period ; there- fore are apt to see it between two and five or six. Among local causes would be smoke, acrid vapors, dust, etc. No one of these is sufficient to cause this disease. To-day a microbe is the alleged cause, or the product of a microbe. This product may be preserved in the marshy soil. The presence of a definite germ has not "been demonstrated as yet. Heredity is one of the most potent causes we know. This is very positively demonstrated when both parents have suffered. In support of this, w^e know if a mare had borne a number of foals, all sound, and then suft'ered an attack of periodic ophthalmia, the subsequently born would also suffer. The study of atavism presents many interesting facts in these PAPitt^r'i. An''] yet if *,be foals of diseased parents be 100 VETEEINAEY OPHTHALMOLOGY. transferred to high, dry ground they will nearly all escape. In France, the government rejects all unsound stallions and refuses service to any mare that has suffered. Unwholesome food and errors in feed are undoubtedly predisposing causes, for in a given district those fed with judgment will be granted immunity in a large proportion over those badly fed. Intestinal parasites, over-work, debilitating diseases and causes of every kind that weaken the vitality. The symptoms vary according to the severity of the attack. Some present marked exacerbation of temper- ature, and again it may be entirely absent. But there uhmys is evidence of general disorder, lack of vitality. Locally, symptoms are those of internal ophthalmia with the addition of increased tension or hardness of the bulbus. This may be due to effusion into its cavity. The contracted pupil does not expand much in darkness nor even under the action of a mydriatic. Opacity advances over the cornea commencing at the limbus, and may be partial or complete. And so long as it is transparent the aqueous will be seen turbid, with sometimes floculi. The iris will appear rusty and dullish. The lens will be clouded and will observe a greenish-yellow reflection from the eye. From the fifth to the seventh day the floculi precipitates, the lens and iris are more plainly seen, and the commencing ab- sorption may be complete in twelve to fifteen days. The recurrence is the characteristic of the affection. And VETERINARY OPHTHALMOLOGY. 101 it will recur again and again and in the same eye un- til total loss of sight ensues. These attacks may oc- cur at intervals of a month or so, but they show no relation to any particular phase of the moon, as the name would lead one to suppose. These recurrences are determined, more likely, by some periodicity of the system. From five to seven or eight attacks usu- ally suffice in resulting blindness, and then the second eye is liable to attack with the same result. Between the attacks some latent symptoms tell the story, and these symptoms become more marked with each suc- cessive attack. Even after the frst attack there can be seen a bluish ring around the corneal margin, the eye therefore seeming smaller ; and after several attacks it is smaller from atrophy. The upper eyelid, in place of presenting a uniform continuous arch, has about one-third from its inner angle an abrupt bend caused by the contraction of the levator muscle. The pupil is contracted excei^t in advanced cases, where, with an opaque lens, it will be widely opened, dilated. The animal will carry his ears erect and forward to com- pensate for his waning vision. Xow, this is a general picture, but that the attacks vary with different cases must be remembered. The recurrence, however, is characteristic, and all alike lead to cataract and intra- ocular effusion, giving rise to T +, with pressure on the retina and resulting blindness. The prevention of this disease is the great object, and to accomplish this 102 VETERINARY OPHTHALMOLOGY. most desirable end, we must go back to the starting wire and have careful and discriminating breeding, feeding, stabling, etc., ad infinitum. Treatment is unsatisfactory. Some are benefited by colchicum in scruple doses where rheumatic tendencies are evinced, or two-dram doses of salicylate of soda twice daily. If the tension is increased to a marked degree paracentesis or iridectomy has been attended with good results. When convalescing, tonics — Oxide of iron, x 3 ij. Nux vom, gr. x. Sulphate of soda, 3 3. daily. There is an affection of the eye which has been and is the subject of great speculation and discussion : CHAPTER XI. SYMPATHETIC OPHTHALMIA. Sympathetic Ophthalmia. — Supposed to be due to a pre-existing inflammatory condition of tlie other eye. At its inception there is some photophobia, some injection and laclirymation. With the ophthalmoscope will lind opacities floating in the vitreous. Pain in the ciliary region, especially is it painful to touch. The hazi- ness of the aqueous will be from the exudation from the ciliary processes. Occlusion of the pupil is a common accompaniment. Tension will be increased and loss of sight will be complete. The causes which are responsible for many such cases are injury, trauma, especially in the danger zone, i. e., the ciliary region ; an operation for cataract with the incision too far back of the corneo-scleral margin, for instance; previous inflammations, followed by or i-esulting in atrophy, etc. The period of danger, /. e., when one eye may sympathetically suffer from another, is vari- ously estimated at from two weeks to any period. The most frequent period is from one to two months- The method and means of transmission is as yet an open question, and space forbids entering into the many 103 104 VETERINAKY OPHTHALMOLOGY. theories. Prognosis is unfavorable, especially in ani- mals, as the affair is well established and effusion has taken place, by the time we are rendered cognizant of its presence. Treatment. — Enucleate the exciting eye, and if done early enough, the inflammation will be checked. The sympathetic eye must be treated as a case of in- ternal ophthalmia; to wit,, atropine 1 to 120. Hot fomentations, moist or dry, as you choose, etc. CHAPTER XII. THE CHOROID. The Choroid is a thin, dark-colored membrane situated between the sclera and the retina. Extends from corpus cili are to the optic nerve. Made up of vessels, pigment, and some connective tissue. The blood comes from the short posterior ciliary arteries which anastomose with the long posterior and anterior ciliary arteries. The veins begin as capillaries and take on a peculiar form. Kesemble as much as anything else a weeping willow, and these uniting, form the venae vorticose, emptying into tlie ophthalmic vein. The anterior ciliary vein drains the anterior portion. The long and short ciliary nerves form plexuses in the choroid and contain a number of ganglionic cells. Between the retina and choroid there is a layer of pigmented epithelium. The inner face of the choroid is not uniform in color, being perfectly black in the lower part of the eye. This is abruptly terminated at a horizontal line about the eighth or ninth part of an inch above the optic papilla. From this line on the segment of a circle from j*^ to ^% of an inch in height, it shows most brilliant colors; at first 105 106 VETERINAKY OPHTHALMOLOGY. blue, then an azure-blue, afterwards a brownish-blue, and after this the remainder of the eye is occupied by- Fig. 57. an intense black. The bright portion is the tapetum. The Retina lies between the choroid and vitreous. VETERIMAltY OPHTHALMOLOGY. 