Prosthetic eye

“ Operation.—The patient recumbent, and the eye absolutely fixed by speculum and forceps, a linear incision, varying in length from one-sixth to one-fourth of an inch, is made just at the margin of the cornea. The point of election is the upper pole of the cornea. The lens must not be wounded. The best instrument for making the section is an ordinary linear extraction knife, bent at an angle to admit of its being introduced from above. The iris will protrude through the wound, or, if adherent, must be drawn out by forceps, and then is to be cut off with scissors. ”

“ In infants, where processes of repair go on very rapidly, the whole lens may be freely broken up. In diabetic cataract, or indeed in all cases of solution, where the patient is adolescent or adult, or the eye at all weak, only a small portion of the lens should be attacked at one sitting.
The needle should then be withdrawn gradually and with great care, that the broad axis of the blade be in exactly the same position in which it entered, i.e. flat and parallel with the iris, lest the iris be wounded, entangled, or prolapsed. ”

“ It can be resorted to only in adults, great steadiness on the part of the patient being absolutely necessary. The case, too, must be judiciously chosen. The conjunctiva must be sound, and indeed almost no operation on the eye should be undertaken unless this membrane is in a healthy condition; the cornea should be transparent in every part—the anterior chamber of a proper size—the pupil regular—the iris steady, and not protruded—and the cataract solid; there should be no rolling motion of the eyeball, and no adhesions of the iris. ”

“ From my own experience I should say, that both eyes ought not to be operated on at one time: if they are, there is great risk of violent inflammation being established, and of the operation failing to restore vision. Immediately after one eye has been operated on, the other becomes very unsteady, and is altogether in an unfavourable state for operation ”

“ In such circumstances the deformity may be remedied, after the parts have become quiet, by the adaptation of an artificial eye of enamel, made so as to resemble exactly the other eye. It is worn without inconvenience, removed at night like artificial teeth or a wig, and cleaned and replaced in the morning. Such a substitute is also useful when the humours have been evacuated, or the organ destroyed, by injury or the effects of inflammation. Too frequently the morbid growth is reproduced, and that rapidly. ”

“ The following method will assure one of success in nearly every instance. Failures are almost impossible. Punctures, perforations, tears, etc., are rare. The beginner should isolate the retina in about six to seven minutes; the expert in about four and a half to five minutes.
Select an eye with a long optic nerve, and prepare it for this dissection by placing it in a 10 per cent. solution of formaldehyde for [75] about ten to fourteen days, but no longer. If it is left in the hardening fluid longer than that length of time, it will interfere with the easy removal of the vitreous. ”

“ If the eye remain in a state of chronic disease and suffering, a similar incision will give the desired relief. If the chronic state of irritation affect the other eye, the incision and sinking of the ball of the one first affected or injured is urgently demanded, and should not be delayed. If the back part of the eye be left with the muscles attached to it, a stump remains, against which an artificial eye may be fitted, so as sometimes to render the loss of the natural one almost unobservable. ”

“ Continue cutting through the sclerotic and all underlying tissues, stopping at the corneo-scleral junction, but do not, during this procedure, [88] even touch the lens. After the eye has been thus partly separated into, as nearly as possible, two equal parts, lay it down upon the cornea, and, holding the razor blade in the forefingers and thumbs of both hands, cut the lens in two by forcing the blade down through it. (Fig. 42.) Partly open the cut eye to allow one jaw of the large scissors to enter, turn the eye over so the cornea will rest on that [89] jaw, and then cut through the cornea. ”

“ For the study of the interior of the eye and its contents in situ either a fresh or a hardened eye will do; a hardened eye is preferable. In the dissection for isolating the hyaloid membrane, vitreous, lens, and other parts, the anterior and posterior halves of the evacuated eye may be separated entirely, and each half studied. However, the choroid and the retina will be more or less mutilated, and the vitreous and other parts will be removed. ”

“ When a ball lodges behind the eye, it usually causes protrusion, inflammation, and suppuration of that organ. If it be not discovered by the usual means, its lodgment may be suspected from the gradual protrusion and inflammation of the eye itself. If it be discovered, it should be removed together with the eye, if such proceeding be necessary for its exposure. If suppuration have commenced in the eye, a deep incision into the organ will arrest, if not prevent, the horrible sufferings about to take place, and allow of the removal of the offending cause. ”

“ The large number of sensitive nervous filaments renders the visual organ very impressible to bodies that cause irritation, as dust, or intense light. This compels us to use due care to shield the eye from the influence of agents that would impair or destroy vision.
2d. Although particles of dust, when in contact with the delicate parts of the eye, induce severe pain, yet these parts may be cut in surgical operations, and the patient’s sufferings are not as great as when an incision is made in the skin to remove a small tumor. ”

“ Still another way to see the interior is to cut out a piece of the sclerotic about the size of a twenty-five-cent piece; then pinch up and tear out the choroid and the retina under the opening made in the sclerotic. (Fig. 57.) Hold the eye, the cornea forward, close to a bright light, and the image of the light will be seen upon the retina. The closer the light is to the eye, the greater the illumination will be in the [111] interior of the eye. If the opening or “window” is close enough to the optic nerve, the optic papilla can be seen easily. ”

“ In opening the capsule care should be taken not to separate its attachments, otherwise it will become opaque, and thereby passage of light to the bottom of the eye will be again obstructed. Neither should much pressure be used for extrusion of the lens; for, in the case of a large and firm cataract, the iris may be lacerated, and the humours escape. When any of the vitreous humour has escaped, in consequence of its cells having been broken down, and its tenacity diminished, the eye soon fills again, but good vision is hardly to be expected. ”

