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THE FORMAL FUNDUS OF THE EYE.
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A TEXT BOOK
OF
VETERINARY OPHTHALMOLO&Y
GEO. G. VAN MATER, M.D., D.V.S.
Professor of Ophthalmology in the American Veterinary College} Oculist and Aurist to Si. Martha'' s Sanitarium and Dispen- sary ; Consulting Eye and Ear Surgeon to the Tioenty- sixth Ward Dispensary ; Eye and Ear SurgeoUy Brooklyn Eastern District Dispensary, Etc.
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CoPTBiGHT, 1897, by William R. Jenkins
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IS AFFECTIONATELY DEDICATED
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PREFACE.
My excuse for perpetrating this work consists in shifting the blame on the students who so often have asked me to recommend something that could he studied without necessitating the perusal of many pages. And so this is the result. I lay claim to but little originality, although what I have told is the result of conscientious study, supplemented by practice, both private and clinical, and careful observation. Let me hope, therefore, that my motives will be taken into consideration by any critic who may deem this publication worthy of notice.
A TEXT BOOK
YETERINARY OPHTHALMOLOGY
INTRODUCTION.
The visual apparatus consists of the eyeballs and their accessory parts. The means of communication to the brain are the optic nerves. Each eyeball {Bidbus) forms a hollow spherical box, blackened in- teriorly, with a system of convex lenses, in front, for forming images of external objects, and the retina behind, which is the perceptive membrane. The whole
Fig. 1.— Formation of an image in the eye. (Landois.)
By following the rays from the object A B, it may be seen that they are brought to a focus on the retina, where a small inverted image is formed.
is likened to a camera obscura. A camera obscura is an optical apparatus, consisting of a darkened chamber, at
6
VETERINARY OPHTHALMOLOGY.
the top of which is placed a box or lantern containing a convex lens and sloping mirror, or a prism combining the lens and mirror. The rays of light from surrounding objects are received by the lens, and the mirror reflects images of the scenery downwards on a table placed underneath (invented by Batista Porta in the end of the 16th century). Now the light passes through the cornea, aqueous humor, lens and vitreous humor, and is focussed on the retina. The retina appreciates both intensity and color. Images which are formed on the
Fig. 2.— Scheme of accommodation. (Lnndois.)
The right side of the figure represents the condition of the lens during ac- commodation for a new object, and the left side when the eye is at rest. The letters indicate the same parts on both sides ; those on the right side are marked with a stroke. A, left, B, right half of the lens : C, cornea ; S, sclerotic ; OS, canal of Schlemm ; VK, anterior chamber ; J, iris ; P, margin of the pupil ; V, anterior surface ; H, posterior surface of the lens ; R, margin of the lens ; F, margin of the ciliary processes ; A B, space between the two former ; the line Z X indicates the thick- ness of the lens during accommodation for a near object ; Z Y tha thickness of the lens when the eye is passive.
retina are inverted. (Fig. 1.) These impressions are conveyed to the brain by the optic nerves, and thence
VETERINARY OPHTHALMOLOGY. 7
we have resulting — vision. Vision in all animals de- pends on the sensibility of the retina (optic nerve filaments) to the vibration of luminous rays. The amount of light admitted to the eye is regulated by a curtain, the iris, the movements of which are reflex. The eye adjusts itself (accommodation) for distances, so that the retina is properly focussed for distance and for objects near by. (Fig. 2.) At the base of the horse's eye is found a collection of pigment cells — bril- liant— called the tapetum, and in a darkened stall one may get the reflex from the eye, bluish in coloi-, more of a yellow in the ox and reddish-yellow in the cat.
In the horse the eyes are placed in their orbits in- clined toward the sides. Only a portion of a view is
Fig. 8.
perfectly appreciated at one time, the surrounding being less and less distinct, but from the perfect action
8 VETERINARY OPHTHALMOLOGY.
of the extrinsic muscles the bulbi are rotated so exten- sively and with such harmony that the field is quite extensive. Where rays of light proceed from a lumi- nous body, they always pass in straight lines, forming in their divergence a cone, the apex of which is the luminous body, and the base any plane which may in- tercept them. So long, then, as they travel in a medium of uniform density, so long will they travel in straight lines. Rays passing from a rarer to a denser medium are bent toward the perpendicular at the point of inci- dence. (Fig. .3.) Should they fall upon ?^polislied sur- face perpendicularly, they will be reflected in a straight
line. If obliquely, they will be reflected, and the angle of re- flection is equal to the angle of incidence. (Fig. 4.) If they pass ^'^■*' from a denser to a
rarer medium, they will be bent from the perpendi- cular (see Fig. 3).
If a luminous ray passes through a piece of glass, the ray striking obliquely, it will be bent toward the l^erpendicular, but, on its passing from the glass to the air (denser to rarer), it will be bent cmay from the per- pendicular. We have seen rays of light passing through plane surfaces. Let us see it through curved surfaces. It is supposed the circumference of a circle is made up of a number of small, straight lines. Take
VETERINARY OPHTHALMOLOGY. ^
a double convex lens. (Fig. 5.) Rays of light passing through this are bent toward the perpendicular, and
Fig. 5.
Diagram illustrating the composition of a convex lens of a numbex of plane surf acea.
therefore these rays come to a focus ; and where the focus is, we will find light and heat, because of the num-
Fig. 6.
ber of light and heat rays converged at one spot. Re- member that a ray strikmg a plane perpendicularly
10 VETERINARY OPHTHALMOLOGY.
will not be acted upon, but will pass through un- changed, and this is the chief axis.
The distance between the central point of the lens and the focus is the focal distance. If the diiection of the rays are reversed and tliey proceed from a luminous point at the focus, the rays will emerge from the lens, parallel.
When the distance of the light from the lens is equal to the focal distance, the focus will lie at the same distance on the opposite side of the lens, or ticice the focal distance.
If the luminous point approach the lens, the focal point is moved farther away. If the rays proceed from a chief point on the chief axis between the lens and principal focus, they will diverge on the opposite side of the lens, and not come to a focus. (Fig. 7.) In
I
Fig. 7.
ordinary lenses, the refraction is not equal in amount at the center and periphery.