107 Extends from the optic nerve to the ciliary processes, where it is called the ora serrata. Consists of ten layers. (1) The internal limiting membrane, separates the nerve fiber layer from the vitreous, and the fibers of Miiller terminate in this layer. (2) IVie nerve fiber layer, consists of the axis-cylinder of the optic nerve fibers, which run in a radiating direction to the ora serrata, where they terminate. At the macula lutea these fibers are bent into arches, and this arrangement permits a larger number to reach the yellow spot than if they approached in a radiating direction. (3) The layer of ganglion cells, composed of multipolar cells, each with a nucleus and nucleolus. A nerve fiber en- ters each of these cells, and one or more prolongations extend out into the inner molecular layer. These ganglionic cells are arranged closer around the optic nerve than at the ora serrata. (4) The internal molecu- lar layer, one of the thickest, granulous in appearance. Consists principally of fine fibers from the layer of ganglion cells. (')) T/ie infer/ud granular layer, com.- posed of two kinds of cells with nuclei. The larger are nerve cells, having tico offshoots, one passing into the inner granular layer, anastomosing Avith offslioots of the ganglionic cells, the other out to the external molecular layer and supposed to anastomose with fibers from the layer of rods and cones. The smaller cells of this layer are connected with the fibers of Miiller. (0) The external molecular layer. Very thin and is made up of 108 VETERINAPvY OPHTHALMOLOGY. the fibers just mentioned with some molecular matter. (7) The external granular layer. Composed of both nerve and connective tissue elements. Former consists of bi-polar cells, from which offshoots pass out to the rod and cone layer and inward to the internal granular layer, (8) The external limiting membrane^ formed by the terminal extremities of Miiller's fibers. (9) Tlie layer of rods and cones. The rods commence as fine fibers in the outer molecular layer, pass through the outer granular, and just beneath the external limit- ing membrane begin to increase in size, forming the rod granule, and some distance after passing through, this membrane they taper down into cylindrical-shaped rods which extend outward to the pigment layer. The cones also commence as a cone-shaped swelling in the outer molecular layer, where they are in direct commu- nication with the fibers from the internal granular layer. The cone fiber becomes thinner until, just un- derneath the external limiting membrane, it again swells rapidly and there forms the cone itself, which contains a large oval nucleus and nucleolus. The cones are shorter and thicker than the rods, and are of a bottle-shaped appearance. The rods and cones are arranged perpendicularly to the plane of the retina, and may be divided into an inner and outer part. The inner is thickest and appears granulated ; the outer is broken up into highly refracting lamellae, appearing like superposed discs or piles of coins. (10) The 2>ig- VETERINAIIY OPHTHALMOLOGY, 109 ment layer, is a single layer of hexagonal nucleated cells, the inner surface of which is loaded with pigment ..au..| j-^ •sfcisi^asii^ Fig. 58. Section of Normal Retina X 350.-Eye removed for Sarcoma, Retina de- tached but almost normal.-l, Vitreous ; 2, hypertrophied cells of vitre- ous ; 3, membrana limitans interna ; 4, fibers of Muller (they are slightly hypertrophied)— they are part of the connective tissue frame work ; 5, layer of optic nerve fibers, nuclei more numerous than usual ; 6, layer of ganglion cells, some of them having undergone colloid degeneration ; 7, internal molecular or reticular layer : 8, layer of inner granules ; 9, external molecular reticular layer— in this as in the internal molecular layer the fibers of Miiller are abnormally distinct ; 10, layer of outer granules ; 11 and 13, layers of rods and cones, in which a distinction is made between the body of each element, 11, and the process 12, which is its continuation ; 13, layer of epithelial pigment in polygonal cells.— {Xoyes). granules. The fibers of Muller form the connective 110 VETERINAEY OPHTHALMOLOGY. tissue framework as they traverse the various layers and spread out in its membranes. At the ora serrata all the nerve elements disappear and the connective only continues, forming the zonule of Zinn. The Macula lutea, or yellow spot, is the seat of most acute vision. The macula contains no rods, while the cones are longer and narrower than elsewhere. At the center all the retinal layers are thinned, and this is called VdQ fovea centralis. The retina possesses a particular vascular distribution. The arteria centralis retinae with its vein enters the optic nerve at a short distance from the globe, and xoith it passes into the eye. They traverse the papilla and immediately divide into two branches, one up, the other down. These branches then turn out, but none of its capillaries extend into the fovea.* Now, though the choroid and retina may be in- dependently inflamed, I propose to describe inflam- mation of both under Internal Ophthahnia. Severe blows, punctures, foreign bodies, sudden transition from darkness to brilliancy, glare of snow, cold and dampness, high winds, (front of ferryboats, for instance), rain, exposure when heated, and many general diseases, among which are rheumatism and influenza. Met with during dentition. There are not many external symptoms, unless the cause was * The above description of the retina was taken largely front liforton's excellent work. VETERINARY OPHTHALMOLOGY. Ill external, such as a blow, puncture, etc., in which case the lids and conjunctiva would participate to a marked degree. Otherwise the symptoms would be deep. The anterior edge of the sclerotic where it overlaps the cornea will remain white, when posterior to it will show congestion ; and this is caused by the fact that the arteries (ciliary) penetrate the sclera behind its anterior border. This many times cannot be seen, owing to pigmentation. The