Complete Text (Part 5)

produce favorabie results. What is pterygium ? Pterygium is a condition of hypertrophy of the conjunctiva occurring usually at the inner side of the cornea, and often encroaching upon it to such an extent as to almost entirely cover the pupil. It is wedge-shaped, the apex being directed to the cornea, its base corresponding to the caruncle. What is the cause of pterygium ? _ Pterygium is undoubtedly due to long-continued irritation of that por- tion of the conjunctiva which is most commonly exposed to infection from without — namely, that portion opposite the palpebral fissure. It springs usually from a preceding pinguicula and extends forward on to the cornea. It is most common in men, occurs always on the inner side of the cornea at first, and may subsequently appear on the temporal side. 42 THE EYE. What is the treatment of pterygium ? This consists in excision. A number of methods for the removal of pterygium are in vogue. Simple excision is performed as follows : The pterygium is grasped by the fixation forceps at a point about two lines from the margin of the cornea ; a knife — usually a Beers cataract knife — is made to pass beneath the tissue of the pterygium with the cutting- edge directed toward the cornea. The pterygium is then carefully dis- sected from the cornea, often a thin piece of the corneal tissue being re- moved with it. With the scissors a wedge-shaped piece of the subjacent hypertrophied tissue is then dissected off, its apex reaching the caruncle and its base being near the cornea. The conjunctival edges of the wound are then brought into apposition by the use of sutures, a compressed bandage is applied, and the patient dismissed. Healing occurs rapidly. The method of transplantation is largely employed. It is performed as follows : The apex of the pterygium is dissected from the cornea as above. An incision is then made through the ocular conjunctiva from the first wound into the lower cul-de-sac. The point of the pterygium is turned downward into this incision and stitched into the lower cul-de- sac. The margins of the wound are then brought into apposition. What is a pinguicula? A pinguicula is a little yellowish elevated mass which appears in the horizontal meridian of the globe to the nasal side of the cornea, situated in the conjunctivae, usually about two lines from the free margin of the cornea. It is made up of connective tissue, elastic and non-elastic. It is usually the forerunner of pterygium, but calls for no special treat- ment. What is amyloid degeneration of the conjunctiva ? This rare form of disease of the conjunctiva consists in the develop- ment of translucent swellings appearing in the conjunctival tissue, the ocular conjunctiva being first affected. They consist of corpuscles and trabecular, with numerous nuclei in a liquid matrix contained in a lim- iting membrane ; the corpuscles and trabecule give a strong amyloid reaction to iodine and sulphuric acid. The condition is local and unac- companied by pain. What is xerosis of the conjunctiva ? Xerosis of the conjunctiva is of two varieties : First, that form of dryness of the conjunctiva resulting from atrophy following trachoma. The cornea becomes cloudy and opaque and vision is much interfered with. In the second form complete dryness is not present. This condi- tion appears usually in poorly-nourished individuals, and is characterized by the occurrence on the conjunctiva of white foamy masses of an oleagi- nous or greasy nature. The patches appear in adults as small triangular masses at the margin of the cornea in the horizontal meridian, and the disease has been given the name of xerosis triangularis because of the THE CONJUNCTIVA. 4d form assumed. In infants the foamy masses usually first appear in the folds of the lower cul-de-sac, and as the disease progresses it covers the whole conjunctiva. In infants it is known as xerosis infantilis. It always affects infants with marasmus, and appears always to end fatally. In the adult the disease is frequently accompanied hy night-blindness. What are the causes of xerosis.? It was supposed by Graefe that the disease was dependent on a cere- britis, particularly in infants, and this view was partly confirmed by re- searches into the condition of the brain conducted by Virchow. Later writers have recognized the association of bad food; confinement, and bad hygienic surroundings in this disease, and claim it to be dependent upon these and on mal-assimilation of food. Laber described a bacillus which is constantly found in the frothy secretion, and which he claims to be the pathogenic principle. This claim has not been verified by others. It is now generally believed that the condition of the tissues favors the growth of this micro-organism, and that it would not exist if the system were restored to the normal condition. What is the treatment for xerosis? When occurring in infants treatment is of little avail. In adults, since the secretion is of an oily nature, saponifying remedies should be em- ployed to cleanse the affected portions. Applications of strong antisep- tics may then be made, either in watery or in oleaginous menstrua. The thickened mass is first scraped away, the saponifying remedy applied, and the antiseptic used subsequently. Recovery is slow, but may be much hastened by change of air and of diet. What is subconjunctival hemorrhage? As the name implies, it is the escape of blood beneath the conjunctiva. It usually occurs beneath the ocular conjunctiva as the result of a blow or of strain in coughing or at stool, or from some violent exercise. It produces a peculiar deep-red patch, which may partly or wholly surround the cornea. The treatment is expectant, and by the use of hot applications to hasten absorption. What is tuberculosis of the conjunctiva ? Tubercular infection of the conjunctiva is of rare occurrence. It is not infrequently termed lupus, and is probably identical with that condi- tion. Direct infection of the conjunctiva may occur, but it more fre- quently happens that the disease is communicated to the conjunctiva by way of the lachrymal passages from the nose in tuberculosis of the nasal mucous membrane. In the early stage isolated nodules resembling tra- choma-follicles appear usually upon the palpebral conjunctiva, but also at times on the ocular. These nodules break down and form superficial ulcers. The disease advances slowly. 