“ The cause is found in some [pg 385] difference in curvature of the surfaces of the cornea or crystalline lens. It is corrected by lenses so ground as to correct the particular defects present in a given eye.
Whenever defects in focusing are present, particularly in astigmatism, extra work is thrown on the ciliary muscle as well as the muscles that move the eyeballs. The result is frequently to induce a condition, known as muscle weakness, which renders it difficult to use the eyes. Even after the defect in focusing has been remedied, the muscles recover slowly and must be used with care. ”

“ Notice the thinness of the retina, and, also, that the seeming iridescence of the choroid shows through. The optic disc, which is the point of entrance of the optic nerve, and the optic cup are easily recognized, though neither will be seen as large as when viewed in the living eye with an ophthalmoscope. The blood vessels of the retina, as they ramify outward or forward, after their entrance through the optic nerve through which they pass, are also very plainly seen. ”

“ The aqueous humour is either secreted in greater abundance than it usually is, or absorption is diminished. The cornea gradually accommodates itself to the increase of the fluid behind, and becomes wider and more prominent, but retains its transparency; in looking at the eye, the anterior chamber is seen evidently enlarged, and occasionally the aqueous humour is of a turbid appearance. There is little or no pain in the eyeball, but the patient complains of an annoying sense of fulness and tension in the part. ”

“ In the human eye an attempt is made to apply all these methods, but the most important is the third, that of applying the diaphragm formed by the iris, a circular semi-muscular curtain lying just in front of the anterior surface of the lens. The iris is also furnished with a layer of pigmental cells which effectually stop out all peripheral rays of light that otherwise would pass into the eye, creating circles of diffusion of a disturbing nature to perfect vision. ”

“ The cornea of the right eye is rapidly becoming transparent. The convexity of the left eye is still considerable, but the opacity is so far removed as to give evidence that a continuation of the medicine will render it again perfect, although it must take a considerable time to effect so desirable an object. ”

“ The incision. The position of the surgeon is as for cataract extraction. The eye is fixed by grasping the conjunctiva close to the limbus downwards and inwards. If the patient be under an anæsthetic, two pairs of fixation forceps should be used, one being held by an assistant. Occasionally in glaucoma the conjunctiva tears very easily, and in these cases scleral forceps are of use, or, if the knife be already in the eye, grasping the insertion of the superior or inferior rectus. ”

“ Now we shall discourse on the curative treatment of eye-diseases which require surgical incisions (Bhedya-Roga-Pratishedha) . 1.
Treatment of Visa-granthi:— In a case of suppurating Visa-grauthi, it should be first fomented, and its puncture-like holes should be completely incised (so as to remove any swelling in the affected part) . It should then be dusted with Saindhava, Kâśiśa, Mâgadhi, Pushpânjana, Manah-śilâ and Elá pounded together*. ”

“ The room is made perfectly dark; a brilliant light is then placed near the head of the patient, and the rays are reflected by a series of small mirrors into his eye, as if they came from the eye of the observer; then, by looking through the central aperture of the instrument, the oculist can examine the illuminated interior of the eyeball, and perceive every detail of structure, healthy or morbid, as accurately and clearly as we can see any part of the exterior of the body. ”

“ In inflammation of the external parts of the eye, the redness begins from the margins of the organ, and gradually diffuses itself towards the cornea. Such is not the case in inflammation more deeply seated. There is intolerance of light in a slight degree, and the patient is inclined to keep the eyelids shut. At first the discharge from the conjunctiva and meibomian glands is increased and changed, and flows occasionally over the cheek, producing a scalding sensation. When the eyelids are at rest, as during the night, they become glued together by the viscid fluid from the meibomian follicles ”

“ Iris forceps are made with blades of varying degrees of curvature; the surfaces near the points may be roughened or smooth; or the points may be toothed.
The points of the forceps used for fixing the eyeball during operation should be toothed. Each tooth should be sharp, and almost in a line with the blade, if the forceps are used for grasping the sclerotic. ”

“ The procedure may be facilitated if the patient is instructed to look down while the operator is drawing the eye-lid upward.
If the particle cannot be easily removed by any of the above methods it is not safe for an uninstructed individual to go any further. The eye is an exceedingly delicate organ and may be permanently injured by unnecessary irritation. It is always safer and it may be cheaper in the long run to consult a competent oculist in such cases. ”

“ Deformity may be in a great measure removed by adapting an artificial272 eye to the shrivelled remains of the natural one. When it is necessary to remove only a small part of the cornea, the aqueous humour alone escapes, and during the cure of the wound the patient not unfrequently enjoys a tolerable degree of vision ”

“ The human eye was evolved to satisfy the demands of ordinary vision—that is, to make on the average 15 or 20 movements per minute, under conditions which permit frequent shifts of accommodation and convergence. The work of the school demands of the immature eye that it execute for several hours a day an average of 150 to 200 separate movements per minute with as many rifle-aim fixations and with a uniformly intense strain of the muscles of accommodation and convergence. What is the relative importance of these factors as compared with heredity in the etiology of ocular defects? ”

“ In either case the eyeball is protruded, and the cornea is exposed to irritation and may become inflamed and ulcerated. The optic nerve may be lacerated, and complete and permanent loss of vision result. Sometimes the ocular muscles and nerves are damaged, and deviation of the eye or loss of motion in one or other direction results. The globe itself may be injured. Foreign bodies lodged in the orbit, so long as they are aseptic, may give rise to little or no disturbance, and are liable to be overlooked. The Röntgen rays are useful in determining the presence and position of a foreign body. ”

“ The editor is practically alone in advocating central fixation. A small number of physicians, including a few eye specialists, who have been cured or seen members of their families cured of eye troubles, without glasses, operations, or medication, have been convinced that the old theories about the eye and the treatment of defects of vision are wrong ”