opacity of the cornea may be confined to its outer margin. The aqueous will be turbid and will see yellow-white flakes floating in it. These may deposit and form hypopyon. The iris will be dull and rusty, as in iritis. Intense photophobia. Watch out for jldhesions. In taking the tension will find it plus, even to -j- 3. In severe attacks the forma- tion of pus in the choroid (and iris), which escaping sinks to the bottom of the anterior cliamber, form- ing hypopyon, as above stated. In nearly all cases cataract results. Treatmext. — Quiet, rest, darkness. May give a purge, if patient is robust. If any rheumatic ten- dency, colchicum, 3 ss and Sod, salicyl, 3 ss, daily. You will treat the eye much as for conjunctivitis. Astringents — Boric ac. 4% ; Zinc, sulph. one to two grs. to the 3 , and jiever forrjet the instillation of atropine 1%, using an eye dropper. Some advise use of a feather, but that is apt to carry foreign matters with it, so don't. In cases of severe pain, cocaine 4% is 112 VETERINARY OPHTHALMOLOGY. good. Local bleeding and blisters, the bleeding being accomplished by shaving the part desired and apply- ing leeches. A word or two anent the Vitreous humor. It oc- cupies all that portion of the eye behind the lens. Has a def)ression in front called the lenticular fossa or fossa patellaris in which rests the crystalline lens. It (the vitreous) is adherent to the optic nerve and ciliary body and has no other attachments. It is contained in the hyaloid membrane, and this membrane forms the zonule of Zinn, and it is between the layers of the zonule and around the circumference of the lens that we have the canal of Petit. Now through the center of the vitreous may be discovered a canal, the canal of Cloquet, for the hyaloid artery during foetal life. This is sometimes (very rarely) seen after birth, and is then termed Persistent Hyaloid Artery, and it has no attendant vein. The vitreous humor has neither blood vessels nor ner- ves, but it must be classed with organized struc- tures because of the cells it always contains. These cells have no de- F's- 59- finite form, being round, star, spindle, etc. CHAPTER XIII. CRYSTALLINE LENS. Crystalline Lens. — A transparent, biconvex body, solid and inclosed in a membrane which is transparent and called its capsule. According to Chauveau the measurements are vertically j\ of an inch ; trans- versely yV- The posterior face, measuring transversely ■^, is the more convex, for the anterior transverse diameter is but -^\j. The lens is enveloped in its cap- sule but nonadherent to any part of it, and this capsule is of uniform thickness. Is composed of an elastic homogeneous membrane, being lined anteriorly with a layer of cells which give nutrition to the lens. The zonule of Zinn or suspensory ligament supports the lens, maintaining it in its position. This ligament, you will remember, is the continuation of the mem- brana limitans of the retina which passes over the ciliary process to the border of the lens and separ- arately passes to the front and rear of the capsule, thus enveloping it and making a capsule. The canal of Petit, you see, is the space between the dividing sur- faces and the circumference of the lens. Function of this canal is in doubt ; supposed, however, to convey 8 113 114 VETERINARY OPHTHALMOLOGY. nourishment to the lens. The zonule has control over the accommodative changes of the lens. The tissue proper of the lens is composed of concentric layers, and each layer is composed in turn of a single layer of Fig. 60, Eye of calf— third month (Kolliker). pp, lower lid; pa, upper lid; m,. mesoderm not yet differentiated ; c. cornea; mp, membrana papillaris; i, place of iris ; che, chorio-capillaris ; g, vitreous ; p, pigment layer or proximal lamella of the secondary eye vesical; r, its distal lamella, composing the retina. fibers with a cementing substance. These fibers have each an oval nucleus. Now, each fiber runs from the an- terior to the posterior surface in a meridianal manner, the ends meeting at the poles of the lens in such a manner as to form a star-like figure. Taking the lens. VETERINAKY OPHTHALMOLOGY. 115 :as a whole, it is divided into a nucleus and a cortex. A single layer of fibers under the microscope ■will be seen to lie parallel and each measure about ^oVu o^ ^^ inch in thickness. They unite with each other by serrated borders, by dovetailing. The lens acts as any plus lens, bringing light to a focus. Cataract is the ■common result of internal ophthalmia and is an opacity Pig. 61. Fig. 62. of the crystalline caused by interference with its nutrition. Ergotism is a cause, but we don't know how. Clataract may occur at any age. Sometimes congenital. Two principal divisions, hard and soft cataract. There is a peculiar form called mor(/a[/nian, and is a hard nucleus or a fluid cortex, or a cataractous lens floating in a fluid medium. Traumatic cataract is a soft cataract following trauma. The detection of cataract is by oblique illumination. The extraction of the cataract will not improve vision, and as its appear- 116 VETERINARY OPHTHALMOLOGY. ance is not marked, operative interference is not imper- ative. The horse would be a shyer after removal, as the rays of light would not he focused on the retina. Jteclination or depression of the lens into the vitreous has been done, but it is dangerous, the lens being apt ta set up hyalitis, etc. Ectopia Lentis or dislocation of the lens, is generally the result of injury. May be spontaneous and has been congenital, from weakening of the zonule of Zinn. It may also be complete or partial. CHAPTER XIV. THE OPTIC NERVE. The Optic Nerve. — Of this we will have but little to say. The anatomy of the nerve is so well laid clown in Chauveau and the various works on anatomy thab I will proceed at once to an affection called Amaurosis (Ambhjopia). Palsy of the nerve. The term amblyopia is used when there is some impairment of vision for which we can ascribe no cause. Vision is often thus defective where the eye has long been disused — ambly- opia from disuse or ex anopsia. In anaemia subsequent to severe illness or hemorrhages, amemic amblyopia. In lead poisoning. From exposure to prolonged glare, as in snow-blindness. From irritation of the fifth pair, as in neuralgia ; overdosing with quinine. Also tumors and other diseases of the brain implicating the roots of the optic nerve. Injury to the nerve between the brain and eye. Iletinitis. Undue pressure upon the retina from dropsical or inflammatory effusion. Also occurs from overloaded stomach, even from pressure of the gravid uterus. Sywjytoms. — The pupils are dilated widely and do not react to light. A feint to strike does not cause the 117 118 VETERINAEY OPHTHALMOLOGY. Fig. 63. Scheme of the Central Visual Apparatus.