Complete Text (Part 6)

cornea. It has been the practice of some operators to use the crystal of the sulphate of cop- per in these cases, applying it directly to the corneal surface. What is suppurative keratitis? Suppurative keratitis is a term employed to designate a condition of the cornea in which there is a loss of substance from ulcerative processes and the formation of pus between the lamellae of the cornea, which fre- quently finds its way into the anterior chamber. When suppurative keratitis is extensive it produces a condition of softening of the cornea known as keratitis malacia. Many authors describe a condition of abscess of the cornea. It is, however, doubtful whether true abscess of the cornea ever exists. Probably some opening to the surface is present in all these cases. THE CORNEA. 49 What are the causes of suppurative keratitis? This is usually due to the inception of some infectious material, as wound of the cornea by the finger-nail, a piece of oyster-shell, a stalk of hay, or some germ-carrying object. These cases are of rather fre- quent occurrence among farmers and fish-dealers. What is the treatment of suppurative keratitis ? The treatment of this condition is, on the whole, rather unsatisfactory. Antiseptic lotions — principal among which is the bichloride of mercury — should be used freely to promote as thorough disinfection of the parts as is possible. Atropine should be employed to prevent iritic adhesions, as in this form of keratitis iritis is a frequent complication. If the pus has entered the anterior chamber and is there accumulating — a condition known as hypopyon' keratitis — a free paracentesis should be performed, permitting of the escape of pus, and the anterior chamber should be washed out as thoroughly as possible either with a very weak solution of the bichloride of mercury or a solution of boric acid. What is ulcerative keratitis? The term is one given to designate the loss of corneal tissue from all causes aside from traumatism. (An injury to the cornea produces a su- perficial defect in the corneal tissue, the walls of which are usually clean. This is known as simple traumatic ulcer of the cornea. ) If the walls of a corneal defect are clear, the condition is known as simple ulcer of the cornea. When the walls of the defect assume a grayish appearance and the gray infiltration extends into the corneal tissue, the condition is known as one of infiltrative or infectious ulcer of the cornea. In some cases the grayish infiltration, with a defect in corneal tissue, appears at the margin of the cornea, extending along its periphery. The shape of this ulcer causes it to be known as a crescentic ulcer of the cornea. In other cases a grayish infiltration appears in the corneal tissue immedi- ately beneath the epithelium, extending in zigzag lines over a portion of the cornea, causing loss of epithelium eventually in all parts of its course. Its shape gives it the name of serpent ulcer of the cornea. Ulcers are also known as superficial or deep according as they affect the superficial or deep layers. What are the symptoms of ulcer of the cornea ? In advancing ulceration of the cornea pain, referable to the eye and to the parts subjacent, is more or less intense, usually being more severe when the superficial layers of the cornea, the epithelium in particular, are being destroyed. Photophobia is a marked symptom. The iris is frequently involved, and, when it is, pain, referable to the side of the head, is a prominent feature. The patient is unable to use his eyes. What is the treatment of ulcerative keratitis ? In the early stage of infected ulcer, when but little destruction of tis- sue has ensued, it is advisable to destroy all of the tissue involved by use 4— Eye 50 THE EYE. of the galvanic cautery. In cases where this is not applicable, frequent instillation of an antiseptic lotion should be used, in connection with atropine, to prevent adhesions between iris and lens. In cases where pus enters the anterior chamber and shows a tendency to accumulate, paracentesis of the anterior chamber is advisable. What is meant by the term "onyx" in ulcer of the cornea? When pus is produced, accompanying ulceration of the cornea, it sometimes occurs that the pus infiltrates between the lamellae of the cornea, and, gravitating to its most dependent portion, forms a patch in appearance somewhat like the lunule at the base of the finger-nail. This has given the condition the name of ' ' onyx. ' ' What is meant by the term "hypopyon keratitis"? When in ulceration of the cornea pus has found its way into the ante- rior chamber, or when during iritis a purulent deposit is formed in the lower part of the anterior chamber, the Fig. 8. condition is termed hypopyon. In the treatment of ulcers of the cornea where hypopyon exists it often becomes advis- able to make an incision through the cornea, forming paracentesis, for the purpose of evacuating the pus (Fig. 8). The operation devised by Samisch is also applicable in these cases. It con- sists in making a free incision, usually through the ulcer, and evacuating the puro-lymph contained in the anterior chamber. What are some of the results of ulcerative and suppurative kera- titis? Following ulcerative keratitis as a di- rect result, perforation of the cornea not infrequently occurs. The anterior cham- ber is evacuated, the iris is pushed for- ward into the opening, and in some cases where the loss of corneal substance is ex- tensive, the lens capsule is ruptured and the lens escapes. As the suppurative process runs its course and is in process of healing, the opening gradually closes by the formation of cicatricial tissue, and an opacity takes the place of the site of the ulcer. Where perforation has en- sued there is, in the majority of cases, an inclusion of the iris in the — Abscess. Wm. .. Onyx. Vertical Section through Anterior Part of Globe (diagrammatic). THE CORNEA. 