Rays passing through the optical center are not re- fracted, while those which pass near the center are less
VETEEINAKY OPHTHALMOLOGY. 11
refracted than those which pass near the circumference ; so, you see, the nearer the circumference, the more the amount of refraction. This is called spherical ab- erration, which maybe corrected as follows : — Increase the density of the central part of the lens, which will cause it to act more strongly on the rays. Now see : this is just what the lens (crystalline) does in the eye, as it is more dense in its center than periphery. Or,
Fig. 8. Tlierays passing through the edges of the lens have a shorter focal dis- tance than those passing nearer to the center.
placing a diaphragm between the object of which the image is to be formed and, the lens, thus cutting oft' those rays which pass through the peripheral portion of the lens, the image therefore being formed by the rays passing through the center. This is also a con- dition existing in the eye, for have we not the iris, and what is the iris but a diaphragm, which is capable of modification? Xow, light, after all, is a composite
12 VETEKINAKY OPHTHALMOLOGY.
affair, being composed of seven colors, — violet, indigo, blue, green, yellow, orange and red. One may demon- strate this by using a triangular jiiece of glass — a prism — and intercepting a beam of light, which will be split up into its component parts, the red rays being
Fig. 9.
Diagram illustrating the decomposition, in passing through a prism, of white light into the seven colors of the spectrum (Biclard) : r, red » o, orange ; j, yellow ; v. green ; b, blue ; i, indigo ; vi, violet.
refracted the least and the violet the most. It is not the province of a small compilation, such as is repre- sented by this little work, to give full details in the physiology of sight. That must be culled from your various text-books on physiology. That point at which the image is focused on the retina is called the " field of projection." Here the visual purple becomes bleached
VETEEINARY OPHTHALMOLOGY.
13
rig. 10.
Anterior portion and ciliary region of the eye. C, cornea ; c S, Schlemmls canal ; O s, ora serrata ; 1 p, pectinated ligament : e F, Fontana's space ; T, tendinous ring ; m, meridional fibers ; c. circular fibers of the ciliary muscle ; Z, zone of Ziun. The full lines indicate the crystalline lens, iris, and ciliary body in a state of rest, the dotted lines show the same in a state of acci mmoJation.
14
VETERINARY OPHTHALMOLOGY.
- — undergoes change — and its action and function is now the subject of much question.
The question of inverted images, etc., will be more fully dealt with in the lecture-room. Accommodation is that faculty of the eye of adapting itself to distances of varying degree, and is accomplished by the action of the ciliary muscle upon the capsule of the lens, through the zonule of Zinn. When accommo- dated for near objects, the pupil contracts; when 'for more distant objects, the obverse is the case. These changes (contraction and dilation) are reflex, and are brought about by the action of two sets of fibers (muscular) — the sphincter, which are circular, sup- plied by the .3d pair (motor-oculi) ; and the dilator pupillce, which are the radiating fibers, supplied almost entirely by the trigeminus and the ■"'"^ cervical sympathetic, Now, sup- p, pigment Uii Of, the re- po^© wc divide the 3d, what results ? tina connected \vith a DHates of coursc ; and why ? The
rod. n, Cone seated on ■
the membrana liniitans Sympathetic gcts in its work and is
externa. .„,,
in lull possession of the field ; the dilator fibers contract, and a wide open pupil is the result. On the other hand, cause a solution of con- tinuity in the sympathetic, and contraction is the re-
VETERINARY OPHTHALMOLOGY. 15
suit. The sphincter fibers contract and narrow down the pupil. If both nerves be stimulated simultane- ously, we will observe that the sphincter set are the more powerful, for contraction will ensue. In the pre- sence of bright light we have contraction. Stimulation in the floor of Aqueduct of Sylvius causes contrac- tion. Pupillary caliber is modified by action of certain drugs, of which more hereafter. The retinal action and its results are far from being satisfactorily explained to the ophthalmic student, as yet. We know that it is the rod and cone layer only, which is con- cerned in the formation of the image. The most acute vision is at the macula lutea, or yellow spot. We will speak of only the rod and cone layer in this part of our little brochure, and under the retina will delve deeper into its layers.
The external layer, consisting of rods and cones closely packed together, *'. e., small transparent rods, end on, close together, and scattered among them with- out regularity, a cone here and there. At the macula we find numerous cones and an absence of rods. Also at this place, find ganglionic and yellow pigment cells. Now, remember, light is a sensation only.
Remember, also, we spoke of the visual purple. As yet we know not of its i^recise function, but that it is concerned in the perception and recognition of light, there is no reasonable doubt.
The movements of the bulbus in its socket are of
16 VETERINARY OPHTHALMOLOGY.
the universal order known as ball-and-socket joint. Luminous impressions upon the retina continue for a short time after cessation of light. If a bright point, like a smouldering or glowing match end, be waved around in a circle, the eye follows it throughout, but if tlie rapidity of its motion be increased it appears drawn out into a curved line, and with higher motion, veiy fast, it becomes a complete ring of light. Sparks from a knife-grinder's wheel become a stream of light. A circular saw with large teeth presents a smooth edge when revolving rapidly, and the spokes of a rapidly- turning wheel assume the appearance of a glimmer- ing disc.
A brilliant light leaves a longer impression than a dim one. When an electric spark is seen, it has already come to an end, the interval elapsing before its perception by the observer being greater than its actual duration. The momentary closing of the eye- lids in winking is unnoticed, and why ? Because the visual impression of external objects continues unim- paired during the interval occupied by the movements of the lids. The eyes of the horse, remember, are set obliquely. Only in man, apes and some night-birds are the eyes so set as to permit visual lines directly ahead in parallels.
The bulbus has its poles. An imaginary line from pole to pole is its axis. The equator is at right angles to the axis, so we may have meridians. The visual
VETERINARY OPHTHALMOLOGY. 17
axis corresponds to the macula lutea, while the optic axis extends from pole to pole.
"We are not aware of an image being on the retina, nor of its position there, but only of the stimulus pro- duced, on the perceptive nerve elements of the retina. So, understand, we do not see the image, but the object from which the rays emanate, and we refer the sensa- tions in their direction. For instance, if an image is formed on the upper and outer quadrant of the retina, we refer it doxcmrard and imcard., from which direction the rays must have come. At this point a word on inverted images: — The great advantage of inverted images is, that for a given-size pupil a much larger picture can be formed on the retina than would be the case if no inversion took place, for in the latter case all images must necessarily OQCWYty 2i much smaller place upon the retina than the size of the jyujnl.