— R, Retina, shaded where It l3 Innervated by the left, clear where innervated by the right hemisphere : No, Optic Nerve ; Ch, chiasma ; Too, Tractus Opticus ; CM, Melnerts commissure ; CG, Guddens commissure, b, lateral tract root ; m, median tract root ; Tho, thalamus opticus ; Cgl, corpus geniculatum laterale ; Qa, notes ; Bqa, brachia anterior ; Rd, direct cortical tract root ; Ss, saggital medullary layer of occipital lobe ; Co, cortex (chiefly of the cuneus) ; Lm, median tract.— {Schleife). VETERINARY OPHTHALMOLOGY. 119 horse to swerve. And here a word. In making these feints, be sure you do not cause a current of air to strike the animal which would cause him to start and so possibly deceive. The ears are held erect and move quickly on appreciating any sound. He will also step high. Treatment is useful only when the disease. is symp- tomatic of some removable cause. Should the condi- tion persist after the subsidence of the supposed cause, try blister, (post auricular,) and give 3 ss doses of nux vomica daily. Atrophy of the Optic Nerve. This may be the oc- casion of the condition above described and (fig 64) is to be watched for, especially on passing horses. So it is imperative to know and handle the ophthalmoscope intelligently. The general symptoms are as described under Amaurosis. Tlie ophthalmoscopic symptoms are here the interesting ones. The disk is almost always white — decidedly so — but may be grayish, and the lamina cribrosa may be distinguished. The blood sup- ply is lessened, witli consequent paleness, and the larger vessels will be lessened in caliber. Thus is it very evident that the student must /oioto the appearance of a normal fundus. (See colored plate.) Colored crayons and a blackboard will not convey the required picture, be they ever so happily depicted. The disk will be sharply outlined, and often this outline will be pigmented. If this atrophic condition 120 VETERINARY OPHTHALMOLOGY. succeeds an inflammatory attack, the outlines will be ragged and ill-defined. The duration of a case of atrophy is tedious, very, months and years being Fig 64. "usual time of duration of a case. Occurs at all ages and may be congenital. Prognosis is unfavorable. Treatment. — Little or none. Strychnia may be used, iypodermically, about the temple. CHAPTER XV. GLAUCOMA. Glaucoma. — Xortoii defines glaucoma as "an excess of pressure "within the eye, plus the causes of and consequences of that excess." That place where the tissue of the iris, the cellular stroma of the ciliary- body and the posterior and external portions of the cornea and sclera intersect, is known as the iritic angle (see fig. 53). This juncture combines to make a tissue of a fenestrated nature. Tiiese fenestra or openings are the Fontana spaces. The meshes of this tissue (just imagine a coarsely meshed fisher's net) merge into Descemet's membrane and form the liga- ijiention pectinaium hidis. In the sclerotic is formed, by the same means, the canal of Schlemm (see fig. 42), and all of these spaces, etc., are connecting and are of the lymphatics. The caiial of Schlemm communicates with the sclerotic veins, and thus the connection between the anterior chamber and the circulation is established. Blood is never found in these spaces physiologically. The zonule of Zinn, which you remember extends from the ciliary processes, (posterior surface) to the 121 122 VETERINARY OPHTHALMOLOGY. lens, is a readily transfusible membrane. The pres- sure in the aqueous and vitreous are equal, and this equilibrium must be maintained to have a normal eye. Tiie slightest excess will destroy its function in cor- responding degree. This equilibrium is rendered stable by due secretion and excretion of the fluids. The intra-ocular fluids flow from the blood stream. The ciliary body supplies the fluid to the vitreous, aqueous and lens. Most of the secretion passes directly to the aqueous by means of the pupil and filtra- tion angle. A very much smaller portion passes back- ward and out through the papilla. The most impor- tant change v/hich takes place in glaucoma will be found at the iritic angle, affecting the vessels compos- ing or entering into Schlemm's canal. These are inflammatory, and the iris becomes adherent to the cornea and closes up Fontana spaces partially or wholly, thus hindering the excretion of the fluids, and so aug- ments the condition. The fibers of the optic nerve become inflamed, and atrophy, in the later stages. There may be fluidity and detachment of the vitreous and cataract of the lens. Symptoms. — Take the tension, gently palpating with finger tips, using both hands, and it may be any thing, i. e., -f or — . Palpate through the sclera back of the cornea. Cases will be met with where the tension will be stony in its degree of hard- ness. Haziness of the cornea is usually present, and VETERINARY OPHTHALMOLOGY. 123 the cornea will also present anaesthesia. Dilation and inactivity of the pupil is a constant symptom. The word glaucoma means green, and so we do get a greenish reflex in glaucomatous eyes. The pain may be slight or severe, and may have general symptoms of fever, etc. Swelling of the lids, chemosis and protru- sion (exopthalmus) are all due to infiltration from pres- sure. Glaucoma comes in relays, /. ^., have a prodromal stage of a variable duration, weeks, months ; and then a sudden attack, lasting from a few hours to days, and then the eye returns to normal or nearly so. These attacks return, and the intervals become shorter and shorter, and finally, chronic or a.bsolute glaucoma. Some cases go right from an acute to absolute with no re- batement of symptoms. Glaucoma tends to absolute blindness. Any condition causing vascular turges- cence may cause gout, rheumatism, fever. The use of atropine has caused it. Prognosis is always bad. I had the pleasure last year of showing the class a caso of Glaucoma secimdarium in one of the clinics. One of the patients from the Broadway car stables was pointed out to me as having an interesting eye, and so it was. Secundarium means increased intra-ocular tension, consequent to some other disease. This case presented total occlusion of the pupil, the pupil being fast completely around to the lens capsule. (See Fig. 47.) The eye was buphthalmic and hydrojyhthalmic. The whole globe was enlarged, and the cornea especially was 124 VETEEINAEY OPHTHALMOLOGY. distended, resembling, indeed, a soap-bubble. The lens might have been of ground glass for all its transpar- ency. Nothing could be done. I have said Atropine has caused. Since then, in- vestigations have led to the use of Scopolamine Hydro- bromate, which we have reason to believe does not in- crease intraocular tension. Therefore, use in