44 THE EYE. Excision and the use of the galvano-cautery are the means employed in the treatment of this condition. THE CORNEA. What is the structure of the^cornea ? The cornea is a clear, transparent membrane forming a portion of the anterior segment of the fibrous coat of the eye. Its radius of curvature is shorter than that of the sclerotic, and the cornea consequently extends a little in advance of the curvature of the sclerotic. It is composed, from without inward, of an epithelium layer of the stratified variety placed on a basement membrane known as Bowman's membrane. Bow- man's membrane is a thin, finely fibrillar layer which under ordinary powers of the microscope appears homogeneous. These two layers are continuous with the conjunctiva. Beneath Bowman's membrane is the substancia propria of the cornea. This is much the thickest layer of the cornea, and consists of bundles of connective tissue arranged in lamellae placed parallel to the surface of the cornea. These lamellae are bound together by a cement-substance. Penetrating the cement-substance in every direction are small canals, presenting at their intersections spaces known as lacunae. This system is known as the canalicular lymph-system of Recklinghausen. They afford opportunity for the passage of the nutrient fluids from the periphery to all parts of the corneal tissue. The lacunae give lodgment to large branching cells, the fixed cells of the cor- nea, Each cell occupies but a portion of a lacuna. The branches of , the cell pass into the small canals and anastomose with branches from adjoining cells. The lymph-spaces also give passage to the nerve-fila- ments. The substantia propria of the cornea passes into the sclerotic. Posterior to the substantia propria is the thin homogeneous elastic mem- brane known as Descemet's membrane. This membrane is lined poste- riorly by a single layer of hexagonal cells, the endothelium of the cornea. Descemet's membrane breaks up at the periphery of the cornea into the ligamentum pectinarum. This ligament passes back to the cil- iary body and forms a portion of the root of the iris. The spaces be- tween the meshes of the ligamentum peetinatum are lymph-spaces, and are in free communication with the lymph-system of the cornea. The cornea is devoid of vessels, but is very rich in nerves. Its nerve-supply is derived from the ciliary nerves. The nerve-trunks, twenty or thirty in number, pass into the cornea from the periphery into its deeper layers. where they form a plexus from which the radial bundles pass toward the surface of the cornea, breaking up into a finer plexus at the base of the epithelial layer. From this plexus the terminal filaments pass upward into the epithelium. What is meant by the method of examining the cornea by oblique illumination? This method, which affords the best means of examining the cornea, THE COENEA. 45 is conducted as follows : The source of light, an Argand burner, candle, or incandescent lamp, is placed slightly in front of the patient and to the side, at a distance of 1 metre and at an angle of about 35° to the plane of the face, and about on a_ level with the eyes. A lense having a focal distance of about 3 inches is interposed between the source of light and the cornea to be examined, in such a way as to focus the light on the Fig. 6. Focal Illumination. part to be examined. The observer places himself in front of the pa- tient, aad by focusing the light as above described is enabled to deter- mine with great distinctness the condition of the cornea in all its parts. This method of examination is also applicable to the iris and lens. What inflammatory conditions is the cornea subject to? Superficial, parenchymatous, phlyctenular, vascular, suppurative, and ulcerative keratitis. What is superficial keratitis? This form of inflammation of the cornea is frequently dependent on the presence of some irritating substance in the lids or on the friction of 46 THE EYE. the roughened lids against the cornea. It affects, as the name implies, only the superficial layers, and is usually of transient duration. There is a form of superficial keratitis which, beginning at the periphery of the cornea as a shallow depression with a whitish margin, advances over the cornea in its superficial layers, progressing slowly, causing some pain and much photophobia, and gradually involving the greater part of the sur- face of the cornea. This form of keratitis is undoubtedly due to infection. What is the treatment of superficial keratitis? Where the cause can be ascertained it should be removed. Bathing of the eye with a solution of boric acid and the instillation of a solution of the bichloride of mercury. 