Color is analagous to pitch, violet corre- sponding to the high, and red to the low tones. Intensity of color, as of sound, depends upon the amplitude of the vibrations. "When a body absorbs all the colors of the spectrum except blue, we call it a blue body. lied glass has the power of absorbing all the colors except
18 VETERINARY OPHTHALMOLOGY.
the red, which it transmits. If any body or thing- reflects all colors, we have white. Should all the colors^ be absorbed, we have black. Light travels 186,000 miles per second (discovered by Roemer in 1676). Scientific- ally this is of great moment, but to us the rate is so great that, for all distances on earth, it is instantaneous. The globe would be girt by a sunbeam quicker than we could wink. The theory of to-day as regards light is the undulatory theory. The earth is supposed to be bathed, embalmed, enveloped by a fluid termed Ether, which is very subtle. Suppose a luminous body sets in motion waves of this Ether which go in every direc- tion, moving, remember, at the rate of 186,000 miles per second. Well, these waves breaking upon the retina cause the molecular disturbance termed " sight." This wave motion is like that of sound, except that the vibrations are transverse — cross-wise. " The sunbeam comes to the earth as simply motions of Ether-waves, yet it is the grand source of beauty and power. Its heat, light and chemical force work everywhere the miracle of life and motion. In the growing plant, the burning coal, the flying bird, the glaring lightning, the blooming flower, the rushing engine, the roaring^ cataract, the pattering rain, we see only varied mani- festations of this one all-energizing force." * * Steele.
CHAPTER I. ORBITAL CAVITY.
Orbital cavity. — According to Chauveau, this cavity is irregularly circular in outline and circumscribed by the orbital process of the frontal bone, the lachrymal
Fig. 13.
and malar bones, and the summit of the zygomatic process. At the bottom, which shows the maxillary and orbital hiatus, it is confounded in the skeleton with the temporal fossa.* It lodges the globe of the
* A fibrous membrane, the ocular sheath, isolates it from the temporal fossa in the majority of mammiferous animals. Only in 19 .
20 VETEEINARY OPHTHALMOLOGY.
eye and the muscles which move it. Some organs accessory to the visual apparatus, such as the lachrymal gland and the membrana nictatans, are also contained in this cavity. The temporal fossa sur- mounts the orbit and is incompletely separated from it by the orbital arch (or process). Oval in shape, lying obliquely from above to below, and from within out- wards, on the sides of the cranium, the temporal fossa is limited, within by the parietal ridge, and outwardly by the anterior border of the longitudinal root of the zygomatic process. It lodges the temporal muscle.
The orbital cavity is situated at the side of the head at the point corresponding to the union of the cranium and the face. It is lined by a fibrous mem- brane, designated the ocular sheath (ocular membrane or periorbita), which is attached posteriorly to the bor- der of the orbital hiatus and anteriorly to the upper lip of the orbit, being prolonged beyond the exteinal lip of this osseous rim to form the fibrous mem- brane of the eyelids. Strong externally, the ocular sheath is thin within the cavity, composed of elastic and inelastic fibers (unstriped muscular fibers have also been included in its composition), traversed by vessels and nerves. Thus completed, the orbital cavity lias the form of a regular hollow cone, open at its base,
man and the quadrumana has the orbital cavity complete bony walls.
VETERINAEY OPHTHALMOLOGY. 21
closed at the apex, which corresponds to the orbital hiatus. In the ordinary position of the head the open- ing of this cone is directed forward, downward and outward. The bones which go to make the orbital cavity are the frontal, sphenoid, superior maxillary, malar, palate, ethmoid and lachrymal. The optic for- amen, situated at the apex of the cone, transmits the optic nerve and ophthalmic artery. The superior orbi- tal fissure transmits the third, fourth and sixth nerves, ophthalmic branch of the trigeminus and the superior and interior ophthalmic veins. The inferior orbital fissure gives passage to the malar and infra-orbital nerves, and a facial branch of the ophthalmic vein. (See Fig 41.) The supra-orbital notch, at the upper and inner margin of the orbit, contains the supra- orbital nerves and artery as they pass to the forehead. In addition to the bulbus, muscles, vessels, etc., the orbit contains much adipose tissue.
There is a limiting membrane between the globe and conjunctiva and the cellulo-fatty tissue, called Tenon's capsule. To some extent it ensheaths the muscles, nerves and vessels that pass through it, and is con- tinuous with the periosteum of the orbit, as Avell as with the conjunctiva. It is somewhat analogous to the pleura, and serves as a cup in which the globe revolves. It constitutes a secondary attachment for the ocular muscles. The dura mater is firmly attached at the sphenoidal fissure and optic foramen, and is continuous
22 VETERINARY OPHTHALMOLOGY.
with the outer sheath of the optic nerve and with the periosteum of the orbit.
OrMtal cellulitis. — Diseases of the orbit may be either simple oedematous cellulitis or phlegmonous cellulitis. In the oedematous form there will be bulging forward of the bulbus. Little pain on pressure occurs in the young and subsides in a few days. The phlegmonous form is much more severe ; swelling of the lids, especially the upper ; pain, which may be intense and will tolerate no pressure on the globe ; eye is pro- truded directly forward.
Exophthalmus. — In some severe cases have abso- lutely no motion; * will have cheraosis of conjunctiva; symstoms almost always acute, and the crisis is reached in 8 to 14 days. Tissues on palpation will be found firm, tense and hard. All this may go on, the bulbus become involved and have inflammation of all parts of the eye—jxoiojyhthalmitis. When pus forms, as it may, fluctuation may be found behind the lids. Abscess may burst through conjunctiva or lids. May result from injuries, periostitis and inflammation, of lachrymal gland.
Treatment. — Antiphlogistics early. Should sup- puration occur, poultices and incision through conjunc- tiva between the lids. Exploration is good when in doubt, and better to use knife too early than too late. A large majority of these cases recover, and about the
* Compare periostitis.
VETERINARY OPHTHALMOLOGY. 23
only untoward results are abscess of brain and menin- gitis. Don't be fooled, when the whole thing may be a simple foreign body, the removal of which will dis- sipate the alarming symptoms.
Periostitis of the Orbit is generally limited to the margin of the orbit. It may arise idiopathically in the rheumatic. Some swelling and redness of the lids and a slight exophthalmus, generally to one side. Some- times slight elevation of temperature. Pus may form beneath the periosteum. In the chronic form there is simply slight swelling of the upper lid and supra-orbi- tal pain, and a little local swelling. This form is very tedious, running months, and ending in caries, deformi- ties, etc.
Treatmext. — As in cellulitis. If, however, it has gone on to necrosis, etc., the chisel and gouge come into play, and a thorough removal of and curetting is applied to the carious parts.
Tumors of the Orbit. — Both benign and malignant. May develop primarily in the orbit or spread from the face. Cause more or less exophthalmus and its conse- quences.
Treatmext is excision. Sometimes it is necesary to remove bulbus also : {Eneucleation.)
CHAPTER II.
EYELIDS.