51 cicatrix following. The opacity resulting from ulceration without incar- ceration of the iris is known as simple leucoma. Where the iris is in- cluded in the cicatrix the condition is known as adherent leucoma, and the iritic adhesion to the cornea produces the condition of anterior syn- echia, which may be partial or complete. Following the ulcerative or suppurative processes in the cornea we may have cicatricial formations, including almost the entire cornea. The new-formed tissue often pre- sents insufficient resistance to the intraocular tension, and bulges in the weak parts, forming what is known as staphyloma of the cornea. This is known as partial when but part of the cornea is involved, and is com- plete when the whole cornea bulges forward. What is the treatment of leucoma of the cornea ? In the early formation of leucoma some benefit may be derived from the employment of various agencies for promoting the clearing up of the opacity. Hot fomentations, and at times the application of calomel or of ointments, may be of some benefit. When the leucoma is of long standing but little can be done to reduce the opacity in extent or density. Where the centre of the pupil is covered by the cicatricial tissue, if some clear portion of the cornea remains, vision can usually be greatly im- proved by the making of an iridectomy in the portion corresponding to greatest corneal transparency. This applies as well to simple as to adherent leucoma. In certain cases of adherent leucoma symptoms of glaucoma supervene which will be relieved only by the making of an iridectomy. How is the operation of iridectomy performed ? The operation may be done with cocaine anaesthesia, but, because of some pain which almost always accompanies the operation when cocaine alone is used, ether must be given in a certain portion of the cases. The patient is placed either in an operating chair or on the table, the operator standing behind the patient's head. The eye and surrounding parts are thoroughly cleansed by washing the skin with soap and water, and the skin and conjunctival sac with an antiseptic solution, preferably solution of bichloride of mercury, 1 : 5000 or 1 : 10,000. A stop speculum is then in- troduced between the lids. An incision is then made through the cornea, after fixing the eye with fixation forceps, either with the keratome or Graefe knife, usually a little back of the clear margin of the cornea at the point selected. Care must be taken not to wound the iris or lens. The fixation forceps are then transferred to an assistant, and the curved iris forceps introduced through the wound into the anterior chamber with the blades closed. The blades are then permitted to open, and a firm hold is taken on the iris near its free margin. It is then gently withdrawn and a piece cut off with a small iris scissors. The remnant of the iris is then restored to the anterior chamber by means of a small spatula, the margins of the wound adjusted, the speculum removed, and 52 THE EYE. the eye bandaged. Recovery from such an operation takes place in from five to ten days. What is the treatment for staphyloma of the cornea ? When staphyloma is in its very early stage, and is partial, it may be frequently aborted by means of iridectomy. In the advanced stage, or when it involves nearly all of the cornea, iridectomy is of no avail. The protrusion must then be excised or the eye enucleated. Excision of the staphyloma is done in various ways by different operators. A common method is to pierce the staphyloma at its base with a Graefe knife, and cut it off at the sclero-corneal margin. Before the protrusion is excised sutures are so placed through the conjunctiva and episcleral tissue that the opening may be somewhat closed afterward. The lens is usually evac- uated and the sutures tied. After such an operation healing takes place gradually, and a shrunken stump is the result, suitable, however, to bear an artificial eye. What is the operation for tattooing the cornea? This consists in changing the color of the scar-tissue from white to black in the portion corresponding to the pupil. It is performed under anaesthesia with cocaine. A stop speculum is introduced, and india ink in the form of fine powder or a thick paste is spread over the part to be colored. Then with an instrument consisting of a number of needles placed closely together the cornea is punctured in an oblique direction over the area to be tinted. This process is continued until the desired degree of color is obtained. At times it is necessary to repeat the opera- tion. The reaction attendant upon this operation is usually slight. In some cases it is quite severe. The operation, however, is comparatively harmless. It is done for the cosmetic effect only. What deposits take place in the corneal tissue ? Metallic and chalky deposits. The metallic deposits usually observed are those of the carbonate of lead, which forms a white, densely-opaque mass. It results from the employment of solutions of the acetate of lead in the eye when ulcer of the cornea is present, A deposit of chloride of silver is sometimes formed as a result of the use of strong solutions or the crystal of nitrate of silver in treating corneal ulcers, followed by the instillation of solutions of the bichloride of mercury. In some cases of chronic superficial keratitis observed in trachoma chalky deposits are found. In the form of keratitis known as "ribbon- shaped keratitis ' ' chalky deposits are frequently present, What is the treatment of deposits in the cornea ? The most favorable results are obtained by scraping and by excision. The eye is anaesthetized with cocaine, the lids held apart by a speculum, and the cornea scraped by means of a small, sharp curette. The deposit is carefully removed and a compress bandage placed over the eye. Excision THE CORNEA. 