Opthalmia

“ But human beings are often called to still greater trials—to total loss of sight—in other words, to perfect blindness. This calamity results from many causes; for example, the cornea may become so opaque as to be incapable of transmitting rays of light into the interior chamber of the eye; or the crystalline lens, also, may become opaque (cataract;) disease of the iris, attended by closure of the pupil, will produce blindness, as will also paralysis, or loss of energy, in the retina or optic nerve, (Amaurosis or Gutta serena.) ”

“ A characteristic of this condition is increase of the intra-ocular tension, which has a deleterious effect on the optic nerve end and its ramifications in the retina. The cause of the rise of tension is partly congestive, partly mechanical. The effect of glaucoma, when untreated, is to cause ever-increasing loss of sight, although the time occupied by the process before it leads to complete blindness varies within such extraordinary wide limits as from a few hours to many years. ”

“ Here the eye, as an optical apparatus, remains passive. Just as a man, who sees, is aware of the phenomena even in the deepest darkness, so is also a blind man, as long as the retina is endowed with its specific sensitiveness or sensory power, by which it responds to every irritation with a luminous sensation. Even after blindness, this dancing of sparks of fire and light may be kept up by continual irritation in the eye to such a tormenting extent, that, in order to prevent it, we usually cut the optic nerve just behind the eye, when the sparkling and scintillating cease. ”

“ The opacities in the cornea or aqueous, in front of the axis of vision in the lens move in the same direction and to the same degree as the eye rolls, while opacities on the posterior capsule or in the vitreous, move in a direction opposite to the motions of the eye, and to a degree corresponding to their distance back of the lens. Thus if the eye looks downward such opacities move upward; if it looks upward they move downward; if it looks inward they move outward; and if it looks outward they move inward. ”

“ When the eye is inflamed, great light becomes eminently painful, owing to the increased irritative motions of the retina, and the consequent increased sensation. Thus when the eye is dazzled with sudden light, the pain is not owing to the motion of the iris; for it is the contraction of the iris, which relieves the pain from sudden light; but to the too violent contractions of the moving fibres, which constitute the extremities of the optic nerve. ”

“ The shifting of the eye with normal vision is usually not conspicuous, but by direct examination with the opthalmoscope.* When the optic nerve is observed with the ophthalmoscope, movement can be noted that are not apparent when only the exterior of the eye is regarded, it can always be demonstrated. If one eye is examined with this instrument while the other is regarding a small area straight ahead, the eye being examined, which follows the movements of the other, is seen to move in various directions ”

“ After needling the lens in young people I have seen a rise of intra-ocular tension to 50 and 60 mm., maintained for many days, with considerable general deep hyperemia, and soreness of the globe, followed by gradual return to normal tension, and no permanent impairment of vision or the visual field.
One other type may be mentioned. That of an elderly patient with marked vascular disease, often renal involvement, and distinctly impaired nutrition. There may be renal retinitis or retinal hemorrhages. The case may easily become one of hemorrhagic glaucoma. It may run a very chronic course. ”

“ In adults it often seems to be produced by the action of strong reflected light, as by exposure to intense fires in forges, glasshouses, &c., or by a dependent 280position of the head, accompanied with exposure to light. People advanced in life are most subject to the disease.29 It is not an unfrequent consequence of internal ophthalmia, and almost invariably follows the slightest wound or most delicate puncture of the lens: it often occurs after slight injury of the lens or its capsule, inflicted during attempts to form an artificial pupil. ”

“ The ophthalmoscope has become an instrument of incalculable value to the oculist. Many changes in the retina and interior of the eye, which are due to disease, can be observed and examined by means of the ophthalmoscope ”

“ No matter what their degree or their duration their cure is accomplished just as soon as the patient is able to secure mental control. The cause of any error of refraction, of a squint, or of any other functional disturbance of the eye, is simply a thought - a wrong thought - and the cure is as quick as the thought that relaxes. In a fraction of a second the highest degrees of refractive error may be corrected, a squint may disappear, or the blindness of amblyopia may be relieved. ”

“ The retina is not so easily excited into action by less irritation after having been lately subjected to greater. 1. When any one passes from the bright daylight into a darkened room, the irises of his eyes expand themselves to their utmost extent in a few seconds of time; but it is very long before the optic nerve, after having been stimulated by the greater light of the day, becomes sensible of the less degree of it in the room; and, if the room is not too obscure, the irises will again contract themselves in some degree, as the sensibility of the retina returns. ”

“ Extraordinary precautions are taken in our homes, offices and schools to temper the light, whether natural or artificial, and to insure that it shall not shine directly into the eyes; smoked and amber glasses, eye-shades, broad-brimmed hats and parasols are commonly used to protect the organs of vision from what is considered an excess of light; and when actual disease is present, it is no uncommon thing for patients to be kept for weeks, months and years in dark rooms, or with bandages over their eyes.
It is not light but darkness that is dangerous to the eye. ”

“ Vision, as determined by the official test types, must not fall below 20/40 in either eye, and not below 20/20 unless the defect is a simple refractive error not hyperopia, is not due to ocular disease, and is entirely corrected by proper glasses. ”

“ With the left eye he could just distinguish light in the outer upper field of vision. With the ophthalmoscope only the lower fundus of the left eye could be made out, where the retinal vessels were seen up to the lower edge of the optic disk. The disk itself could not be made out, but above it a bulging, detached retina was prominent, with a hemorrhagic spot at its inner margin. In the upper outer fundus another separate bulging detachment of the retina could be plainly seen. ”