The eye is protected and covered by two mem- branous, movable curtains — tlie palpebrse — superior and inferior. Tliey serve to protect the eye and to exclude excessive light. Another function is to secrete and distribute a moisture to the eye. Their movements are both voluntary and involuntary, the involuntary due to the orbicularis muscle. The levator palpebrse superioris opens the eyes by lifting the upper lid. The space between the free margins of the lids is the pal- pebral fissure. The angles of junction between the lids are the canthi, the external being the most acute. At the inner canthi are found two small elevations, one on each lid — the lyunctum lachrymale — which are the be- ginnings of the canals, or canaliculi., letiding to the tear sac. The eyelids are composed of four layers : (1) the in- tegument, (2) layer of muscular fibers, (3) the tarsus, and (4) the conjunctiva. The muscular fibers consist of the orbicularis palpebrarum, a wide, thin sphincter common to both lids, having tendinous attachments at the angles
of the lids, the tendons together with some muscle- 24
VETERINARY OPHTHALMOLOGY.
25
Fig. 14. Saggital Section through the upper eyeUd. 1, skin ; 2, palpebral portion of the musculus orbicularis oculi ; 2a, its inner portion, designated a8 the musculus ciliaris Riolini ; 3, cilia; 4, gland of Moll, opening into a hair follicle ; 5, Meibomian gland ; 5 a, its orifice ; 6, indication of the ill-defined limit of the tarsus ; 7, loose connective tissue between tarsus and anterior insertion of the tendon of the musculus levator palpebrae superioris ; 8, anterior eonnective-tissue-like insertion of the tendon of the musculus levator palpebrae superioris : 9. its middle layer, non- muscular, called the musculus palpebralis superior.— JS^. Muller.
26 VETERINARY OPHTHALMOLOGY.
fibers being attached to the bony wall. There are certain bundles of the orbicularis fibers— involuntary — known as the ciliary muscle of Hiolini. The orbicu- laris is adherent to the skin, but glides smoothly and loosely over the tarsus. The contraction of this muscle closes the palpebrse.
The Levator PaJpehrm Sux>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?<s/i and sup. port the eyelid in its pro- per position, causing the sutures to assume a Y- like appearance. This is the Wharton Jones operation. (See Figs. 19 and 20.) When we find an eyelid fast to the eye-ball the condition is known as Sij7nhle2)/iaron. Is the re- sult of burns, severe in- flammations, such as con- junctivitis, or anything Avhicli will cause the de- struction of the mucous membrane. This grow- ing together may be partial, or, we should say, of more or less extent. For instance, the entire lid may be adhered to the
Fig. J
S6
VETERINARY OPHTHALMOLOGY.
globe, and again it may be only a thread-like attach- ment. The treatment is to separate and keep apart un- til the parts are healed over. This may necessitate transplantation from other portions of the globe, or borrow from a rabbit's eye. An adhesion, growing together, of the lid margins, is Anchylohlepharon, com- plete or partial.
Treatment is division. (See. Fig. 21.) Chalazion is obstruction of some of the follicles of the tarsus with re- tention of its secretion. The diagnostic point is that the skin is freehj movable over it. Vary in size, and are apt ta come in crops. Fluctua- tion is never felt. Ex- cision is the treatment. Make the primary incision on the skin ^wxh^Q^— parallel to the lid border. May open on the inside if it points that way. This has a sac wall, remember, which must be either removed or tlioroughhj scraped, curetted, spooned out. Cocaine will be the only anaesthetic needed, dropping some of a 4 per cent, solution into the conjunctival sac and hypodermically injecting some alongside the tumor, which will render the operation nlmost painless. May lightly touch with lunar caustic to insure healing. All operations upon the lids are
Fig 21
VETERINARY OPHTHALMOLOGY. 37
productive of free hemorrhages, which may be very
successfully controlled by using a clamp such as this.
Contusions should be treated as contusions elsewhere.
Fig. 22.
Immediately after a contusion, cold compresses, firm bandaging, cooling and soothing lotions, etc.
Burns and Scalds.— The great care is prevention of adhesions. If lime is the burning cause, antidote it immediately with acids, vinegar, etc., or protect with oil, freely used. Do not wash out the conjunctival sac unless you hviVQ plenty of water. A small amount would but aggravate the condition by slaking the lime.
Wounds. —Treat as elsewhere; cleanliness, antisepsis. Carefully inquire into the condition of the parts sever- ally and as a whole. Careful coaptation of the wound's lips, intelligent suturing, and watch out for adhesions always.
CHAPTER III.
THE LACHRYMAL GLAND.
Laciirymal Gland. — Situated between the orbital process and upper part of the eyeball and close to its interior margin, convex superiorly, concave inferiorly. Is an acinous gland, formed of small granulations,
Fig. 23.
whose junction forms ducts called hygrophthalmic canals. These run to the upper and outer portion of
38
VETEEINAEY OPHTHALMOLOGY. 39
the superior fornix of the conjunctiva. Secretion is alkaline, moistens anterior surface of the eye, passing off by means of the puncta, canaliculi, lachrymal sac and nasal duct to the nose. The puncta are two openings of the canaliculi, at the inner canuhus, a short distance from the commissure. Function, to collect the tears. The canaliculi extend from the puncta to the lachrymal sac, and these canaliculi join before reach- ing the lachrymal sac. The lachrymal sac is the upper dilated portion of the nasal duct, which is situ- ated in a groove or osseous canal in the lachrymal bone. Terminates between the two turbinated bones. The balance of the canal is under the nasal mucous mem- brane, passes to inner surface of outer wing of the nostril, terminating by an orifice (sometimes two) toward the lower commissure, where the line of de- marcation between the skin and rosy mucous mem- brane presents.
The tears are forced into the excretory passage by muscular action and some kind of suction caused by the muscular fibers of the puncta and canali- culi.
Dacryoadenitis. — Very rare indeed. Symptoms of the acute form are great swelling and redness of the upper lid at its outer angle. The gland will be pushed out of its fossa downwards, by the inflammation and swelling, and may be recognized on everting the lid. The swelling may be so great as to displace the globe
40 VETERINARY OPHTHALMOLOGY.
down and inward. Suffering is pronounced. May- have an accompanying conjunctivitis, chemosis, etc. Sometimes confounded with periostitis. May have suppuration. Generally of traumatic origin.
Treatment — If early, ice may abort. So soon, how- ever, as there is suppuration, aid the formation with heat. Free incisions through the conjunctiva.
Dislocation of the gland has been seen and hyper- tropliij of the gland is exceedingly rare. This struc- ture may be the seat of new growths, as glandular structures, in other parts of the bodj'^, and should be treated as elsewhere, i. e., extirpation of entire gland.
CHAPTER IV.