place of Atropine (in strength 1 to 200) wherever have cause to suspect «;iy t?icrease in tension. Another point. In making up collyria, use Trikresol 1 to the 1000 (in place of distilled water only as this will not decompose and is harmless to the eyes). Teeatment. — The only medicinal remedy is Eserine Sulph. ^% every couple of hours, and must be used early. In veterinary practice the opportunity to use it does not occur, as the condition is well advanced by the time it is diagnosed. The eserine, you know, will ontract the pupil and thus tend to freeing the iritic angle. Also constricts the vascular system, diminish- ing secretion. Dovbt use atropine. Iridectomy^ introduced in '57 by Von Graefe, is the operation for glaucoma. The incision should be in the sclera, and allow the aqueous to drain away gradually^ and be sure that no remnants of the iris remain in the wound. The eye is not exempt from parasites, and we meet with Acari (mites), and nothing need be further said, as you all know of them and have suffered from their getting in the eye. TETEEINAEY OPHTHALMOLOGY. 125 Filaria lachrymalis.— A white worm, about an inch in length, found in the lachrymal duct and under side of the eyelid and meinbrana nictatans. Their presence sets up a conjunctivitis spoken of as a vermi?ious con junctivitis. Remove and treat. Filaria papulosa. A silvery delicate worm, about two inches long. Seen in the aqueous and is very active. This was Barnum's famous " Snake in the Eye." Sets up inflammation and has to be removed. Best to make incision in upper half of cornea near the scleral border. Then treat the inflammation. The Echinococciis, the larval state of the tape- worm of the dog has been found in the eye. Cysticercus has its origin between the choroid and the retina, and causes detachment of the latter, finally perforates it and enters the vitreous, and entering the vitreous, sets up an irido-cyclitis and goes on to de- struction of the eye. Pentastoma Taenioides has been found by Stitten ia the horse's eye, but this case stands alone. CHAPTER XVII. ENEUCLEATION. Eneucleation. — Instruments necessary will be curved blunt-pointed scissors, speculum, fixation for- ceps and a strabismus hook. The administration of cUoral hydrate in full doses, and also cocaine 4 per cent., is necessary to this ox^eration. Separate at the corneal margin the conjunctiva from the globe, going completely around, of course. Then divide the attachment of the superior straight, after catching it on the strabismus hook. Have an assistant hold the wound open with this hook, while you take another and insert it under the insertion of the internal straight, and so proceed with the balance of the muscles. Some divide the obliques previous to the optic nerve, and others, the reverse — protruding the eye by pressure — dividing the obliques and then the nerve. Do whichever method comes the more natural to you, and as the exigencies of the case pre- sent. With the scissors closed, push, probe and sepa- rate your way back, until the nerve is reached on the inner side, and, with one cut, divide the nerve. Will have an immediate flow of blood, which is easily con- trolled by pressure. This operation is followed, as. 12G VETERINARY OPHTHALMOLOGY. may be easily imagined, by considerable reaction, some- times fatal. There is a method ascribed to Liebold which is followed by less reaction and is called Exen- 127 Fig. GO. Fig. 68, teration, and consists in opening the eye by excising the cornea at its limbus and removing the entire con- tents. When these cases have been fatal, has been by 128 VETERINARY OPHTHALMOLOGY. meningitis mostly. Still, with ascepsis and antisepsis closely observed, there need be no hesitation in per- forming this operation. A word or two anent the Ophthalmoscope and its use. This instrument was the result of long and care- ful investigation by Professor 11. Ilelmholtz of Berlin. Was introduced to the scientific world in 1851. The scope, as it exists to-day, consists of a mirror, either plane or concave, with a perforation called the sight hole. Also generally there is an object lens. The mirror is the essential. Usually we use a lamp for light, and have it held behind and to one side of the eye Ave wish to examine. The examiner should keep both eyes open, for the same reason that a sailor will keep both open when using the telescope, and what- ever may be seen by the other eye must be disregarded. The first thing noticed will be a ref? reflex, where before the introduction of the beam of light all seemed black. Having succeeded this much,' the student will try and make up his mind finally that this particular eye has no disc, hut it is there, and that is the objective point. Find the disc. Just when one decides to " let go" and postpone the search, like a moon in a brilliant sky, the disc will sail into sight, and as quickly sail out of view. However, we have demonstrated to our own satisfaction that it is there, and that gives one the needed stimulus to go on and patiently endure disappointment after disappointment, until, as always, success crowns VETERINARY OPHTHALMOLOGY. 129 our efforts and we are astonished and pleased with our ability to locate the disc and study its condition at will. We cannot tell our patients to look upward, down- Fig. 69. ward, to the right, to the left, and thus bring into the field each and all portions of the fundus. Therefore ine do the see-sawing, and, having gotten the focus, 9 130 VETEEINARY OPHTHALMOLOGY. slide your head, (and with it your eye) vnth the scope in position, to tlie right and left, upward and down- ward. There are two methods of examining the fundus — direct and indirect. In the direct method, the image (tliat which we see and appreciate, at the bottom or fundus of the eye, is the image), will be erect, i. e., it will have suffered no inversion, as is the case when the indirect method is employed, for there we interpose a biconvex lens between the eye examined and our own, thus inverting the image This I demonstrated early in the session upon the blackboard diagrammatically. Now, if you, for experi- ment, will take a piece of card- board and drive a pencil through it, you will tind on looking through the result- ing hole that the nearer your oicn eye you bring the card the larger will be the field of vision. Yes? So with the eye of the subject, for the pupil represents the hole in the cardboard. But there is a bar here which can be overcome only by experienced pilots. The observer must put his own eye in a condition equivalent to his looking at an object in the distance — twenty feet — i.e., his eye, to see the fundus (the ac- commodation of the observed eye being suspended, at rest) must be in a condition to receive parallel rays. Fortunately, the horse under examination being in a semi-darkened room, relaxes his accommodation, and thus one factor is overcome. This is to be accom- plished only by 2^f'cictice, and like all good things is VETERINARY OPHTHALMOLOGY. 