1 : 10,000, every two or three hours, com- bined with the use of a solution of atropine in cases where iritis threat- ens, will usually suffice to promote a cure. In individuals of low vitality. tonics, and possibly change of air. must also be advised. What is parenchymatous keratitis ? This condition consists in infiltration of the deep layers of the cornea with small cells, producing more or less marked opacification of the cor- nea without passing on to the production of pus. What are the symptoms of parenchymatous keratitis ? The patient experiences slight pain at the outset, with marked dread of light. Vision becomes impaired. At first a very thin grayish film may be detected in the deeper layers of the cornea by examination with oblique illumination. This opacification increases gradually, remaining of a whitish, pearly tint in the mild cases, becoming dense and yellowish in severer cases. Examination with the magnifying-glass shows the cornea to be traversed by minute blood-vessels. In certain cases the vascularity is sufficiently marked to produce the so-called salmon patches of the cornea. The disease is very slow in its nature, requiring from six months to a year and a half to run its course. Some residue of the opacity is almost always left. and. in the cases where dense opacification includes the whole cornea, vision is permanently much impaired. What are the causes of interstitial or parenchymatous keratitis ? This disease owes its origin in almost every case to inherited syphilis, as has been clearly and forcibly demonstrated by Jonathan Hutchinson. In some cases heredity cannot be traced, but it probably exists. ^ There are associated with this condition certain characteristic signs in other parts that go to complete the picture. The face is usually narrow in its lower half, the skin wrinkled, and the lips drawn or puckered. On ex- amining the teeth a peculiar condition is apt to be found. The upper incisors are generally the ones most affected. They are narrow, placed apart from each other, round, peg-shaped, and notched at their extrem- ities. Often the teeth decay early in life and stumps only remain. The palatine arch is frequently narrow and deep. Enlargement of the cervi- cal and submaxillary lymphatic glands is often noticed. Parenchymatous THE CORNEA. 47 keratitis is most frequently observed in childhood between the ages of eight and fifteen, but may occur much earlier, and has been observed as Fig. 7. OC Syphilitic Teeth. late as the thirty-fifth year. Although almost always due to hereditary syphilis, rare instances are on record of its occuring in individuals who have had primary, sores. What is the treatment of parenchymatous keratitis ? The treatment is local and general. The local treatment consists in the use of atropine and bathing of the eyes in hot water. They should be protected from bright light to prevent the annoyance that light occa- sions. This may be done by the use of dark glasses or by keeping the patient in a darkened room. The ointment of the yellow oxide of mercury may be introduced into the eye from time to time with beneficial results. It is a recognized fact that wherever vascularity can be induced the gray- ish patches will clear up to the greatest extent. The object of the treat- ment is therefore to stimulate the development of vessels in all portions of the cornea. The internal treatment should consist in the adminis- tration of mercury and of iodide of potassium in small, continued doses. Cod-liver oil and the syrup of the iodide of iron will be found valuable, taken internally, in their effect on the general system. What is phlyctenular keratitis ? Phlyctenular keratitis resembles very closely the affection by that name which occurs in the conjunctiva. The phlyctenule first appear on the cornea in the shape of small elevated vesicles, usually connected with the conjunctiva by a number of minute vessels. As the disease pro- gresses the vesicles are found to contain pus, and break down and form small ulcers. This affection in the cornea is quite painful and produces marked photophobia. In certain cases after a vesicle has broken down another appears, slightly in advance of the first, being also connected with the periphery by a leash of small vessels. This process may continue until a narrow path has been formed across the cornea. The process may stop short at any point, but leaves a whitish line to mark its track. Phlyctenular keratitis is not identical with herpes of the cornea. What are the causes of phlyctenular keratitis ? The same causes are at work in the production of phlyctenular kera- titis as are instrumental in the production of phlyctenular conjunctivitis. It is analogous to eczema of the skin, and is termed by some authors eczema of the cornea. 48 THE EYE. What is the treatment of phlyctenular keratitis ? It occurs usually in children whose general condition is somewhat run down. Tonics should be employed, in connection with good food and good sanitary surroundings, to build up the health of the individual. Frequent bathing with a mild antiseptic solution and the introduction of the yellow-oxide-of-mercury ointment into the eye once or twice daily will suffice to promote a cure. In cases where deep ulcers of the cornea exist atropine may be employed with benefit. What is vascular keratitis ? Vascular keratitis, frequently termed pannus, usually accompanies trachoma, and is the result of friction on the cornea by the roughened lids. The vascularity affects the superficial layers of the cornea. Ves- sels appear, advancing from the periphery, and pass just beneath the epithelium, rendering it uneven. These increase rapidly in number, and may eventually form a red, fleshy-appearing surface over the entire cornea. Vision is very much impaired, and in some cases almost com- pletely abolished. Frequently the vascularity will disappear if the rough- ness of the lids is corrected. In many cases not a trace of the previous vascularity can be determined, but in the majority of cases a residue re- mains which permanently interferes with vision. What is the treatment of vascular keratitis ? Removal of the cause which has produced the vascularity will, in the greater number of cases, suffice to bring about a cure. In severe cases an operation may be performed which has for its object the cutting off of the blood-supply to the vessels on the cornea. This operation is known as peritomy or syndectomy. It consists in dissecting up a narrow strip of the conjunctival and subjunctival tissue about the whole circumference of the cornea. Instead of dissecting, the galvano-cautery may be em- ployed for the same purpose. _ The narrow electrode may be passed entirely round the cornea, burning sufficiently deep to destroy all vessels that pass on to the corneal surface. These operations suffice to aid materially in clearing up dense vascularity of the