EXCRETORY APPARATUS.
Excretory Apparatus (Diseases of). — As a result of in- flammations ; of the conjunctiva and lids ; wounds of the lid; narrowing and stoppage of the canaliculus; may have watering of the eye (Fpiphora). If ob- struction of the canaliculus, slittiiig the canal with a knife modeled by and bearing the name of Agnew is the treatment. This is a narrow-bladed, probe-pointed
A;::C-.v's Canaliculus Knife Fig. 24.
knife. Enter the puncta with its probe point, verti- calhj. Remember the anatomical disposition of the canaliculus in the angle of the lid M\i\.foUoio it. The idea is to open the already existing, but obstructed passage, and not to establish a new one. "When entered vertically,— and that takes patience, but the sphincter will yield to persevering pressure — depress the handle of the knife until it is horizontal. Push immrd until you reach the inner wall, keeping the lid on the 41
42 VETEEINAEY OPHTHALMOLOGY.
stretch. Bring the knife straight up and down and cut the whole length of the canaliculus. This is diia- cultof accomplishment in the horse, owing to the length of the canal ; but a knife with a malleable shank will facilitate matters much. Remember and divide the canaliculus close to the juncture of skin and mucous membrane, so that its function of collecthig the tears may be as little interfered with as possible, close coaptation to the conjunctiva being one of the factors of that important function.
Strictura of the Lachrymal Duct.— Most common of all the lachrymal affections. Its one symptom is a flowing of tears— Epiphora. May be result of catarrh, trauma, carious teeth, pressure from tumors, and peri- ostitis.
Dacryocystitis Catarrhalis. — Seldom recognized be- fore the chronic stage. Practically no difference be- tween this and catarrh. Will find a swelling at the in- ner angle of the eye, caused by a retention of secretion from the catarrhal inflammation, and swelling, lessening the caliber of the excretory ducts. Firm pressure on this swelling will cause mucous to flow from either the canaliculus or down the duct, into the nasal cavity. The swelling is generally painless. Keeping the sac empty affords some relief. Have generally a coexist- ing blepharitis marginalis. The secretion after a time becomes irritating, and this is especially the case when it is permitted to remain quiet some time in the sac.
VETERINARY OPHTHALMOLOGY.
43
Then it sets up conjunctivitis. It becomes infectious, and if it gain entrance to a wound of tlie cornea is apt to cause suppuration. In diagnosing, the question of tears decides. For instance, the tumor will be lessened by pressure and the contents come upwards through the puncta or descend to the nose. This might be the result with a very tight stricture, but of less degree, or the sac- walls may be very thick, but remem- ber the tears — Epiphora — and that is decisive. These conditions are rebellious — may continue for months. The cure of the underlying catarrh is imjierative. Any cause must be removed. Strictures must be dilated. May have to precede dilation by slitting the canalic- ulus, but dont slit the puncta if can avoid. Take, by preference, a pair of fine iridectomy forceps, and, gently insinuating the closed points into the puncta, dilate the s[)hincter until it i-elaxes, and will then be able to introduce a small probe (Bowman's). Then
Bowman's Set of Probes, Kos. 1. 2. 3. 4, 5, 6. 7. 8.
Fig. 25.
introduce a Stilling's knife and slit the stricture, using
JICMANNzr.O
Fig. 36.
44 VETERINARY OPHTHALMOLOGY.
same method as in probing. This knife being tri- angular, after introduction it is simply necessary to turn it in different directions and force it down two or three times. Blood issuing from the nose is proof of an open passage. In some instances it is impossible to gain entrance into the canaliculi without nicking the puncta, but remember that you are apt to destroy the normal function of the parts, impairing its suction powers. Electrolysis has produced good results — in- troducing a probe until reaching the stricture and at- taching the negative pole ; apply the positive to the tem- ple and make gentle pressure as the stricture yields. Repeat this until permanent results are achieved.
Lotions on the lids, astringents to the conjunctiva, are good. Arg. nit. gr. v to 31. Watch and treat the nasal catarrh. Dobell's sol. is nice and successful.
]J . Sod. bibor., 3 iv.
Glyc, 3i.
Sod. bicarb.,
Ac. carb., aa § ss.
Aq., 3vi.
If this condition continues, becomes phlegmonous, it is called Dacryocystitis Phlegmonosa., and is a higher stage of the preceding. Have much swelling and ex- treme sensibility. Usually much infiltration of the sur- rounding parts. Constitutional symptoms very often. Conjunctiva may be inflamed and even chemosed.
VETERINARY OPHTHALMOLOGY. 45
Must differentiate between this and abscess of the cellular tissue. In abscess, pressure will not reduce it, while in dacnjocystitls iMegmonosa the contents will be forced througli the puncta or down into the nose. And remember the previous history of long lachryma- tion.
Treatment is incision into the sac, and in ad- vanced cases (which are the only ones you will meet) this is the only treatment. Thrust the knife per- pendicularly down to the bone and carry the incision down as far as necessary. Keep the incision open with lint. If it has opened spontaneously, poultice for twenty-four hours, but not too long; maybe forty- eight hours of hot poulticing, but no longer. After this opening has closed it will be necessary to open the nasal duct and establish a passage for tears. Don't probe until subsidence of inflammation.
Lachryinal Fistula. — Result of an illy-healed abscess, and indicates the existence of a permanent stricture. Rarely seen. If possible, the re-establishment of the proper channel for the passage of tears should be the primary care. Then the fistula can be easily healed, treating as you would a sluggish fistula anywhere, stimulating its edges with lunar caustic, etc.
CHAPTER V.
MUSCLES OF THE EYE.
Muscles of the Eye. — Seven — loosterior, superior, in- ferior, external and internal recti, and superior and in- ferior oblique.
Posterior Rectus Rectractor Oculi, as its name implies, pulls the bulbus backward. Is a muscular sheath,.
Fig.
with fibers disposed longitudinally ; arises from around the optic foramen and inserted into the posterior part of the external face of the sclerotic. May be dissected into four bundles. Superior^ Inferior^ External^ andln-
46
VETERINARY OPHTHALMOLOGY.
47
temal recti. These are placed upon the posterior rectL Each is a flat band with parallel fibers. Origin at the
S.lni
Fig. aa
Scheme of the action of the ocular muscles.— Landow.
back of the ocular sheath aud inserted into the sclero- tic, by an aponeurosis. These muscles are separated
48 VETERIKARY OPHTHALMOLOGY.
from one another and the posterior by the fat belong- ing to the membrana nictatans. They act according to position, and, as I have demonstrated upon the board, according to concerted action.