131 gained only by patient application. The observer's eye must be normal, i.e., neither hyperopic, myopic or astigmatic, and if such conditions do exist they must be corrected by a proper glass. The indirect method^ {the inverted imar/e.) To use this, the examiner holds in front of the observed eye a biconvex lens of 2.} or 3^, inch focus, and does not bring the scope nearer than one foot, and he may draw gradually back until the proper view is obtained, the top of the scope # cu b c Fig. ri. touching the eyebrow. This biconvex lens condenses the light v.iiich the mirror throws to the eye, and of necessity (light returning in the same direction in Which it came) passes through the lens, becoming- inverted and forming an image hetireen the lens and mirror, in the air, and is thus an aerial image. An im- portant aid to diagnosis is the 2J inch lens which accompanies the ophthalmoscope, and which we use in tlie indirect method, and also for oblique illumina- tion. In oldeu times, before oblique illumination, the catoptric test was used to detect cataract, etc., in the lens, but where it was most desir- 132 VETERINARY OPHTHALMOLOGY. able, i.e., in the very obscure and slight cases, it was of little use. It is still useful in determining the presence or absence of the lens, and depends upon the fact that the surfaces of the cornea and lens reflect images and consists of the following maneuvres : Hold a candle, lighted, '.efore an eye in a darkened room, and you will observe three distinct images — the anterior, bright, erect and distinct from the anterior surface of the cor)iea ; an intermediate, slight, smaller, inverted, and fairly dis- tinct from the lens' posterior capsule, which is con- cave ; and a posterior, indistinct and erect from the surface of the len£ anterior capsule. To return to oblique illumination, and this is of extreme applica- bility. While being very easy, the veriest novice hav- ing it at his conmiand, it is decidedly thorough, one being enabled by its mediation to discern the slightest opacities and strise of incipient cataract, etc. For this test, need but a 2J inch lens and a candle flame. To be thorough, the use of cocaine, atropine, or scopo- lamine is necessary. Have the candle placed on one side of the head and concentrate its rays by means of the lens so as to focus upon the eye, and then the cornea, the pupil, the iris and the lens may be very thoroughly studied. For the examination of the anterior parts and chamber, the lens is suflBcient, but there it ends and the ophthalmoscope comes into play. If we take a small box and punch a hole in the top, through which we send a pencil of light by means YETERINArvY OPHTHALMOLOGY. 133 of our 2i inch lens, we illuminate the interior, and can study its every part. "Well, then, why not the same with the eye ? The eyeball is not a box simply. It contains a lens, and that is why. If you throw a pencil of light into the eye it will be brought to a focus by the lens. That is not the case in a simple box. Tlie light has to come back again and emerge from the eye. So if the lens (biconvex) brings the entering rays to a focus, it does the same for those emerging. (See figs. G and 7.) But the entering rays were parallel and brought to a focus through the mediation of the lens, whereas the emerging rays, coming from a focus, were rendered parallel. Let us go a little furtlier. Suppose divergent rays be the case, as they will pass to the lens and on returning will be converged and made to meet at a focus in front of the lens. As the rays primarily were not parallel, but divergent, the focus at which they meet after passing through the lens will not be at the same distance, as you see. They will be further than the focus for parallel rays. If one of tlie foci be brought nearer the lens the otlier will be further off and are called con- jugate foci. Xow, please notice that although con- jugate they maintain a certain distance between each other, for as you approach one foci the other recedes. So, all rays emanating from the eye take a direction toward the conjugate focus, and if one attempts using this ray to see the fundus he must necessarily bring 134 VETERINARY OPHTHALMOLOGY. his eye into their line. Tlien what happens? The line occupied by these rays is the same that was taken by the entering rays, and if no rays enter the eye, none will emerge. And when you try to intercept the rays coming /rom the eye so as to make use of them in view- ing the fundus, you get in the path of the lines of light which enter and of course your head intercepts them. Consequently, having cut off the source of light, the result is darkness. For example, a candle a couple of feet from the eyes will give divergent rays, which will enter the eye, be refracted and focus on the retina, forming an image of the candle-flame. The rays will undergo reflection, and being reflected back through the lens, will be again refracted, and you will find at the candle-flame an image of the fundus, and at the candle-flame is one of the conjugate foci. Of course, if you interpose your head between the eye and the candle, the rays emanating from the candle will be cut ofl: and, in place of the observed eye being illuminated it will be in a shadow of your own head. If you try to look from the other side of the flame, i. e., having the flame between you and the patient's eye, you will be dazzled by the flame, as it radiates light in all directions though in straight lines. And there the matter stood until, in 1851, Helmholtz, after careful study evolved the Ophthalmoscope. "What was wanted was a some- thing which would allow an observer to bring his head into his own light. This the mirror, which is a VETERINARY OPHTHALMOLOGY. 135 part of the ophthalmoscope, does, being a mirror pierced by a hole for observation. An ophthalmoscope consists principally of two parts— a mirror and a lens, and the mirror is the essential part, everything else being accessory. " Find out the cause of this effect. Or rather say the cause of this defect, For this effect defective comes by cause." Hamlet. FINIS. INDEX OF ILLUSTRATIONS. PACE. Action of ocular muscles 47 Apparatus, lachrymal 38 Agnew's canaliculus knife 41 Anterior staphyloma 69, 77 Abscess, corneal 73 Accommodation 83 Angle of incidence 8,9 Angle of reflection 8, 9 Anterior portion and ciliary region 13, 82 Angular keratoma 90 Artery, persistent hyaloid 113 Body, ciliary 82, 94 Cowman's probes 43 Corneal cells 66 Corneal abscess 73 Clamp forceps 37 Canals, hygrophthalmic 38 Canaiiculi 38 Canaliculus knife, Agnew's 41 Ciliary body 82, 94 Cornea 83 Canal, Schlemm's 83 Circular fibers of ciliary muscle 8.?