53 of the deposit is effected by the use of a Beers or of a cataract knife. The knife is passed through the superficial layers of the cornea beneath the deposit and the deposit carefully excised. Atropine is instilled and the eye bandaged. Healing usually progresses rapidly. What is conical cornea? It consists in the bulging forward of the central portion of the cornea, forming a cone the base of which corresponds to the periphery of the cornea, the apex to the centre of the cornea. The cone is transparent. A high degree of myopia in the centre of the cornea is produced by this condition. What is the treatment of conical cornea ? Because of the conical shape of the cornea vision is very imperfect, and it is difficult to adjust glasses that will be of much benefit to the patient. It is therefore desirable to restore the normal curvature of the cornea. Various methods of operating have been devised for this pur- pose. An operation which has given beneficial results is that of remov- ing a small circular piece of corneal tissue from the apex by the use of a small trephine. After the piece has been punched out the cornea heals with a small central cicatrix, and the conical curve of the cornea is very much reduced. This operation was devised by Bowman. Another ope- ration is to excise an oval piece of the cornea at the apex. This is also attended with very good results. Other operators have succeeded by the use of the galyano-cautery in cauterizing the apex of the cone, with good results in the improvement of vision. What forms of tumor is the cornea subject to? Epithelioma, sarcoma, and dermoid tumors are sometimes met with on the cornea. The form of epithelioma closely resembles that met with in other parts of the body. Sarcoma, when it exists, is usually subse- quent to sarcoma in other parts of the eye or is communicated from the lids or orbital tissues. Dermoid tumors are congenital in their origin, presenting the ordinary tissues of dermoid tumors in other parts of the body ; that is, they present the formation of skin by hair-follicles and glands, and are sometimes pigmented. What is the treatment of tumors of the cornea ? Excision should be employed where practical. In cases of epithelioma it is advisable to cauterize the base of the tumor after thorough excision has been practised. What is the treatment of lacerated wounds of the cornea ? As a rule, in lacerated, non-perforating wounds of the cornea all that is required is careful cleansing of the eye and the application of a pro- tective bandage. In some cases where iritis is feared it is advisable to instil atropine into the eye. In perforating wounds the iris is frequently involved. It prolapses or is incarcerated in the wound. Excision of the 54 THE EYE. protruding part of the membrane should be practised in every recent case. Atropine should be instilled, the margins of the wound adjusted as perfectly as possible, and after thorough cleansing with an antiseptic solution a compressed bandage should be applied. Are foreign bodies in the cornea met with? They are, and are of very frequent occurrence and of all varieties. Particles of coal and iron are most frequent. How are foreign bodies in the cornea detected? The patient often comes with the complaint that he has a foreign body under the upper lid. In all such cases, if on eversion of the upper lid the foreign body is not discovered, the cornea should be carefully exam- ined by the use of the oblique method. The minutest particles can be detected in this manner and their removal effected. What is the treatment of foreign bodies in the cornea ? The offending particles should be removed at the earliest possible time. A drop of cocaine is instilled, and after the cornea has become anaes- thetic the particle is raised from its bed by the use of a spud or of a foreign-body needle, the surfaces of the depression produced thoroughly cleansed, and a solution given with which to keep the eye in an aseptic condition until the wound produced by the foreign body and by the efforts in its removal has healed. What forms of burns of the cornea are met with ? Burns by powder, by acids, by lime and other alkalies are not uncom- mon. Burns by powder often produce defects which interfere with vis- ion, but the presence of the remains of powder-grains in the cornea are of no particular danger or significance except when they occupy the pupillary area. Burns with acids leave usually but little opacity. Burns from quicklime and from other alkalies are very apt to cause dense opa- cities, which even without destruction of the cornea make vision almost impossible. The opacity produced by lime usually becomes much more dense some weeks after the injury has been received than is evident at the time or a few days afterward. The entrance of molten lead or iron into the conjunctival sac frequently produces but little injurious result. What is the treatment of burns of the cornea ? In burns from powder as much of the substance of the powder-grains as possible should be removed. The use of a boric-acid solution to pre- vent infection should be employed. Healing under these conditions usually progresses favorably. In the case of a recent inception of acid the conjunctival sac and corneal surface should be thoroughly washed with some alkaline _ solution : a solution of bicarbonate of sodium is very excellent for this purpose. In the case of the inception of ammo- nia the eye should be well washed out with clean water to which a very few drops of acetic acid or of vinegar are added. In burns from THE SCLEEOTIC.