Superior Oblique, or Great Oblique. — This arises from the back of the orbit and passes forward against the inner wall to pass through a strong flbro-cartilag- inous pulley, which is attached to the frontal bone at the base of the orbital process ; then, bending out- ward, passes beneath the superior rectus neaiiits at- tachment and inserts itself into the sclerotic between the superior and external rectus. Consequently this muscle pivots the eye inward and upward, carrying the outer aspect of the globe upwards and its lower part outwards.
Inferior or Small Oblique Muscle. — Thicker and shorter than the superior; is nearly parallel to the reflected portion of the superior. Arises in the lachry- mal fossa, passes outward and is inserted in the sclerotic between the external and inferior recti. In action it antagonizes the great oblique. The move- ments of the bulbus correspond to a ball and socket joint. The center of rotation is a short distance be- hind the center of the eye.
The oculo-motor nerve, or third pair, supplies all the muscles of the eye except the external rectus and supe- rior oblique, which are supplied by the sixth and fourth pair respectively. These muscles are susceptible to
VETERINARY OPHTHALMOLOGY. 49
paralysis, individually and collectively. When indivi- dual muscles are affected we find restricted motion^ converse to the action of the muscle when physiolo- gically exerted. If complete paralysis of the third pair occurs, then have ptosis, some exophthalmus, ditto dilatation of the pupil and accommodation paralyzed. Movements restricted in all directions, except directly outward.
Strabisimus or Squint-Many varieties. Usually mono-lateral, which is a faulty position of one eye. May be alternating-the ability to fix with either eye. Also have intermittent or constant.
Treatment is operative; divide the tendon of the contracting muscle.
4
CHAPTER VI.
THE CONJUNCTIVA.
Conjunctiva. — A delicate, fine mucous membrane ; lines the inner surface of the lids. From the lids it is reflected upon the bulbus and extends to the cornea, covering the sclerotic. It is continuous with the cornea. Consists of three layers — external being- epithelial, the intermediate being the proper tissue and tbe subconjunctival tissue. The palpebral conjunc- tiva especially contains numerous lymphatics and glandular structures. The conjunctiva in its reflec- tion from lid to bulbus forms the cul-de-sac or fornix. Highly supplied with nerves from the fifth pair (tri- geminus). Also well furnished with blood, and especi- ally so around the limbus. The conjunctiva has the important function of luhrication. The membrane is divided into three distinct portions : Tarsal, which is smooth, and fits the tarsi (the Meibomian follicles may be seen through it) the fornix, sinus and cul-de-sac being the reverse, loosely attached and easily mov- able, and is dark in color, while the tarsal is of a light yellow; and third, the ocular portion which lies loosely,
but smoothly, upon the globe, and this fact aids in 50
Veterinary oPHTHAXMOL-aGY. 51
diagnosing between conjunctivitis and inflammations •of a deeper nature.
Conjunctivitis Catarrhalis. — Pxirxdent (which may be idiopathic or gonorrheal, JDiphtheretic^ Granular^ Phlyctenular^ these are some of the forms of inflam- mation of the conjunctiva, one of which may run into another. The discharge from one kind may reproduce itselt or one of another form. They are contagious and infectious. May occur epidemically. Pink-eye is but an epidemic catarrhal conjunctivitis. A differentia/ diagnosis is often impossible early.
Catarrhal Conjunctivitis. — Catarrhal ophthalmia is the mildest form. Caused by injuries, exposure, bad hygiene, exanthematous diseases, etc. Again, it may be secondary to other inflammations. Among the symp- toms we find smarting preceded by itching, lachryma- tion, sensation of sand or of some other foreign body in the eye. Have increased vascularity, causing partial or uniform redness of the ocular conjunctiva and impart- ing to the palpebral conjunctiva a velvety, roughened ap- pearance. CEdematous swelling of the conjunctiva and subjacent tissue, which may go on to chemosis, causing- the cornea to look sunken. Redness, swelling and stiff- ness of the lids. Mucus or muco-purulent discharge, with tendency toward agglutination of the lids, espe- cially succeeding sleep. Both eyes usually participate, although one eye may go free. This form is amenable to treatment and not very apt to invade the cornea.
62 VETERINARY OPHTHALMOLOGY,
Now, when the front of the eyeball is red, it is impor- tant to know whether the congestion is superficial or deep. If superficial, the redness will he conjunctival and will appear as a coarse network of blood vessels, running over the sclerotic very irregularly and in no order at all, or by a more uniform redness which, nearly conceals all the white of the globe. If the con- gestion and swelling are not very great, the edge of the lower lid rubbed against the globe by the finger may be seen to move the vessels over the sclerotic and to press the blood out of them. The inner surface of the lids will be congested also, and there will be a mucous or muco-purulent discharge, with probably not very much photophobia. In deep, or ciliary conges- tion, there is a rosy zone of straight, fine vessels, as I here draw upon the blackboard, and, as you see, resem- bling the rays of a brilliant sun. Very regular, straight as an engraver's lines, totally different from conjuncti- val injection, which is highly irregular and of a grape- vine order. These straight fine lines nxdinte from the corneal margin. They are immovable under press- ure through the lower lid, while the conjunctival, re- member, are movable, and the blood may be pressed out of them. On close inspection the rosy zone is seen to lie beneath the conjunctiva, in the sclerotic. When we find this form of congestion, although it may be very slight, there will be, usually, pain, photophobia and profuse lachrymation, and the tears will be hoU
VETERINARY OPHTHALMOLOGY. 53
This picture indicates ciliary irritation and an affection of the cornea or of some of the deeper structures. Of course the two kinds of congestion are often found com- bined. When the exit of venous blood from the interior of the eye is impeded, large dark, tortuous veins will appear running over the sclerotic, which they penetrate near the edge of the cornea. It is important to learn, in the presence of inflammation, as to the existence of pain, tenderness in the ciliary region, which is the name given that region immediately surrounding the cornea. To this end, make gentle pressure over the closed lids' about this region using the index finger of each hand and palpating, as if for suspected abscess, for instance." Examinations are somewhat difficult owing to the photophobia. Will be facilitated by a drop or so of cocaine 4%. Use oblique illumination, as I have de-' monstrated in the clinic. Notice the mobility of the pupil and intra-ocular tension. '
Tkeatmext: extreme cleanliness, hygienic precau- tions, attention to general health. Topically, some mild astringent lotion every few hours. A caustic ap- plied at the outset may abort. Cold applications in the early stages are very good ; catarrhal conjunctivitis is," however, a self-limited affair, which often requires very little local treatment, and which, with good hygiene, ter-' minates in complete recovery. However, do not be too sanguine, but temporize, as it may extend a week or so longer than you expect, and so, give no definite progno- bIs as to time. ' -...;;
64 VETERINARY OPHTHALMOLOGY.
^ Sulph. Ziiic. grs. ij to the oz. of distilled water;
IJ Boric, ac, 4 % Sig. Gtt. j t. i. d., or oftener;or,
^ Ac. Boric, gr. xi].