- Ciliary muscle, circular fibers of 83 Crystalline lens 82, 115 137 138 INDEX OF ILLUSTRATIONS. PAGE. Cells, corneal 66 Cells, pigment, of iris 85 Corpus, eiliare 94 Ciliary processes 94 Ciliaiy muscle 95 Cornea 95 Colored plate .Frontispiece Choroid 104 Ciliary region 13, 83 Cell, pigment, of retina 14 CJavity, orbital 19 Cartilages, tarsal 27 Coat, choroid - 104 Cells, ganglion 109 Central visual apparatus 118 Catoptric test 131 Candle test 131 Decomposition of light 12 Dilator pupillae 86 Duct, nasal 38 Disc 120 Eye, third month 114 External molecular layer of retina 109 Eye of calf at third month 114 Embryological eye 114 Enucleation scissors 127 Eyelid, saggital section of upper 25 Eye, muscles of 46 Eye, general scheme of (tailpiece) 80 Formation of image 4 Foci of rays 10, 11 Fontana's spaces 83 INDEX OF ILLUSTRATIONS. 139 PAGE. Fibers, meridianal, of ciliary muscle 82 Fibei*s, radiating, of ciliary muscle 82 Forceps, fixatiou 75, 90, 127 Fontana's spaces 95 Forceps, iris 90 Fibers, circular, of ciliary muscle 82 Fibers of Muller 109 Fixation forceps 75, 90, 127 Fixation speculum 127 Forceps, trachoma 59 Forceps, clamp 37 Gland, lachrymal 38 General scheme of the eye 80 Ganglion cells 109 Hyaloid artery, persistans 112 Hook, strabismus 127 Hypopyon 72 Hygropthalinic canals or lachrymal ducts 38 Image, inverted 17 Iris 82, 95 Iris, pigment cells of So Iritis 87 Iris forceps 00 Iris scissors 91, 92 Iridectomy 91 Insertion of zonule of Zinn 97 Inverted image 17 Internal molecular layer of retina 109 Internal granular layer of retina 109 Jaeger's keratorae 90 Jones-Wharton, operation of 35 Knife, Agnew'scaiinliculiis 41 140 INDEX OF ILLUSTRATIONS. Knife, Stilling's 43 Keratitis, phlyctenular 71 Knife, Saemische's 75 Keratome 90 Lachrymal ducts or hygrophthalmic canals 38 Lid, saggital section of upper 25 Ligament, pectinated 82 Layers of retina 106 Layer of optic nerve fibers 109 Layer of rods and cones 109 Lens, crystalline 82, 115 Loring's ophthalmoscope 129 Lid, vertical section of upper 34 Lachrymal apparatus 88 Lachrymal gland 38 Lachrymal sac 38 Muscles of eye 46 Muscles, scheme of action of ocular 47 MuUer, fibers of 109 Muscle of accommodation 82 Meridianal fibers of ciliary muscle 82 Muscle, ciliary 95 Nerve, optic 118 Normal fundus of eye Frontispiece Normal retina, section of 109 Nasal duct 38 Ocular muscles, scheme of action 47 Onyx : 72 Operation, Wharton-Jones 35 Optic nerve fibers, layer of 109 Outer granular layer of retina 109 Optic nerve 118 INDEX OF ILLUSTRATIONS. 141 PAGF. Of-tic disc 1'20 Ophthalmoscope -129 Ora serrata 83 Occlusion of pupil 85* Orbital cavity 19 Operation for ptosis 33 Pencil of rays of light 9 Prismatic spectrum 12 Pigment cell of retina 14 Ptosis, operation for 32 Pectinated ligament 82 Pigment cells of iris 85 Pupil, spliincter of 86 Posterior synechia 89 Pupil, occlusion of 89 Pupil, dilator of 86 Processes, ciliary 94 Pigment, epithelial of retina 109 Persistent hyaloid artery 112 Pterygium 62 Phlyctenular keratitis 71 Puncta 38 Probes, Bowman's 43 Retina, reticular layer of 109 Retina 106 Retina, section of normal 109 Reticular layer of retina 109 Ring, tendinous, of ciliary muscle 82 Retina, internal molecular layer 109 Radiating fibers of ciliary muscle 82 Retina, inner granular layer 109 Refracted ray of light 7, 9 142 INDEX OF ILLUSTRATIONS. PAGK. Retina, external molecular layer ll'J Region, ciliary 13, 8'3 Retina, pigment ceil of 14 Retina, outer granular layer 109 Rods and cone layer .109 Retinal layer of epithelial pigment 109 Scheme of the central visual apparatus 118 Scissors, Enucleation 127 Schleram's canal 83 Section, sagittal, of upper lid 25 Space, Fontana's 82, 95 Strabismus hook -127 Section of normal retina 109 Synechia 87 Speculum, fixation 127 Serrata, ora 82 Sphincter pupillae 86 Synechia, posterior 89 Scissors, iris 90 Spaces, Fontana's 82, 95 Scheme of accommodation 6 Seven primary colors 12 Spectrum, prismatic 12 Sagittal section of upper lid 25 Section, vertical of upper lid 34 Symblepharon 36 Sac, lachrymal 38 Stilling's knife 43 Scheme of action of ocular muscles 47 Staphyloma, anterior 69, 77 Spring speculum '^5 Saemische's knife -75 IXDEX OF ILLUSTRATIONS. 143 PAGE. Speculum, spring 75 Scheme, general of the eye 80 Tarsi 38 Trachoma forceps 59 Tendinous ring of ciliary muscle 82 Tarsi 27 Third month, eye at 114 Test, catoptric 131 Tailpiece 136 Test, candle 131 Upper lid, saggital section of, 25 Upper lid, vertical section of 34 Venae vorticosae 104 Vitreous 109 Vertical section, upper lid .34 "Wharton-Jones operation .35 Zonule of Zinn 82, 97 INDEX PAGi:. Annulus albidus 96 Accommodation 7, 14, 97 Arteria centralis retinae 79, 110 ** hyaloid 112 Acari 124 Angle, iritic 121 Abrus precatorius 58 Abscess of cornea 72 Anteria synechia 73 " capsular cataract 73 Annular staphyloma of Sclera 83 Agnew 41 Abscess of lids 30 Anchyloblepharon 36 Axis, optic 16 Artery, Ophthalmic 21 Anf;;!e of reflection 8 '* " incidence 8 Axis, Chief 10 Aberration, spherical 11 Aqueduct of Sylvius 15 Amaurosis 117 Amblypia 117 Atrophy of optic nerve 119 Blindness, snow 117 Bibliography 137 145 146 INDEX. Body, ciliary o . .94 Blindness, moon 99 Euphthalmus 83 Blenorrhoea 54 Bean, Jequirity . .58 Bowman's membrane 65 Burns of cornea 68 Bleijhafitis, acute 30 " ciliaris 31 " marginalis 31 Blepharospasmus 33 Blejiharophimosis 33 Burns of lids 37 Bulbus 15, 16 Baptista Porta 6 Binocular vision 7 Color 17 Cavity, orbital 19 Chauveau 19, 96, 113 Capsule, Tenon's 21 Cellulitis, orbital 23 Canaliculi 24, 39 Ciliary muscle of Riolini 24 Conjunctiva 26, 50 Conjunctival fornix 27, 50 Cilia 27 Chalazion . . . , 36 Contusions 37 Canals, hygrophthalmic 38 Canal of Petit 96, 112, 113 Conjunctivitis catarrhalis 51 ' ' purulenta 54- INDEX. 147 PAGE. Contagious ophthalmia 54 Canal of Cloquet 113 Crede's method 56 Cloquet, canal of 113 Conjunctivitis diptheretica 56 " trachomatosa 57 Crystalline lens 113 Conjunctivitis phlyctenulosa 60 Cataract 115 Conjunctival tumors 63 Cancer 64 Cornea. J 65 Corneal injuries 67 Canal of Schleram 121 Corneal wounds G7 " bums 68 " abrasions 68 " epithelium 68 Conjunctivitis verminosa 125 Cornea, imflamation of 68 " staphyloma of 69 Cysticercus 125 Corneal abscess 72 " ulcer 72 Catoptric test 131 Cataract, anterior capsular 73 Conjugate foci I33 Cicatricial staphyloma 78 Corpora nigra 95 Ciliary nerves, short 85 Circulus iridis major 86 " *' minor Rft 148 INDEX. PAOK. Ciliary body 94 Canal of Fontana OS Ciliary canal 96 Corpus ciliare 96 Canaera obscura 5 <:hief Axis 10 Center, optical... 