“ Experiment and calculation have gone far to settle the precise mode in which light gives rise to sight, and affects our perception and judgment of external objects, and the condition of the eye during life and health or disease has been brought into view by the ophthalmoscope. The names of Helmholtz and of Donders are inseparably connected with modern advances in the physiology of the eye, while no English name is more conspicuous in regard to the surgery of the eye than that with which we commence this chapter. ”

“ I shall make a point of calling daily, but shall not examine your eyes every time. The excitement and the effort would strain the optic nerve. Our object is to keep the inflammation from striking inwards. I should not tell you all this, but I see that you have much self-command. On that and your constitution, under Providence, the cure depends. One question. I am not a professed ophthalmist, would you prefer to have one? ”

“ Hydrophthalmia, also, is a disease in which little hope can be entertained of materially benefiting the patient. In the slighter cases, in which no very annoying symptoms accompany the affection, vision may be improved by the use of optical instruments; mercurial preparations may be employed in moderation, with the view of promoting absorption of the superabundant fluid. When the disease has made considerable progress, temporary relief may be obtained from puncturing the cornea at its lower part, so as to discharge the accumulated aqueous humour ”

“ 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. ”

“ Of Cataract, or opacity of the crystalline lens and its capsule, attended with partial loss of vision.—The disease is, in general,278 gradual in its progress: but sometimes it advances rapidly, as when occasioned by a blow or wound. When slow, the opacity commences in the centre of the lens, and extends gradually towards the circumference. Before any change can be perceived in the organ, the patient sees objects as if covered with a mist or veil; and, as the opacity becomes distinct, vision is gradually impaired. ”

“ In the retina the displacement, derangement, or covering up of the cones and rods necessarily interferes with or abolishes sight, the opacity of the cornea, lens, capsule, or vitreous interrupts the rays of light, and the destruction, or coating over of the pigment of the choroid leads to undue reflection and destroys vision. ”

“ Excessive illumination alters the proper perception of the coloring of the mucosa, besides shortening the life of the lamps. The proper degree of brightness is obtained when, as the current is increased, the first change from yellow to white light is obtained. Never turn up the rheostat without watching the lamp. ”

“ The optic nerve being seated at the bottom of the eye, has the images of surrounding objects painted upon it; it looks out through the different humors. The different membranes and humours which compose the eye, and serve for vision, are, the tunica conjunctiva, the tunica sclerotica, the cornea, the iris, the pupil, the choroides, and the retina. ”

“ About twenty-five years ago a patient came to the New York Eye Infirmary with well-marked atrophy of the optic nerve. According to all that we know of the laws of pathology he should have been totally blind; yet his vision was normal. ”

“ SUN-GAZING Light is necessary to the health of the eye, and darkness is injurious to it. Eye shades, dark glasses, darkened rooms, weaken the sight and sooner or later produce inflammations. Persons with normal sight can look directly at the sun, or at the strongest artificial light, without injury or discomfort, and persons with imperfect sight are never permanently injured by such lights, though temporary ill effects, lasting from a few minutes to a few hours, days, weeks, months, or longer, may be produced. In all abnormal conditions of the eyes, light is beneficial. ”

“ The ophthalmoscope has laid bare to our view a living nerve of special sense, the highly-developed end-organ in which it terminates, and the blood-columns circulating in them. In no other part of the body has Nature vouchsafed to us so clear an insight into her mysteries. ”

“ The lens becomes opaque and greenish as the disease advances, vision gradually diminishes, and the iris is immovable. After sight is lost, the patient has a perception of a luminous appearance in the organ when pressed upon. Both eyes are generally affected, one after the other; headache, often violent, attends the disease; many remedies, both external and internal, may be tried on recommendation, though without effect: the disease seldom, if ever, admits of cure. ”

“ The apparatus of rods, cones, and other structures are absolutely essential to enable light to give that stimulus to the optic nerve which, conveyed to the brain, is converted into visual sensations. So if this apparatus were absent in our organs of vision, in vain would the optic nerve proper be spread out over the interior of the eyeball: we should be no more able to see with such eyes than we are able to see with our hands.
We now invite the reader’s careful consideration to the diagram, Fig. 236, which is a section of the retina through the yellow spot. ”

“ In this case, while the retina, or optic nerve, was deprived of light, its excitability accumulated, or became more easily affected by light; for if a person goes out of one room, into another which has an equal degree of light, he will feel no effect. You may convince yourselves of this law by a very simple experiment—shut your eyes, and cover them for a minute or two with your hand, and endeavour not to think of the light, or of what you are doing ”

“ Numerous other instruments of precision are now in constant use, among the most wonderful of which perhaps is the ophthalmoscope, whereby we are enabled to subject the retina and the intervening media of the eye to minute visual examination. There is not an organ of the body that is not now interrogated daily in the way of physical diagnosis, and we even examine separately the secretion of each of the two kidneys. ”

“ The first type brings us near to what may be the essential nature of glaucoma, impairment of ocular nutrition by the intra-ocular tension, which is generally elevated, but may not be above the usual normal. A special weakness in the nutrition of nerve tissue may be assumed. It would help to explain the cavernous atrophy of the optic nerve associated with simple glaucoma. ”