Aq. Camph.
Ag. destill. aa 3 ij. M. Sig. Gtt. i. t. i. d. or oftener.
Purulent Conjunctivitis, Blennorrhoea, Contagious Ophthalmia. — This is like the catarrhal, but with in- tensification of all the symptoms. Due to the same causes. It often appears as an epidemic, where num- bers are crowded together with poor hygiene. Is met with in the Asiatic countries especially. The dis- charges are thick, purulent and very contagious. Very great danger of invasion of the cornea, which results in ulceration, sloughing and probable loss of the eye, within a short time.
Treatment. — Mild cases should receive same treatment as the catarrhal form. Severe cases re- quire isolation, darkness and quiet ; and, first, last and all the time, watch the pus, which 77iust 7iot be allowed to accumulate. Sometimes cleansing is needed every few minutes. Application of cold, l)leeding, scarification of the conjunctiva, if the swell- ing be pronounced and chemosis be present, and, if the lids press greatly upon the globe, canthotomy. When the discharga appears, astringent- lotions every few
VETERINARY OPHTHALMOI.6GY. 5i
hours and some caustic application, such as lunar caustic, to inner surface of lids, twice daily, or possi- bly once will sufiBce ; cold compresses, continuous or changed for warm ones if you like. Atropine if the cornea becomes involved. If one eye only be affected, the other must be guarded. May be sealed hermetically. When a case is seen at the very outset, thorough cleansing and a caustic application to the lids (pal- pebral conjunctiva) seems to abort.
Goncrrhoeal Conjunctivitis. — Gonorrhoeal ophthalmia. This does not differ, except in manner of origin, from any other purulent conjunctivitis, and of course in the equine race the groom must be looked to for an ex- planation. It is an extremehj violent purulent inflam- mation, caused by inoculation from the urethral dis- charge. It may destroy the eye in a few hours. Still another form of inflammation, in the newly-born, called
Ophthalmia Neonatorum. — This form is a catar- rhal or purulent conjunctivitis, usually appearing shortly after birth and caused by contact Avith the vaghial discharges of the mother. May also occur from other causes, such as exposure and filth, and not appear until several weeks after birth. Assumes all grades of severity.
Tkeatmext.— Same as in similar conditions in the adult, and should l)e reguhrted by the severity of the attack. It is believed by many that caustics are
66 VETERINARY OPHTHALMOLOGY.
needless in the very young. Even claim they ara injurious, and that a mild astringent application is all that is necessary. In practice among physicians the method of Crede is largely employed, which con- sists in dropping into the eye of a newly-born one drop of a 2/0 solution of Arg. nit. ; and it seems to me if there is any apprehension the same could be done by the veterinarian.
Diphtheretis Conjunctivitis is peculiar in that it may result from the same cause as the other forms. This begins with great heat, -redness, swelling and tenderness of the lids, with rigidity from fibiinous hifiltration.. Have firm swelling of conjunctiva from the same cause, and a pale, smooth, glistening appearance of its surface. Sometimes have a grayish exudation mem- brane on the conjunctiva, wliich may he stripped off. Discharge of flakes of lymph. Advanced stage is marked by softening of the parts and from the disap-, pearance of fibrinous matter and by discharge of pus. Great tendency to shrinking and formation of cica- trices of conjunctiva in healing. The cornea is apt to suffer, and constitutional disturbance is often marked.. This form is very destructive, and, fortunately, is rare in this country and England.
Treatment not very effectual. In the first stage ice compresses, local bleeding, etc.; astringents and caustics in the purulent stage. Atropine should be used, throughout.
VETERINARY OPHTHALMOLOGY. 57
Take a, case, for example : Diagnosis has been satis- factorily made. The eye is cleansed thoroufjhly. If much pain and restlessness present, instill a drop of cocaine 4% three times, at five-minute intervals. If the case has been brought you while young {%. e,, the case, not the patient), evert the lid and paint the palpebral conjunctiva with a strength suitable to the severity of the presenting symptoms, of nitrate of silver solution, even using the stick form in aggravated cases, neutralizing it vntli a saturated solu- tion of Sod. CIdoride, before the lid returns to its normal position. Then commence cold applications, which may be in the form of cracked ice, or pieces of clean cloth which have been laid on ice. Atropine, one to one hundred and twenty (1-120) p. r. n., i. e., from every thirty minutes to once daily. Also, employ any of the collyria mentioned through the lectures you may see indications for. As a result of one of the pre- viously desci'ibed inflammations, we may have : —
Granular Lids {Granular conjunctivitis, Granular ophthalmia. Trachoma). — Generally the result of one of the previously described inflammations, and is especi- ally a chronic condition, although sometimes associated with acute symptoms. The palpebral conjunctiva pre- sents almost exclusively the granulations, of which we have chiefly two kinds, to wit., enlarged conjunctival papillae and the frog-spawn granulations. These latter are grayish bodies resembling sago grains, ' and
68 VETEKINAKY OPHTHALMOLOGY.
are composed of lymphoid cells and connective tissue. Both varieties may be seen separately, but more often combined.
Symptoms are those of an annoying conjunctivitis, and may be more or less severe. If the process is not checked the cornea becomes ulcerated and vas- cular from the constant irritation from friction of the roughened lids upon it. The conjunctiva and tissue of the lids may become atrophied and cica- trical, leading to entropion, symblepharon, xerophthal- mia, etc. This disease is more often found in the poorly nourished, bad hygiene, etc. Runs an exceed- ingly tedious course.
Treatment. — Locally, astringents and caustics, sul- phate of copper crystal being the favorite one, nitrate of silver, alum, and many more. Applications may lose effect through toleration, and change becomes necessary, and regular treatment for a long period will be necessary to establish cure. Before beginning any astringent treatment of a trachoma, it may be necessary to use hot water, atropine, cocaine, until the great irri- tation, photophobia, etc., subside. Then may begin with a mild astringent, alum, spray of tannin and glycerine, XX. grs. to the oz. or the like. In very obstinate cases, after a fair trial with other remedies, jequirity bean {ahri(s precatorius\ used as follows, as prepared by De Wecker of Paris. The bean is to be powdered and mascerated for three hours, in water, at ordinary
VETERINARY OPHTHALMOLOGY.