10 Colors, primary 12 Cyclitis 98- Choroid 105 Canthi 24 Distance focal 10 Dilator pupillae 14, 85 Duration of luminous impressions 16 Degree " " " 16" Duret— stricture of lachrymal 42, 43 Dacryocystitis catarrhalis 42 " phlegmonosa 44 Diffuse keratitis 71 Differential diagnosis between— Conjunctivitis ) Scleritis Y 81 Iritis ) Distichiasis 33r Diphtheritic conjunctivitis 56 Duct — nasal 39 Dacryoadenitis 39 De Wecker 58, 81 Dislocation lachrymal gland 40 Differential diagnosis between- Con junctivitis catarrhalis T Iritis „, ■ ^ , y 61, 2r Trachoma ' Conjunctivitis folliculosis j INDEX. 14^ PAGE. Dermoid tumor 64 Decemet's membrane 66 . Equator 16^ Ether waves Ig Eyelids 20, 24 Exophthalraus 22, 123 Enucleation 23, 99, 125- Eyelashes 2V Eetropium 31, 34 Epilation 31 Ectopia lentis 116 Entropium 33 Excretory apparatus 41 Epiphora 41, 42 Echinococcus 125 External rectus muscle 47 Exenteration 127 Episcleritis 81 Fontana's spaces 121 Fornix 50, 27 Filaria lachryraalia 125 " papillosa 125 Fistula lachrymaiia 45 Fontana, canal of 96 Focal distance 10 Field of projection 12 Fovea centralis 110 Fossa, temporal 20 •' patellaris 112 Foramen, optic 21 Glands of Moll... 27 Glands, meibomian 28 150 INDEX. PAGE. Gland of Harder 30 Gland, lachrymal 20, 38 Great oblique muscle 48 Gonorrhoeal conjunctivitis 55 " ophthalmia 55 Granular lids 57 " conjunctivitis 57 Glaucoma 121 Humor, vitreous 113 Hyaloid membrane 112 Haw 20,28 Hyaloid artery 112 Hiatus, orbital 20 Helmholtz 128 Harder's gland 30 Hordeolum ^ 32 Hygrophthalmic canals 38 Hypertrophy of lachrymal gland 40 Hypopyon 72 Hernia of cornea 73 Introduction 5 Image, inverted 5, 15, 17 Interstitial keratitis 71 Incidence, angle of 8 Iris 11, 84, 86 " sphincter muscle of 14 Impressions, luminous 16 Image, position of 17 Inverted image 5, 15, 17 Injuries of sclera 83 " " cornea 87 Inflammation of cornea. ... 68 INDEX. 151 PAGE. Inferior rectus muscle 46 Internal " " 47 Inferior oblique " 48 Iritic angle 12t Iridectomy 91, 124 Irido-cyclitis 99, 125 Iris, tumors of 90 Iridavulsion 91 Irido, choroiditis 99 Internal ophthalmia 110 Jequirity bean 58 ' ' infusion 77 Keratitis 68 " vasculosa 70 " phlyctenulosa 70 '• interstitialis 71 " diffusa 71 ' ' parenchymatosa 71 " suppurativa 71 Keratocele 73 Lamina cribrosa 79 Lids, Abscess of 30 Ligamentum pectinatum 84 Lachrymal gland 20, 38 " " dislocation of 40 " sac 39 " gland, hypertrophy of 40 " duct 42 43 '* fistula 45 Luminous impressions 16 Lids, granular 57 Levator palpebrae superioris muscle 24 2ft 152 INDEX. PAGE. Light. 8, 11, 18- Lens 113 Ligamentum pectinatum iridis 96, 121 Liebold 127 lienticula fossa 112 Leucoma 77 " adherans 77 Muscle — Oiliary, of Riolini 24 Posterior rectus 46 Retractor oculi 46 Superior rectus 46' Inferior " 46 Internal " 47 External " 47 Superior oblique 48 Inferior " .48 Temporal muscle 20 Obicularis 24 Levator palpebrae superioris 24, 26 Muscle of accommodation 97 Meibomian follicles 50 Moll, glands of. 27 Meibomian glands 28 Membrane nictatans 20, 28 Method, Crede's 56 Membrane, Bowman's 65 • ' Decemet's 66 " Hyaloid -. 112 " Ocular 20 Meridians 16 Mites 124 Motor-oculi nerves 14 INDEX. 153^ PAGE. Macula lutea 15, 73, 110 Membrana pupillaris persistans 90 Moon blindness 99^ Nubecula 73 Nebula 73, 77 Nictatans, Membrana 20 Nerve, optic 79, 117 " oculo-inotor 48 Nerves, short ciliary 85 " fifth pair 98 Nictitation 33 Nasal duct 39 Oblique illumination • 132 Optic nerve 21, 79, 117 " '* atrophy of 119 " axis 16, 17 ** foramen 21 Optical center IC Orbits 7 Orbital cavity. 19 Ocukr sheath 20 " membrane 20 Orbital hiatus 20 Ophthalmic artery 21 Orbital cellulitis 22 " periostitis 23 ' ' tumors 23 Ophthalmoscope 128 Orbicularis muscle 24 Ora serrata 94, 107 Ophthalmia, sympathetic 99, 103 " tarsi 81 154 INDEX. PAGE. Ophthalmia, periodic 99 Operation, Wharton Jones 35 Opthalmia, internal 110 Oeulo-motor nerve 48 Onyx 72 Operation, Saemisches 74 Ophthalmia contagiosa C4 " catarrhalis 51 * * gonorrhoeal 55 " neonatorum 55 Phlyctenular conjunctivitis 60 " keratitis 70 Punctum lachrymalia 24 Parenchymatous keratitis 71 Phtheriasis 31 Paracentesis 74, 75 Ptosis 33 Pannus 76 Puncta 39 Porous opticus 79 Phlegmonous dacryocystitis 44 Posterior retractor oculi muscle 46 Pink eye 51 Paralysis of muscles 48 Purulent conjunctivitis 54 Poles of the eye 16 Petit, Canal of 112, 113, 96 Panophthalmitis 22, 98 Position of image 17 Periorbita • 20 Pterygium 63 Pinguecula 63 INDEX. 155 PAGE. Periostitis— Orbital 23 Palpebrae 20, 24 Preface 4 Persistent hyaloid artery 113 Prism 12 Primary colors 12 Projection, field of 12 Purple, visual 13 Pentastoma Tsenoides 125 Periodic ophthalmia 99 Pectinate ligament 96 Reflection, angle of 8 Rods and cones 15 Riolini, ciliary muscle of 24 Recurrent opthalmia 99 Retina 106 Roemer 18 Sound waves 18 Squint 49 Staphyloma of cornea 69 Suppurative keratitis 71 Spherical aberration 11 Superior rectus muscle 46 Staphyloma, cicatricial 78 Sphincter muscle of the iris 14 Simpathetic cervical 14 Sylvius, aqueduct of 15 Sclera 79 Staphyloma of sclerotic 81 Sight 18 Steele 13 Sheath, ocular 156 INDEX. FAOK. ^lerotic, staphyloma of el Scleritis 18 Sclera, annular staphyloma of 83 Sebacious glands 27 Staphyloma, annular of sclera 83 Stye 32 "Symblepharon 35 Sac, lachrymal 39 Soot-balls 85 Sphincter pupillae 85 Short ciliary nerves 85 Stricture, lachrymal duct 42, 43 Synechia. , 87 Superior oblique muscle 48 Small " " 48 Strabismus 49 Sympathathic ophthalmia 103 Snow blindness 117 Spaces of Fontana 121 Synechia, anterior 73 Saemische's operatio^ 74 Schlemm, canal of 121 Tinia tarsi 31 Tarsi 26 Tumors of conjunctiva 63 Tract, uveal 84 Third pair of nerves 14 Tumors of iris 90 Tapetum 7 Test, catoptric 131 Trigeminus 14 Temporal fossa 20 INDEX. 157 PAOC. Tumors, dermoid 64 Tenon's capsule 21 Tumors of orbit 23 Trachoma 57 Trichiasis 33 Uveal tract 84 Uvea 85 Ulcus cornea 72 Visual purple 18 Vision 7 Visual axis 16 Vascular keratitis 70 Venae vorticosae 105 Vitreous humor 112 Von Graefe 124 Warts 64 Wounds of cornea 67 " lids 37 Xerophthalmia 63 Yellow spot... 15, 17, 110 Zinn, zonule of 14, 94, 112, 113 BIBLIOGRAPHY. Ophthalmic and Otic Memoranda Roosa. Encyclop. Brit. Article Optics. Physiology of Domestic Animals Smith. Ocular Therapeutics De.Wecker^ Diseases of the Eye Notes. Physics Steele. Ophthalmic Diseases and Therapeutics. ..Norton. Comparative Anatomy of the Domestic animals Chauveau. Popular Scientific Lectures IIelmholtz.. Six Lectures on Light Tyndall. Journal of Ophthalmology, Otology and Laryngology, N. Y. Yade mecum of Equine Anatomy Liautakd. Diseases of the horse, B. A. L, 1890 Law. Pathology and Treatment of Glaucoma . . .Smith. Lectures on the Human Eye Alt. Diseases of the Eye Berry. Diseases of the Eye Nettleship. American Journal of Ophthalmology St. Louis. JAN 1 .a 2000 .UN -2 im