59
temperature, and of a 3% concentration. The recent infusion is best,, as it loses power with age. With a camel's-hair pencil, it is applied to the lids, two or three times. Reaction should be present within twenty-four hours. If not, repeat application. This is painful in
Figr. 30.
action, and ice-water bags, etc., should be employed. The inflammation will last for at least two weeks. Keep patient in dark stall, and quiet. As soon as the inflammatory membrane has appeared, use the cold ap- plication until reaction has abated. Treat the case as
60 VETERINARY OPHTHALMOLOGY.
one of acute trachoma, when sulphate of copper crys- tal may be used until the cure is complete. When the granulations are large and numerous, they may be torn out and destroyed by forceps, and as this is a very delicate operation great care is to be exercised. The lid being everted, the granules are stripped off. As may be readily appreciated, the reaction is superb, and is to be carefully treated with ice, antiseptics, etc. To do this, an anaesthetic should be used. Now, in simple chronic blennorrhoea, or chronic conjunctivitis, do not use the above infusion. The results are apt to prove disastrous.
Phlyctenular Conjunctivitis. (Pimple, Gr.) — This form is characterized by a small yellowish-red eleva- tion, or phlyctenule, on the summit of which a serous vesicle forms, which vesicle bursts, and leaves a small ulcer. One or several of these bodies may be pres- ent, and are generally situated near the margin of the cornea. Duration about ten days ; but there always is great tendency to relapse. The injection of the con- junctiva may be general or partial. A triangular leash of vessels runs up to each phlyctenule, with its base pointing toward the retrotarsal fold. The appearance of the phlyctenule is attended by pain, which is burn- ing ; photophobia and lachrymation. Often associated with phlyctenular keratitis.
Treatment. — Particular attention is to be paid to the general condition. Atropine 1 to 120. In some cases,
VETERINARY OPHTHALMOLOGY. 61
application of a mild irritant, such as calomel or ox mercur}', ung., etc.
Xow for a word on dkir/nosis of a differential character. In catarrhal conjunctivitis, the injection is general over the conjunctiva, and on pressure, through tlie lower lid, the injected vessels are seen to move over the sclerotic with the membrane,, (i. e., the conjunctiva). There is tdtcays redness of the fornix conjunctiva, and usually of the palpebral ditto. There is a muco-purulent discharge, more or less profuse, dependent on degree. The iris is clear and bright, the pupil reacting readily to light, and the cornea is clear and transparent. In Iritis, the injec- tion is deep-seated, surrounding the cornea as a rosy zone. This is not accompanied by redness of the fornix, or palpebral conjunctiva. The injected ves- sels are beneath the conjunctiva, and do not move with it. The iris is discolored, the pupil sluggish and inactive, and vision is impaired. There is usually very severe pain in the eye and head, generally worse at night. In Trachoma, the upper lid, and particu- larly the free border of the tarsus, is affected; the granule is oval, grayish-red, and opaque. It is imbedded in the membrane, and is less prominent than the follicles. They may be found on the ocular con- junctiva, and even the cornea. In the granular variety, the affection usually takes on the mixed form, present- ing follicular and papillary hypertrophy in addition to
62
VETEEINAEY OPHTHALMOLOGY.
the new growth. There is also general lymphoid infil- tration of the conjunctiva and of the deeper tissues of the lid, including the tarsus, also great proliferation of epithelia and formation of new vessels. In papil- lary trachoma, the location is predominately over the surface of the tarsus, instead of its borders. The enlarged papillae are bright-red, or sometimes red with a bluish cast. Follicular Conjunctimtis espe- cially affects the lower lid, and particularly the cul- de-sac. The follicle is round, or elongated, pale and semi-transparent. Is more prominent and sharply raised above the surface of the conjunctiva, and can be removed or separated from it. Its general arrange- ment is in rows parallel to the free margin of the lids. Pterygium (a little wing, Gr.). — Quite a common
affection, result of in- flammation and from constant exposure. Consists of hypertro- phy of conjunctiva, and sub-conjunctival tissue. In form it is a triangular vascular prominence, general- ly at the nasal side of the eye, with the base toward the inner canthus and its rounded apex at the edge of the cornea, or encroaching more or less viyon the cornea. We notice two forms>
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 <tre no blood vessels. The anterior ciliary arteiies furnish branches, which approach the limbus, forming loops. Blood vessels on the cornea are indicative of either a pathological condition or an attempt of nature to repair. The nerves come from the ciliarj'-, which pass the ciliary body and form a plexus around the border of the cornea. Their terminal fibrillse are most abundant in the epithelium and anterior layers of the cornea. Some few twigs come from the con- junctival nerves.
Injuries and Wounds.— Many varieties — clean cut, -contused, scraped, etc. Clean cut, if not too large, usually heal and leave no trace. Contused wounds are apt to cause suppuration.
The great danger is of injury to the lens, which would be apt to result in cataract, or to the iris, which may prolapse, or, becoming adhered to the corneal puncture, cause staphyloma.
Treatment — The primary treatment is to place the eye in a state of rest and allay irritation by soothing applications. Atropine and cocaine should be applied several times daily ; atropine 1 to 120, or stronger if need be ; cocaine 4%. Cold compresses if seen early enough. If the epithelium is abraded a few drops of olive oil allays irritation. The compress bandage re-
68 VETERINARY OPHTHALMOLOGY.
strains motion and so is useful; also excludes lights If the corneal wound be central, use atroioine, and quick. If peripheral, eserine %%.
Foreign bodies are of frequent occurrence, the most common being dust, glass, metal, etc., and they cause severe reaction according to the depth to which they penetrate and length of time they remain. Ex- ceptionally, the reverse may be the case. They are seen easily, generally, and oblique illumination will facilitate a search. If superficial, remove with a spud. If firmly imbedded, use forceps or a needle. To avoid a deeply seated particle falling bacl-irards into the anterior chamber during attempts at removal, a broad needle may be passed into the anterior chamber so as to form a base on which to work. Cocaine 4% must be used, and an eye-speculum will insure better results if used.
Burns, injurie3, from chemical agents, etc., are apt to cause sloughing and permanent opacities. Use oil, cocaine ; wash the eye thoroughly, and neutralize acids by alkalis — for instance, soda, dram to the ounce. Should the offending matter be lime, use vinegar and water, oil, and, above all, don't put a little water into the eye.
Abrasions of epithelium appear as a roughened, glist- ening facet, and are very painful. Use oil collyria.
Keratitis (inflammation of the cornea.) Result of in- juriss, exposure, constitutional diseases, mal-nutrition>
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 0
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
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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 0 im